binlog.cc

/* Copyright (c) 2009, 2013 Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software Foundation,
   51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA */


#include "my_global.h"
#include "log.h"
#include "binlog.h"
#include "log_event.h"
#include "rpl_filter.h"
#include "rpl_rli.h"
#include "sql_plugin.h"
#include "rpl_handler.h"
#include "rpl_info_factory.h"
#include "rpl_utility.h"
#include "debug_sync.h"
#include "global_threads.h"
#include "sql_show.h"
#include "sql_parse.h"
#include "rpl_mi.h"
#include <list>
#include <string>
#include <my_stacktrace.h>

using std::max;
using std::min;
using std::string;
using std::list;

#define FLAGSTR(V,F) ((V)&(F)?#F" ":"")

#define MY_OFF_T_UNDEF (~(my_off_t)0UL)

/*
  Constants required for the limit unsafe warnings suppression
 */
//seconds after which the limit unsafe warnings suppression will be activated
#define LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT 50
//number of limit unsafe warnings after which the suppression will be activated
#define LIMIT_UNSAFE_WARNING_ACTIVATION_THRESHOLD_COUNT 50
#define MAX_SESSION_ATTACH_TRIES 10

static ulonglong limit_unsafe_suppression_start_time= 0;
static bool unsafe_warning_suppression_is_activated= false;
static int limit_unsafe_warning_count= 0;

static handlerton *binlog_hton;
bool opt_binlog_order_commits= true;

const char *log_bin_index= 0;
const char *log_bin_basename= 0;

MYSQL_BIN_LOG mysql_bin_log(&sync_binlog_period);

static int binlog_init(void *p);
static int binlog_start_trans_and_stmt(THD *thd, Log_event *start_event);
static int binlog_close_connection(handlerton *hton, THD *thd);
static int binlog_savepoint_set(handlerton *hton, THD *thd, void *sv);
static int binlog_savepoint_rollback(handlerton *hton, THD *thd, void *sv);
static int binlog_commit(handlerton *hton, THD *thd, bool all);
static int binlog_rollback(handlerton *hton, THD *thd, bool all);
static int binlog_prepare(handlerton *hton, THD *thd, bool all);


class Mutex_sentry
{
public:
  Mutex_sentry(mysql_mutex_t *mutex)
    : m_mutex(mutex)
  {
    if (m_mutex)
      mysql_mutex_lock(mutex);
  }

  ~Mutex_sentry()
  {
    if (m_mutex)
      mysql_mutex_unlock(m_mutex);
#ifndef DBUG_OFF
    m_mutex= 0;
#endif
  }

private:
  mysql_mutex_t *m_mutex;

  // It's not allowed to copy this object in any way
  Mutex_sentry(Mutex_sentry const&);
  void operator=(Mutex_sentry const&);
};


static void print_system_time()
{
#ifdef __WIN__
  SYSTEMTIME utc_time;
  GetSystemTime(&utc_time);
  const long hrs=  utc_time.wHour;
  const long mins= utc_time.wMinute;
  const long secs= utc_time.wSecond;
#else
  /* Using time() instead of my_time() to avoid looping */
  const time_t curr_time= time(NULL);
  /* Calculate time of day */
  const long tmins = curr_time / 60;
  const long thrs  = tmins / 60;
  const long hrs   = thrs  % 24;
  const long mins  = tmins % 60;
  const long secs  = curr_time % 60;
#endif
  char hrs_buf[3]= "00";
  char mins_buf[3]= "00";
  char secs_buf[3]= "00";
  int base= 10;
  my_safe_itoa(base, hrs, &hrs_buf[2]);
  my_safe_itoa(base, mins, &mins_buf[2]);
  my_safe_itoa(base, secs, &secs_buf[2]);

  my_safe_printf_stderr("---------- %s:%s:%s UTC - ",
                        hrs_buf, mins_buf, secs_buf);
}


class Thread_excursion
{
public:
  Thread_excursion(THD *thd)
    : m_original_thd(thd)
#ifdef WITH_PERFSCHEMA_STORAGE_ENGINE
    , m_saved_psi(PSI_server ? PSI_server->get_thread() : NULL)
#endif
  {
  }

  ~Thread_excursion() {
#ifdef WITH_PERFSCHEMA_STORAGE_ENGINE
    if (PSI_server)
      PSI_server->set_thread(m_saved_psi);
#endif
#ifndef EMBEDDED_LIBRARY
    if (unlikely(setup_thread_globals(m_original_thd)))
      DBUG_ASSERT(0);                           // Out of memory?!
#endif
  }

  void try_to_attach_to(THD *thd)
  {
    int i= 0;
    /*
      Attach the POSIX thread to a session in MAX_SESSION_ATTACH_TRIES
      tries when encountering 'out of memory' error.
    */
    while (i < MAX_SESSION_ATTACH_TRIES)
    {
      /*
        Currently attach_to(...) returns ER_OUTOFMEMORY or 0. So
        we continue to attach the POSIX thread when encountering
        the ER_OUTOFMEMORY error. Please take care other error
        returned from attach_to(...) in future.
      */
      if (!attach_to(thd))
      {
        if (i > 0)
          sql_print_warning("Server overcomes the temporary 'out of memory' "
                            "in '%d' tries while attaching to session thread "
                            "during the group commit phase.\n", i + 1);
        break;
      }
      i++;
    }
    /*
      Terminate the server after failed to attach the POSIX thread
      to a session in MAX_SESSION_ATTACH_TRIES tries.
    */
    if (MAX_SESSION_ATTACH_TRIES == i)
    {
      print_system_time();
      my_safe_printf_stderr("%s", "[Fatal] Out of memory while attaching to "
                            "session thread during the group commit phase. "
                            "Data consistency between master and slave can "
                            "be guaranteed after server restarts.\n");
      _exit(EXIT_FAILURE);
    }
  }

private:

  int attach_to(THD *thd)
  {
#ifdef WITH_PERFSCHEMA_STORAGE_ENGINE
    if (PSI_server)
      PSI_server->set_thread(thd_get_psi(thd));
#endif
#ifndef EMBEDDED_LIBRARY
    if (DBUG_EVALUATE_IF("simulate_session_attach_error", 1, 0)
        || unlikely(setup_thread_globals(thd)))
    {
#ifdef WITH_PERFSCHEMA_STORAGE_ENGINE
      if (PSI_server)
        PSI_server->set_thread(m_saved_psi);
#endif /* WITH_PERFSCHEMA_STORAGE_ENGINE */
      /*
        Indirectly uses pthread_setspecific, which can only return
        ENOMEM or EINVAL. Since store_globals are using correct keys,
        the only alternative is out of memory.
      */
      return ER_OUTOFMEMORY;
    }
#endif /* EMBEDDED_LIBRARY */
    return 0;
  }

  int setup_thread_globals(THD *thd) const {
    int error= 0;
    THD *original_thd= my_pthread_getspecific(THD*, THR_THD);
    MEM_ROOT* original_mem_root= my_pthread_getspecific(MEM_ROOT*, THR_MALLOC);
    if ((error= my_pthread_setspecific_ptr(THR_THD, thd)))
      goto exit0;
    if ((error= my_pthread_setspecific_ptr(THR_MALLOC, &thd->mem_root)))
      goto exit1;
    if ((error= set_mysys_var(thd->mysys_var)))
      goto exit2;
    goto exit0;
exit2:
    error= my_pthread_setspecific_ptr(THR_MALLOC,  original_mem_root);
exit1:
    error= my_pthread_setspecific_ptr(THR_THD,  original_thd);
exit0:
    return error;
  }

  THD *m_original_thd;
  PSI_thread *m_saved_psi;
};


class binlog_cache_data
{
public:

  binlog_cache_data(bool trx_cache_arg,
                    my_off_t max_binlog_cache_size_arg,
                    ulong *ptr_binlog_cache_use_arg,
                    ulong *ptr_binlog_cache_disk_use_arg)
  : m_pending(0), saved_max_binlog_cache_size(max_binlog_cache_size_arg),
    ptr_binlog_cache_use(ptr_binlog_cache_use_arg),
    ptr_binlog_cache_disk_use(ptr_binlog_cache_disk_use_arg)
  {
    reset();
    flags.transactional= trx_cache_arg;
    cache_log.end_of_file= saved_max_binlog_cache_size;
  }

  int finalize(THD *thd, Log_event *end_event);
  int flush(THD *thd, my_off_t *bytes, bool *wrote_xid);
  int write_event(THD *thd, Log_event *event);

  virtual ~binlog_cache_data()
  {
    DBUG_ASSERT(is_binlog_empty());
    close_cached_file(&cache_log);
  }

  bool is_binlog_empty() const
  {
    my_off_t pos= my_b_tell(&cache_log);
    DBUG_PRINT("debug", ("%s_cache - pending: 0x%llx, bytes: %llu",
                         (flags.transactional ? "trx" : "stmt"),
                         (ulonglong) pending(), (ulonglong) pos));
    return pending() == NULL && pos == 0;
  }

  bool is_group_cache_empty() const
  {
    return group_cache.is_empty();
  }

#ifndef DBUG_OFF
  bool dbug_is_finalized() const {
    return flags.finalized;
  }
#endif

  Rows_log_event *pending() const
  {
    return m_pending;
  }

  void set_pending(Rows_log_event *const pending)
  {
    m_pending= pending;
  }

  void set_incident(void)
  {
    flags.incident= true;
  }

  bool has_incident(void) const
  {
    return flags.incident;
  }

  bool has_xid() const {
    // There should only be an XID event if we are transactional
    DBUG_ASSERT((flags.transactional && flags.with_xid) || !flags.with_xid);
    return flags.with_xid;
  }

  bool is_trx_cache() const
  {
    return flags.transactional;
  }

  my_off_t get_byte_position() const
  {
    return my_b_tell(&cache_log);
  }

  virtual void reset()
  {
    compute_statistics();
    truncate(0);
    flags.incident= false;
    flags.with_xid= false;
    flags.immediate= false;
    flags.finalized= false;
    /*
      The truncate function calls reinit_io_cache that calls my_b_flush_io_cache
      which may increase disk_writes. This breaks the disk_writes use by the
      binary log which aims to compute the ratio between in-memory cache usage
      and disk cache usage. To avoid this undesirable behavior, we reset the
      variable after truncating the cache.
    */
    cache_log.disk_writes= 0;
    group_cache.clear();
    DBUG_ASSERT(is_binlog_empty());
  }

  /*
    Sets the write position to point at the position given. If the
    cache has swapped to a file, it reinitializes it, so that the
    proper data is added to the IO_CACHE buffer. Otherwise, it just
    does a my_b_seek.

    my_b_seek will not work if the cache has swapped, that's why
    we do this workaround.

    @param[IN]  pos the new write position.
    @param[IN]  use_reinit if the position should be reset resorting
                to reset_io_cache (which may issue a flush_io_cache 
                inside)

    @return The previous write position.
   */
  my_off_t reset_write_pos(my_off_t pos, bool use_reinit)
  {
    DBUG_ENTER("reset_write_pos");
    DBUG_ASSERT(cache_log.type == WRITE_CACHE);

    my_off_t oldpos= get_byte_position();

    if (use_reinit)
      reinit_io_cache(&cache_log, WRITE_CACHE, pos, 0, 0);
    else
      my_b_seek(&cache_log, pos);

    DBUG_RETURN(oldpos);
  }

  /*
    Cache to store data before copying it to the binary log.
  */
  IO_CACHE cache_log;

  Group_cache group_cache;

protected:
  /*
    It truncates the cache to a certain position. This includes deleting the
    pending event.
   */
  void truncate(my_off_t pos)
  {
    DBUG_PRINT("info", ("truncating to position %lu", (ulong) pos));
    remove_pending_event();
    reinit_io_cache(&cache_log, WRITE_CACHE, pos, 0, 0);
    cache_log.end_of_file= saved_max_binlog_cache_size;
  }

  int flush_pending_event(THD *thd) {
    if (m_pending)
    {
      m_pending->set_flags(Rows_log_event::STMT_END_F);
      if (int error= write_event(thd, m_pending))
        return error;
      thd->clear_binlog_table_maps();
    }
    return 0;
  }

  int remove_pending_event() {
    delete m_pending;
    m_pending= NULL;
    return 0;
  }
  struct Flags {
    /*
      Defines if this is either a trx-cache or stmt-cache, respectively, a
      transactional or non-transactional cache.
    */
    bool transactional:1;

    /*
      This indicates that some events did not get into the cache and most likely
      it is corrupted.
    */
    bool incident:1;

    /*
      This indicates that the cache should be written without BEGIN/END.
    */
    bool immediate:1;

    /*
      This flag indicates that the buffer was finalized and has to be
      flushed to disk.
     */
    bool finalized:1;

    /*
      This indicates that the cache contain an XID event.
     */
    bool with_xid:1;
  } flags;

private:
  /*
    Pending binrows event. This event is the event where the rows are currently
    written.
   */
  Rows_log_event *m_pending;

  void compute_statistics()
  {
    if (!is_binlog_empty())
    {
      statistic_increment(*ptr_binlog_cache_use, &LOCK_status);
      if (cache_log.disk_writes != 0)
        statistic_increment(*ptr_binlog_cache_disk_use, &LOCK_status);
    }
  }

  /*
    Stores the values of maximum size of the cache allowed when this cache
    is configured. This corresponds to either
      . max_binlog_cache_size or max_binlog_stmt_cache_size.
  */
  my_off_t saved_max_binlog_cache_size;

  /*
    Stores a pointer to the status variable that keeps track of the in-memory 
    cache usage. This corresponds to either
      . binlog_cache_use or binlog_stmt_cache_use.
  */
  ulong *ptr_binlog_cache_use;

  /*
    Stores a pointer to the status variable that keeps track of the disk
    cache usage. This corresponds to either
      . binlog_cache_disk_use or binlog_stmt_cache_disk_use.
  */
  ulong *ptr_binlog_cache_disk_use;

  binlog_cache_data& operator=(const binlog_cache_data& info);
  binlog_cache_data(const binlog_cache_data& info);
};


class binlog_stmt_cache_data
  : public binlog_cache_data
{
public:
  binlog_stmt_cache_data(bool trx_cache_arg,
                        my_off_t max_binlog_cache_size_arg,
                        ulong *ptr_binlog_cache_use_arg,
                        ulong *ptr_binlog_cache_disk_use_arg)
    : binlog_cache_data(trx_cache_arg,
                        max_binlog_cache_size_arg,
                        ptr_binlog_cache_use_arg,
                        ptr_binlog_cache_disk_use_arg)
  {
  }

  using binlog_cache_data::finalize;

  int finalize(THD *thd);
};


int
binlog_stmt_cache_data::finalize(THD *thd)
{
  if (flags.immediate)
  {
    if (int error= finalize(thd, NULL))
      return error;
  }
  else
  {
    Query_log_event
      end_evt(thd, STRING_WITH_LEN("COMMIT"), false, false, true, 0, true);
    if (int error= finalize(thd, &end_evt))
      return error;
  }
  return 0;
}


class binlog_trx_cache_data : public binlog_cache_data
{
public:
  binlog_trx_cache_data(bool trx_cache_arg,
                        my_off_t max_binlog_cache_size_arg,
                        ulong *ptr_binlog_cache_use_arg,
                        ulong *ptr_binlog_cache_disk_use_arg)
  : binlog_cache_data(trx_cache_arg,
                      max_binlog_cache_size_arg,
                      ptr_binlog_cache_use_arg,
                      ptr_binlog_cache_disk_use_arg),
    m_cannot_rollback(FALSE), before_stmt_pos(MY_OFF_T_UNDEF)
  {   }

  void reset()
  {
    DBUG_ENTER("reset");
    DBUG_PRINT("enter", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    m_cannot_rollback= FALSE;
    before_stmt_pos= MY_OFF_T_UNDEF;
    binlog_cache_data::reset();
    DBUG_PRINT("return", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    DBUG_VOID_RETURN;
  }

  bool cannot_rollback() const
  {
    return m_cannot_rollback;
  }

  void set_cannot_rollback()
  {
    m_cannot_rollback= TRUE;
  }

  my_off_t get_prev_position() const
  {
     return before_stmt_pos;
  }

  void set_prev_position(my_off_t pos)
  {
    DBUG_ENTER("set_prev_position");
    DBUG_PRINT("enter", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    before_stmt_pos= pos;
    DBUG_PRINT("return", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    DBUG_VOID_RETURN;
  }

  void restore_prev_position()
  {
    DBUG_ENTER("restore_prev_position");
    DBUG_PRINT("enter", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    binlog_cache_data::truncate(before_stmt_pos);
    before_stmt_pos= MY_OFF_T_UNDEF;
    DBUG_PRINT("return", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    DBUG_VOID_RETURN;
  }

  void restore_savepoint(my_off_t pos)
  {
    DBUG_ENTER("restore_savepoint");
    DBUG_PRINT("enter", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    binlog_cache_data::truncate(pos);
    if (pos <= before_stmt_pos)
      before_stmt_pos= MY_OFF_T_UNDEF;
    DBUG_PRINT("return", ("before_stmt_pos: %llu", (ulonglong) before_stmt_pos));
    DBUG_VOID_RETURN;
  }

  using binlog_cache_data::truncate;

  int truncate(THD *thd, bool all);

private:
  /*
    It will be set TRUE if any statement which cannot be rolled back safely
    is put in trx_cache.
  */
  bool m_cannot_rollback;

  /*
    Binlog position before the start of the current statement.
  */
  my_off_t before_stmt_pos;

  binlog_trx_cache_data& operator=(const binlog_trx_cache_data& info);
  binlog_trx_cache_data(const binlog_trx_cache_data& info);
};

class binlog_cache_mngr {
public:
  binlog_cache_mngr(my_off_t max_binlog_stmt_cache_size_arg,
                    ulong *ptr_binlog_stmt_cache_use_arg,
                    ulong *ptr_binlog_stmt_cache_disk_use_arg,
                    my_off_t max_binlog_cache_size_arg,
                    ulong *ptr_binlog_cache_use_arg,
                    ulong *ptr_binlog_cache_disk_use_arg)
  : stmt_cache(FALSE, max_binlog_stmt_cache_size_arg,
               ptr_binlog_stmt_cache_use_arg,
               ptr_binlog_stmt_cache_disk_use_arg),
    trx_cache(TRUE, max_binlog_cache_size_arg,
              ptr_binlog_cache_use_arg,
              ptr_binlog_cache_disk_use_arg)
  {  }

  binlog_cache_data* get_binlog_cache_data(bool is_transactional)
  {
    if (is_transactional)
      return &trx_cache;
    else
      return &stmt_cache;
  }

  IO_CACHE* get_binlog_cache_log(bool is_transactional)
  {
    return (is_transactional ? &trx_cache.cache_log : &stmt_cache.cache_log);
  }

  bool is_binlog_empty() const {
    return stmt_cache.is_binlog_empty() && trx_cache.is_binlog_empty();
  }

#ifndef DBUG_OFF
  bool dbug_any_finalized() const {
    return stmt_cache.dbug_is_finalized() || trx_cache.dbug_is_finalized();
  }
#endif

  /*
    Convenience method to flush both caches to the binary log.

    @param bytes_written Pointer to variable that will be set to the
                         number of bytes written for the flush.
    @param wrote_xid     Pointer to variable that will be set to @c
                         true if any XID event was written to the
                         binary log. Otherwise, the variable will not
                         be touched.
    @return Error code on error, zero if no error.
   */
  int flush(THD *thd, my_off_t *bytes_written, bool *wrote_xid)
  {
    my_off_t stmt_bytes= 0;
    my_off_t trx_bytes= 0;
    DBUG_ASSERT(stmt_cache.has_xid() == 0 && trx_cache.has_xid() <= 1);
    if (int error= stmt_cache.flush(thd, &stmt_bytes, wrote_xid))
      return error;
    if (int error= trx_cache.flush(thd, &trx_bytes, wrote_xid))
      return error;
    *bytes_written= stmt_bytes + trx_bytes;
    return 0;
  }

  binlog_stmt_cache_data stmt_cache;
  binlog_trx_cache_data trx_cache;

private:

  binlog_cache_mngr& operator=(const binlog_cache_mngr& info);
  binlog_cache_mngr(const binlog_cache_mngr& info);
};


static binlog_cache_mngr *thd_get_cache_mngr(const THD *thd)
{
  /* 
    If opt_bin_log is not set, binlog_hton->slot == -1 and hence
    thd_get_ha_data(thd, hton) segfaults.
  */
  DBUG_ASSERT(opt_bin_log);
  return (binlog_cache_mngr *)thd_get_ha_data(thd, binlog_hton);
}


void check_binlog_cache_size(THD *thd)
{
  if (binlog_cache_size > max_binlog_cache_size)
  {
    if (thd)
    {
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_BINLOG_CACHE_SIZE_GREATER_THAN_MAX,
                          ER(ER_BINLOG_CACHE_SIZE_GREATER_THAN_MAX),
                          (ulong) binlog_cache_size,
                          (ulong) max_binlog_cache_size);
    }
    else
    {
      sql_print_warning(ER_DEFAULT(ER_BINLOG_CACHE_SIZE_GREATER_THAN_MAX),
                        (ulong) binlog_cache_size,
                        (ulong) max_binlog_cache_size);
    }
    binlog_cache_size= max_binlog_cache_size;
  }
}

void check_binlog_stmt_cache_size(THD *thd)
{
  if (binlog_stmt_cache_size > max_binlog_stmt_cache_size)
  {
    if (thd)
    {
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_BINLOG_STMT_CACHE_SIZE_GREATER_THAN_MAX,
                          ER(ER_BINLOG_STMT_CACHE_SIZE_GREATER_THAN_MAX),
                          (ulong) binlog_stmt_cache_size,
                          (ulong) max_binlog_stmt_cache_size);
    }
    else
    {
      sql_print_warning(ER_DEFAULT(ER_BINLOG_STMT_CACHE_SIZE_GREATER_THAN_MAX),
                        (ulong) binlog_stmt_cache_size,
                        (ulong) max_binlog_stmt_cache_size);
    }
    binlog_stmt_cache_size= max_binlog_stmt_cache_size;
  }
}

bool binlog_enabled()
{
        return(binlog_hton && binlog_hton->slot != HA_SLOT_UNDEF);
}

 /*
  Save position of binary log transaction cache.

  SYNPOSIS
    binlog_trans_log_savepos()

    thd      The thread to take the binlog data from
    pos      Pointer to variable where the position will be stored

  DESCRIPTION

    Save the current position in the binary log transaction cache into
    the variable pointed to by 'pos'
 */

static void
binlog_trans_log_savepos(THD *thd, my_off_t *pos)
{
  DBUG_ENTER("binlog_trans_log_savepos");
  DBUG_ASSERT(pos != NULL);
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);
  DBUG_ASSERT(mysql_bin_log.is_open());
  *pos= cache_mngr->trx_cache.get_byte_position();
  DBUG_PRINT("return", ("position: %lu", (ulong) *pos));
  DBUG_VOID_RETURN;
}


/*
  this function is mostly a placeholder.
  conceptually, binlog initialization (now mostly done in MYSQL_BIN_LOG::open)
  should be moved here.
*/

static int binlog_init(void *p)
{
  binlog_hton= (handlerton *)p;
  binlog_hton->state=opt_bin_log ? SHOW_OPTION_YES : SHOW_OPTION_NO;
  binlog_hton->db_type=DB_TYPE_BINLOG;
  binlog_hton->savepoint_offset= sizeof(my_off_t);
  binlog_hton->close_connection= binlog_close_connection;
  binlog_hton->savepoint_set= binlog_savepoint_set;
  binlog_hton->savepoint_rollback= binlog_savepoint_rollback;
  binlog_hton->commit= binlog_commit;
  binlog_hton->rollback= binlog_rollback;
  binlog_hton->prepare= binlog_prepare;
  binlog_hton->flags= HTON_NOT_USER_SELECTABLE | HTON_HIDDEN;
  return 0;
}

static int binlog_close_connection(handlerton *hton, THD *thd)
{
  DBUG_ENTER("binlog_close_connection");
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);
  DBUG_ASSERT(cache_mngr->is_binlog_empty());
  DBUG_ASSERT(cache_mngr->trx_cache.is_group_cache_empty() &&
              cache_mngr->stmt_cache.is_group_cache_empty());
  DBUG_PRINT("debug", ("Set ha_data slot %d to 0x%llx", binlog_hton->slot, (ulonglong) NULL));
  thd_set_ha_data(thd, binlog_hton, NULL);
  cache_mngr->~binlog_cache_mngr();
  my_free(cache_mngr);
  DBUG_RETURN(0);
}

int binlog_cache_data::write_event(THD *thd, Log_event *ev)
{
  DBUG_ENTER("binlog_cache_data::write_event");

  if (gtid_mode > 0)
  {
    Group_cache::enum_add_group_status status= 
      group_cache.add_logged_group(thd, get_byte_position());
    if (status == Group_cache::ERROR)
      DBUG_RETURN(1);
    else if (status == Group_cache::APPEND_NEW_GROUP)
    {
      Gtid_log_event gtid_ev(thd, is_trx_cache());
      if (gtid_ev.write(&cache_log) != 0)
        DBUG_RETURN(1);
    }
  }

  if (ev != NULL)
  {
    DBUG_EXECUTE_IF("simulate_disk_full_at_flush_pending",
                  {DBUG_SET("+d,simulate_file_write_error");});
    if (ev->write(&cache_log) != 0)
    {
      DBUG_EXECUTE_IF("simulate_disk_full_at_flush_pending",
                      {
                        DBUG_SET("-d,simulate_file_write_error");
                        DBUG_SET("-d,simulate_disk_full_at_flush_pending");
                        /* 
                           after +d,simulate_file_write_error the local cache
                           is in unsane state. Since -d,simulate_file_write_error
                           revokes the first simulation do_write_cache()
                           can't be run without facing an assert.
                           So it's blocked with the following 2nd simulation:
                        */
                        DBUG_SET("+d,simulate_do_write_cache_failure");
                      });
      DBUG_RETURN(1);
    }
    if (ev->get_type_code() == XID_EVENT)
      flags.with_xid= true;
    if (ev->is_using_immediate_logging())
      flags.immediate= true;
  }
  DBUG_RETURN(0);
}


static int write_one_empty_group_to_cache(THD *thd,
                                          binlog_cache_data *cache_data,
                                          Gtid gtid)
{
  DBUG_ENTER("write_one_empty_group_to_cache");
  Group_cache *group_cache= &cache_data->group_cache;
  if (group_cache->contains_gtid(gtid))
    DBUG_RETURN(0);
  /*
    Apparently this code is not being called. We need to
    investigate if this is a bug or this code is not
    necessary. /Alfranio

    Empty groups are currently being handled in the function
    gtid_empty_group_log_and_cleanup().
  */
  DBUG_ASSERT(0); /*NOTREACHED*/
#ifdef NON_ERROR_GTID
  IO_CACHE *cache= &cache_data->cache_log;
  Group_cache::enum_add_group_status status= group_cache->add_empty_group(gtid);
  if (status == Group_cache::ERROR)
    DBUG_RETURN(1);
  DBUG_ASSERT(status == Group_cache::APPEND_NEW_GROUP);
  Gtid_specification spec= { GTID_GROUP, gtid };
  Gtid_log_event gtid_ev(thd, cache_data->is_trx_cache(), &spec);
  if (gtid_ev.write(cache) != 0)
    DBUG_RETURN(1);
#endif
  DBUG_RETURN(0);
}

static int write_empty_groups_to_cache(THD *thd, binlog_cache_data *cache_data)
{
  DBUG_ENTER("write_empty_groups_to_cache");
  if (thd->owned_gtid.sidno == -1)
  {
#ifdef HAVE_GTID_NEXT_LIST
    Gtid_set::Gtid_iterator git(&thd->owned_gtid_set);
    Gtid gtid= git.get();
    while (gtid.sidno != 0)
    {
      if (write_one_empty_group_to_cache(thd, cache_data, gtid) != 0)
        DBUG_RETURN(1);
      git.next();
      gtid= git.get();
    }
#else
    DBUG_ASSERT(0);
#endif
  }
  else if (thd->owned_gtid.sidno > 0)
    if (write_one_empty_group_to_cache(thd, cache_data, thd->owned_gtid) != 0)
      DBUG_RETURN(1);
  DBUG_RETURN(0);
}


static int
gtid_before_write_cache(THD* thd, binlog_cache_data* cache_data)
{
  DBUG_ENTER("gtid_before_write_cache");
  int error= 0;

  DBUG_ASSERT(thd->variables.gtid_next.type != UNDEFINED_GROUP);

  if (gtid_mode == 0)
    DBUG_RETURN(0);

  Group_cache* group_cache= &cache_data->group_cache;

  global_sid_lock->rdlock();

  if (thd->variables.gtid_next.type == AUTOMATIC_GROUP)
  {
    if (group_cache->generate_automatic_gno(thd) !=
        RETURN_STATUS_OK)
    {
      global_sid_lock->unlock();
      DBUG_RETURN(1); 
    }
  }
  if (write_empty_groups_to_cache(thd, cache_data) != 0)
  {
    global_sid_lock->unlock();
    DBUG_RETURN(1);
  }

  global_sid_lock->unlock();

  /*
    If an automatic group number was generated, change the first event
    into a "real" one.
  */
  if (thd->variables.gtid_next.type == AUTOMATIC_GROUP)
  {
    DBUG_ASSERT(group_cache->get_n_groups() == 1);
    Cached_group *cached_group= group_cache->get_unsafe_pointer(0);
    DBUG_ASSERT(cached_group->spec.type != AUTOMATIC_GROUP);
    Gtid_log_event gtid_ev(thd, cache_data->is_trx_cache(),
                           &cached_group->spec);
    bool using_file= cache_data->cache_log.pos_in_file > 0;
    my_off_t saved_position= cache_data->reset_write_pos(0, using_file);
    error= gtid_ev.write(&cache_data->cache_log);
    cache_data->reset_write_pos(saved_position, using_file);
  }

  DBUG_RETURN(error);
}

int gtid_empty_group_log_and_cleanup(THD *thd)
{
  int ret= 1;
  binlog_cache_data* cache_data= NULL;
  
  DBUG_ENTER("gtid_empty_group_log_and_cleanup");

  Query_log_event qinfo(thd, STRING_WITH_LEN("BEGIN"), TRUE,
                          FALSE, TRUE, 0, TRUE);
  DBUG_ASSERT(!qinfo.is_using_immediate_logging());

  /*
    thd->cache_mngr is uninitialized on the first empty transaction.
  */
  if (thd->binlog_setup_trx_data())
    DBUG_RETURN(1);
  cache_data= &thd_get_cache_mngr(thd)->trx_cache;
  DBUG_PRINT("debug", ("Writing to trx_cache"));
  if (cache_data->write_event(thd, &qinfo) ||
      gtid_before_write_cache(thd, cache_data))
    goto err;

  ret= mysql_bin_log.commit(thd, true);

err:
  DBUG_RETURN(ret);
}

int
binlog_cache_data::finalize(THD *thd, Log_event *end_event)
{
  DBUG_ENTER("binlog_cache_data::finalize");
  if (!is_binlog_empty())
  {
    DBUG_ASSERT(!flags.finalized);
    if (int error= flush_pending_event(thd))
      DBUG_RETURN(error);
    if (int error= write_event(thd, end_event))
      DBUG_RETURN(error);
    flags.finalized= true;
    DBUG_PRINT("debug", ("flags.finalized: %s", YESNO(flags.finalized)));
  }
  DBUG_RETURN(0);
}

int
binlog_cache_data::flush(THD *thd, my_off_t *bytes_written, bool *wrote_xid)
{
  /*
    Doing a commit or a rollback including non-transactional tables,
    i.e., ending a transaction where we might write the transaction
    cache to the binary log.

    We can always end the statement when ending a transaction since
    transactions are not allowed inside stored functions. If they
    were, we would have to ensure that we're not ending a statement
    inside a stored function.
  */
  DBUG_ENTER("binlog_cache_data::flush");
  DBUG_PRINT("debug", ("flags.finalized: %s", YESNO(flags.finalized)));
  int error= 0;
  if (flags.finalized)
  {
    my_off_t bytes_in_cache= my_b_tell(&cache_log);
    DBUG_PRINT("debug", ("bytes_in_cache: %llu", bytes_in_cache));
    /*
      The cache is always reset since subsequent rollbacks of the
      transactions might trigger attempts to write to the binary log
      if the cache is not reset.
     */
    if (!(error= gtid_before_write_cache(thd, this)))
      error= mysql_bin_log.write_cache(thd, this);

    if (flags.with_xid && error == 0)
      *wrote_xid= true;

    /*
      Reset have to be after the if above, since it clears the
      with_xid flag
    */
    reset();
    if (bytes_written)
      *bytes_written= bytes_in_cache;
  }
  DBUG_ASSERT(!flags.finalized);
  DBUG_RETURN(error);
}

int
binlog_trx_cache_data::truncate(THD *thd, bool all)
{
  DBUG_ENTER("binlog_trx_cache_data::truncate");
  int error=0;

  DBUG_PRINT("info", ("thd->options={ %s %s}, transaction: %s",
                      FLAGSTR(thd->variables.option_bits, OPTION_NOT_AUTOCOMMIT),
                      FLAGSTR(thd->variables.option_bits, OPTION_BEGIN),
                      all ? "all" : "stmt"));

  remove_pending_event();

  /*
    If rolling back an entire transaction or a single statement not
    inside a transaction, we reset the transaction cache.
  */
  if (ending_trans(thd, all))
  {
    if (has_incident())
      error= mysql_bin_log.write_incident(thd, true/*need_lock_log=true*/);
    reset();
  }
  /*
    If rolling back a statement in a transaction, we truncate the
    transaction cache to remove the statement.
  */
  else if (get_prev_position() != MY_OFF_T_UNDEF)
  {
    restore_prev_position();
    if (is_binlog_empty())
    {
      /*
        After restoring the previous position, we need to check if
        the cache is empty. In such case, the group cache needs to
        be cleaned up too because the GTID is removed too from the
        cache.

        So if any change happens again, the GTID must be rewritten
        and this will not happen if the group cache is not cleaned
        up.

        After integrating this with NDB, we need to check if the
        current approach is enough or the group cache needs to
        explicitly support rollback to savepoints.
      */
      group_cache.clear();
    }
  }

  thd->clear_binlog_table_maps();

  DBUG_RETURN(error);
}

static int binlog_prepare(handlerton *hton, THD *thd, bool all)
{
  /*
    do nothing.
    just pretend we can do 2pc, so that MySQL won't
    switch to 1pc.
    real work will be done in MYSQL_BIN_LOG::commit()
  */
  return 0;
}

static int binlog_commit(handlerton *hton, THD *thd, bool all)
{
  DBUG_ENTER("binlog_commit");
  /*
    Nothing to do (any more) on commit.
   */
  DBUG_RETURN(0);
}

static int binlog_rollback(handlerton *hton, THD *thd, bool all)
{
  DBUG_ENTER("binlog_rollback");
  int error= 0;
  if (thd->lex->sql_command == SQLCOM_ROLLBACK_TO_SAVEPOINT)
    error= mysql_bin_log.rollback(thd, all);
  DBUG_RETURN(error);
}


bool
Stage_manager::Mutex_queue::append(THD *first)
{
  DBUG_ENTER("Stage_manager::Mutex_queue::append");
  lock();
  DBUG_PRINT("enter", ("first: 0x%llx", (ulonglong) first));
  DBUG_PRINT("info", ("m_first: 0x%llx, &m_first: 0x%llx, m_last: 0x%llx",
                       (ulonglong) m_first, (ulonglong) &m_first,
                       (ulonglong) m_last));
  bool empty= (m_first == NULL);
  *m_last= first;
  DBUG_PRINT("info", ("m_first: 0x%llx, &m_first: 0x%llx, m_last: 0x%llx",
                       (ulonglong) m_first, (ulonglong) &m_first,
                       (ulonglong) m_last));
  /*
    Go to the last THD instance of the list. We expect lists to be
    moderately short. If they are not, we need to track the end of
    the queue as well.
  */
  while (first->next_to_commit)
    first= first->next_to_commit;
  m_last= &first->next_to_commit;
  DBUG_PRINT("info", ("m_first: 0x%llx, &m_first: 0x%llx, m_last: 0x%llx",
                        (ulonglong) m_first, (ulonglong) &m_first,
                        (ulonglong) m_last));
  DBUG_ASSERT(m_first || m_last == &m_first);
  DBUG_PRINT("return", ("empty: %s", YESNO(empty)));
  unlock();
  DBUG_RETURN(empty);
}


std::pair<bool, THD*>
Stage_manager::Mutex_queue::pop_front()
{
  DBUG_ENTER("Stage_manager::Mutex_queue::pop_front");
  lock();
  THD *result= m_first;
  bool more= true;
  /*
    We do not set next_to_commit to NULL here since this is only used
    in the flush stage. We will have to call fetch_queue last here,
    and will then "cut" the linked list by setting the end of that
    queue to NULL.
  */
  if (result)
    m_first= result->next_to_commit;
  if (m_first == NULL)
  {
    more= false;
    m_last = &m_first;
  }
  DBUG_ASSERT(m_first || m_last == &m_first);
  unlock();
  DBUG_PRINT("return", ("result: 0x%llx, more: %s",
                        (ulonglong) result, YESNO(more)));
  DBUG_RETURN(std::make_pair(more, result));
}


bool
Stage_manager::enroll_for(StageID stage, THD *thd, mysql_mutex_t *stage_mutex)
{
  // If the queue was empty: we're the leader for this batch
  DBUG_PRINT("debug", ("Enqueue 0x%llx to queue for stage %d",
                       (ulonglong) thd, stage));
  bool leader= m_queue[stage].append(thd);

  /*
    The stage mutex can be NULL if we are enrolling for the first
    stage.
  */
  if (stage_mutex)
    mysql_mutex_unlock(stage_mutex);

  /*
    If the queue was not empty, we're a follower and wait for the
    leader to process the queue. If we were holding a mutex, we have
    to release it before going to sleep.
  */
  if (!leader)
  {
    mysql_mutex_lock(&m_lock_done);
#ifndef DBUG_OFF
    /*
      Leader can be awaiting all-clear to preempt follower's execution.
      With setting the status the follower ensures it won't execute anything
      including thread-specific code.
    */
    thd->transaction.flags.ready_preempt= 1;
    if (leader_await_preempt_status)
      mysql_cond_signal(&m_cond_preempt);
#endif
    while (thd->transaction.flags.pending)
      mysql_cond_wait(&m_cond_done, &m_lock_done);
    mysql_mutex_unlock(&m_lock_done);
  }
  return leader;
}


THD *Stage_manager::Mutex_queue::fetch_and_empty()
{
  DBUG_ENTER("Stage_manager::Mutex_queue::fetch_and_empty");
  lock();
  DBUG_PRINT("enter", ("m_first: 0x%llx, &m_first: 0x%llx, m_last: 0x%llx",
                       (ulonglong) m_first, (ulonglong) &m_first,
                       (ulonglong) m_last));
  THD *result= m_first;
  m_first= NULL;
  m_last= &m_first;
  DBUG_PRINT("info", ("m_first: 0x%llx, &m_first: 0x%llx, m_last: 0x%llx",
                       (ulonglong) m_first, (ulonglong) &m_first,
                       (ulonglong) m_last));
  DBUG_ASSERT(m_first || m_last == &m_first);
  DBUG_PRINT("return", ("result: 0x%llx", (ulonglong) result));
  unlock();
  DBUG_RETURN(result);
}

#ifndef DBUG_OFF
void Stage_manager::clear_preempt_status(THD *head)
{
  DBUG_ASSERT(head);

  mysql_mutex_lock(&m_lock_done);
  while(!head->transaction.flags.ready_preempt)
  {
    leader_await_preempt_status= true;
    mysql_cond_wait(&m_cond_preempt, &m_lock_done);
  }
  leader_await_preempt_status= false;
  mysql_mutex_unlock(&m_lock_done);
}
#endif

int MYSQL_BIN_LOG::rollback(THD *thd, bool all)
{
  int error= 0;
  bool stuff_logged= false;

  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);
  DBUG_ENTER("MYSQL_BIN_LOG::rollback(THD *thd, bool all)");
  DBUG_PRINT("enter", ("all: %s, cache_mngr: 0x%llx, thd->is_error: %s",
                       YESNO(all), (ulonglong) cache_mngr, YESNO(thd->is_error())));

  /*
    We roll back the transaction in the engines early since this will
    release locks and allow other transactions to start executing.

    If we are executing a ROLLBACK TO SAVEPOINT, we should only clear
    the caches since this function is called as part of the engine
    rollback.
   */
  if (thd->lex->sql_command != SQLCOM_ROLLBACK_TO_SAVEPOINT)
    if ((error= ha_rollback_low(thd, all)))
      goto end;

  /*
    If there is no cache manager, or if there is nothing in the
    caches, there are no caches to roll back, so we're trivially done.
   */
  if (cache_mngr == NULL || cache_mngr->is_binlog_empty())
    goto end;

  DBUG_PRINT("debug",
             ("all.cannot_safely_rollback(): %s, trx_cache_empty: %s",
              YESNO(thd->transaction.all.cannot_safely_rollback()),
              YESNO(cache_mngr->trx_cache.is_binlog_empty())));
  DBUG_PRINT("debug",
             ("stmt.cannot_safely_rollback(): %s, stmt_cache_empty: %s",
              YESNO(thd->transaction.stmt.cannot_safely_rollback()),
              YESNO(cache_mngr->stmt_cache.is_binlog_empty())));

  /*
    If an incident event is set we do not flush the content of the statement
    cache because it may be corrupted.
  */
  if (cache_mngr->stmt_cache.has_incident())
  {
    error= write_incident(thd, true/*need_lock_log=true*/);
    cache_mngr->stmt_cache.reset();
  }
  else if (!cache_mngr->stmt_cache.is_binlog_empty())
  {
    if ((error= cache_mngr->stmt_cache.finalize(thd)))
      goto end;
    stuff_logged= true;
  }

  if (ending_trans(thd, all))
  {
    if (trans_cannot_safely_rollback(thd))
    {
      /*
        If the transaction is being rolled back and contains changes that
        cannot be rolled back, the trx-cache's content is flushed.
      */
      Query_log_event
        end_evt(thd, STRING_WITH_LEN("ROLLBACK"), true, false, true, 0, true);
      error= cache_mngr->trx_cache.finalize(thd, &end_evt);
      stuff_logged= true;
    }
    else
    {
      /*
        If the transaction is being rolled back and its changes can be
        rolled back, the trx-cache's content is truncated.
      */
      error= cache_mngr->trx_cache.truncate(thd, all);
    }
  }
  else
  {
    /*
      If a statement is being rolled back, it is necessary to know
      exactly why a statement may not be safely rolled back as in
      some specific situations the trx-cache can be truncated.

      If a temporary table is created or dropped, the trx-cache is not
      truncated. Note that if the stmt-cache is used, there is nothing
      to truncate in the trx-cache.

      If a non-transactional table is updated and the binlog format is
      statement, the trx-cache is not truncated. The trx-cache is used
      when the direct option is off and a transactional table has been
      updated before the current statement in the context of the
      current transaction. Note that if the stmt-cache is used there is
      nothing to truncate in the trx-cache.

      If other binlog formats are used, updates to non-transactional
      tables are written to the stmt-cache and trx-cache can be safely
      truncated, if necessary.
    */
    if (thd->transaction.stmt.has_dropped_temp_table() ||
        thd->transaction.stmt.has_created_temp_table() ||
        (thd->transaction.stmt.has_modified_non_trans_table() &&
        thd->variables.binlog_format == BINLOG_FORMAT_STMT))
    {
      /*
        If the statement is being rolled back and dropped or created a
        temporary table or modified a non-transactional table and the
        statement-based replication is in use, the statement's changes
        in the trx-cache are preserved.
      */
      cache_mngr->trx_cache.set_prev_position(MY_OFF_T_UNDEF);
    }
    else
    {
      /*
        Otherwise, the statement's changes in the trx-cache are
        truncated.
      */
      error= cache_mngr->trx_cache.truncate(thd, all);
    }
  }

  DBUG_PRINT("debug", ("error: %d", error));
  if (error == 0 && stuff_logged)
    error= ordered_commit(thd, all, /* skip_commit */ true);

  if (check_write_error(thd))
  {
    /*
      "all == true" means that a "rollback statement" triggered the error and
      this function was called. However, this must not happen as a rollback
      is written directly to the binary log. And in auto-commit mode, a single
      statement that is rolled back has the flag all == false.
    */
    DBUG_ASSERT(!all);
    /*
      We reach this point if the effect of a statement did not properly get into
      a cache and need to be rolled back.
    */
    error |= cache_mngr->trx_cache.truncate(thd, all);
  }

end:
  /*
    When a statement errors out on auto-commit mode it is rollback
    implicitly, so the same should happen to its GTID.
  */
  if (!thd->in_active_multi_stmt_transaction())
    gtid_rollback(thd);

  DBUG_PRINT("return", ("error: %d", error));
  DBUG_RETURN(error);
}

static int binlog_savepoint_set(handlerton *hton, THD *thd, void *sv)
{
  DBUG_ENTER("binlog_savepoint_set");
  int error= 1;

  String log_query;
  if (log_query.append(STRING_WITH_LEN("SAVEPOINT ")))
    DBUG_RETURN(error);
  else
    append_identifier(thd, &log_query, thd->lex->ident.str,
                      thd->lex->ident.length);

  int errcode= query_error_code(thd, thd->killed == THD::NOT_KILLED);
  Query_log_event qinfo(thd, log_query.c_ptr_safe(), log_query.length(),
                        TRUE, FALSE, TRUE, errcode);
  /* 
    We cannot record the position before writing the statement
    because a rollback to a savepoint (.e.g. consider it "S") would
    prevent the savepoint statement (i.e. "SAVEPOINT S") from being
    written to the binary log despite the fact that the server could
    still issue other rollback statements to the same savepoint (i.e. 
    "S"). 
    Given that the savepoint is valid until the server releases it,
    ie, until the transaction commits or it is released explicitly,
    we need to log it anyway so that we don't have "ROLLBACK TO S"
    or "RELEASE S" without the preceding "SAVEPOINT S" in the binary
    log.
  */
  if (!(error= mysql_bin_log.write_event(&qinfo)))
    binlog_trans_log_savepos(thd, (my_off_t*) sv);

  DBUG_RETURN(error);
}

static int binlog_savepoint_rollback(handlerton *hton, THD *thd, void *sv)
{
  DBUG_ENTER("binlog_savepoint_rollback");
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);
  my_off_t pos= *(my_off_t*) sv;
  DBUG_ASSERT(pos != ~(my_off_t) 0);

  /*
    Write ROLLBACK TO SAVEPOINT to the binlog cache if we have updated some
    non-transactional table. Otherwise, truncate the binlog cache starting
    from the SAVEPOINT command.
  */
  if (trans_cannot_safely_rollback(thd))
  {
    String log_query;
    if (log_query.append(STRING_WITH_LEN("ROLLBACK TO ")) ||
        log_query.append("`") ||
        log_query.append(thd->lex->ident.str, thd->lex->ident.length) ||
        log_query.append("`"))
      DBUG_RETURN(1);
    int errcode= query_error_code(thd, thd->killed == THD::NOT_KILLED);
    Query_log_event qinfo(thd, log_query.c_ptr_safe(), log_query.length(),
                          TRUE, FALSE, TRUE, errcode);
    DBUG_RETURN(mysql_bin_log.write_event(&qinfo));
  }
  // Otherwise, we truncate the cache
  cache_mngr->trx_cache.restore_savepoint(pos);
  if (cache_mngr->trx_cache.is_binlog_empty())
    cache_mngr->trx_cache.group_cache.clear();
  DBUG_RETURN(0);
}

#ifdef HAVE_REPLICATION

/*
  Adjust the position pointer in the binary log file for all running slaves

  SYNOPSIS
    adjust_linfo_offsets()
    purge_offset        Number of bytes removed from start of log index file

  NOTES
    - This is called when doing a PURGE when we delete lines from the
      index log file

  REQUIREMENTS
    - Before calling this function, we have to ensure that no threads are
      using any binary log file before purge_offset.a

  TODO
    - Inform the slave threads that they should sync the position
      in the binary log file with flush_relay_log_info.
      Now they sync is done for next read.
*/

static void adjust_linfo_offsets(my_off_t purge_offset)
{
  mysql_mutex_lock(&LOCK_thread_count);

  Thread_iterator it= global_thread_list_begin();
  Thread_iterator end= global_thread_list_end();
  for (; it != end; ++it)
  {
    LOG_INFO* linfo;
    if ((linfo = (*it)->current_linfo))
    {
      mysql_mutex_lock(&linfo->lock);
      /*
        Index file offset can be less that purge offset only if
        we just started reading the index file. In that case
        we have nothing to adjust
      */
      if (linfo->index_file_offset < purge_offset)
        linfo->fatal = (linfo->index_file_offset != 0);
      else
        linfo->index_file_offset -= purge_offset;
      mysql_mutex_unlock(&linfo->lock);
    }
  }
  mysql_mutex_unlock(&LOCK_thread_count);
}


static int log_in_use(const char* log_name)
{
  size_t log_name_len = strlen(log_name) + 1;
  int thread_count=0;

  mysql_mutex_lock(&LOCK_thread_count);

  Thread_iterator it= global_thread_list_begin();
  Thread_iterator end= global_thread_list_end();
  for (; it != end; ++it)
  {
    LOG_INFO* linfo;
    if ((linfo = (*it)->current_linfo))
    {
      mysql_mutex_lock(&linfo->lock);
      if(!memcmp(log_name, linfo->log_file_name, log_name_len))
      {
        thread_count++;
        sql_print_warning("file %s was not purged because it was being read"
                          "by thread number %llu", log_name,
                          (ulonglong)(*it)->thread_id);
      }
      mysql_mutex_unlock(&linfo->lock);
    }
  }

  mysql_mutex_unlock(&LOCK_thread_count);
  return thread_count;
}

static bool purge_error_message(THD* thd, int res)
{
  uint errcode;

  if ((errcode= purge_log_get_error_code(res)) != 0)
  {
    my_message(errcode, ER(errcode), MYF(0));
    return TRUE;
  }
  my_ok(thd);
  return FALSE;
}

#endif /* HAVE_REPLICATION */

int check_binlog_magic(IO_CACHE* log, const char** errmsg)
{
  char magic[4];
  DBUG_ASSERT(my_b_tell(log) == 0);

  if (my_b_read(log, (uchar*) magic, sizeof(magic)))
  {
    *errmsg = "I/O error reading the header from the binary log";
    sql_print_error("%s, errno=%d, io cache code=%d", *errmsg, my_errno,
                    log->error);
    return 1;
  }
  if (memcmp(magic, BINLOG_MAGIC, sizeof(magic)))
  {
    *errmsg = "Binlog has bad magic number;  It's not a binary log file that can be used by this version of MySQL";
    return 1;
  }
  return 0;
}


File open_binlog_file(IO_CACHE *log, const char *log_file_name, const char **errmsg)
{
  File file;
  DBUG_ENTER("open_binlog_file");

  if ((file= mysql_file_open(key_file_binlog,
                             log_file_name, O_RDONLY | O_BINARY | O_SHARE,
                             MYF(MY_WME))) < 0)
  {
    sql_print_error("Failed to open log (file '%s', errno %d)",
                    log_file_name, my_errno);
    *errmsg = "Could not open log file";
    goto err;
  }
  if (init_io_cache(log, file, IO_SIZE*2, READ_CACHE, 0, 0,
                    MYF(MY_WME|MY_DONT_CHECK_FILESIZE)))
  {
    sql_print_error("Failed to create a cache on log (file '%s')",
                    log_file_name);
    *errmsg = "Could not open log file";
    goto err;
  }
  if (check_binlog_magic(log,errmsg))
    goto err;
  DBUG_RETURN(file);

err:
  if (file >= 0)
  {
    mysql_file_close(file, MYF(0));
    end_io_cache(log);
  }
  DBUG_RETURN(-1);
}

bool
trans_has_updated_trans_table(const THD* thd)
{
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);

  return (cache_mngr ? !cache_mngr->trx_cache.is_binlog_empty() : 0);
}

bool
stmt_has_updated_trans_table(const THD *thd)
{
  Ha_trx_info *ha_info;

  for (ha_info= thd->transaction.stmt.ha_list; ha_info;
       ha_info= ha_info->next())
  {
    if (ha_info->is_trx_read_write() && ha_info->ht() != binlog_hton)
      return (TRUE);
  }
  return (FALSE);
}

bool ending_trans(THD* thd, const bool all)
{
  return (all || ending_single_stmt_trans(thd, all));
}

bool ending_single_stmt_trans(THD* thd, const bool all)
{
  return (!all && !thd->in_multi_stmt_transaction_mode());
}

bool trans_cannot_safely_rollback(const THD* thd)
{
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);

  return cache_mngr->trx_cache.cannot_rollback();
}

bool stmt_cannot_safely_rollback(const THD* thd)
{
  return thd->transaction.stmt.cannot_safely_rollback();
}

#ifndef EMBEDDED_LIBRARY

bool purge_master_logs(THD* thd, const char* to_log)
{
  char search_file_name[FN_REFLEN];
  if (!mysql_bin_log.is_open())
  {
    my_ok(thd);
    return FALSE;
  }

  mysql_bin_log.make_log_name(search_file_name, to_log);
  return purge_error_message(thd,
                             mysql_bin_log.purge_logs(search_file_name, false,
                                                      true/*need_lock_index=true*/,
                                                      true/*need_update_threads=true*/,
                                                      NULL, false));
}


bool purge_master_logs_before_date(THD* thd, time_t purge_time)
{
  if (!mysql_bin_log.is_open())
  {
    my_ok(thd);
    return 0;
  }
  return purge_error_message(thd,
                             mysql_bin_log.purge_logs_before_date(purge_time,
                                                                  false));
}
#endif /* EMBEDDED_LIBRARY */

/*
  Helper function to get the error code of the query to be binlogged.
 */
int query_error_code(THD *thd, bool not_killed)
{
  int error;
  
  if (not_killed || (thd->killed == THD::KILL_BAD_DATA))
  {
    error= thd->is_error() ? thd->get_stmt_da()->sql_errno() : 0;

    /* thd->get_stmt_da()->sql_errno() might be ER_SERVER_SHUTDOWN or
       ER_QUERY_INTERRUPTED, So here we need to make sure that error
       is not set to these errors when specified not_killed by the
       caller.
    */
    if (error == ER_SERVER_SHUTDOWN || error == ER_QUERY_INTERRUPTED)
      error= 0;
  }
  else
  {
    /* killed status for DELAYED INSERT thread should never be used */
    DBUG_ASSERT(!(thd->system_thread & SYSTEM_THREAD_DELAYED_INSERT));
    error= thd->killed_errno();
  }

  return error;
}


static bool copy_file(IO_CACHE *from, IO_CACHE *to, my_off_t offset)
{
  int bytes_read;
  uchar io_buf[IO_SIZE*2];
  DBUG_ENTER("copy_file");

  mysql_file_seek(from->file, offset, MY_SEEK_SET, MYF(0));
  while(TRUE)
  {
    if ((bytes_read= (int) mysql_file_read(from->file, io_buf, sizeof(io_buf),
                                           MYF(MY_WME)))
        < 0)
      goto err;
    if (DBUG_EVALUATE_IF("fault_injection_copy_part_file", 1, 0))
      bytes_read= bytes_read/2;
    if (!bytes_read)
      break;                                    // end of file
    if (mysql_file_write(to->file, io_buf, bytes_read, MYF(MY_WME | MY_NABP)))
      goto err;
  }

  DBUG_RETURN(0);

err:
  DBUG_RETURN(1);
}


#ifdef HAVE_REPLICATION

int log_loaded_block(IO_CACHE* file)
{
  DBUG_ENTER("log_loaded_block");
  LOAD_FILE_INFO *lf_info;
  uint block_len;
  /* buffer contains position where we started last read */
  uchar* buffer= (uchar*) my_b_get_buffer_start(file);
  uint max_event_size= current_thd->variables.max_allowed_packet;
  lf_info= (LOAD_FILE_INFO*) file->arg;
  if (lf_info->thd->is_current_stmt_binlog_format_row())
    DBUG_RETURN(0);
  if (lf_info->last_pos_in_file != HA_POS_ERROR &&
      lf_info->last_pos_in_file >= my_b_get_pos_in_file(file))
    DBUG_RETURN(0);
  
  for (block_len= (uint) (my_b_get_bytes_in_buffer(file)); block_len > 0;
       buffer += min(block_len, max_event_size),
       block_len -= min(block_len, max_event_size))
  {
    lf_info->last_pos_in_file= my_b_get_pos_in_file(file);
    if (lf_info->wrote_create_file)
    {
      Append_block_log_event a(lf_info->thd, lf_info->thd->db, buffer,
                               min(block_len, max_event_size),
                               lf_info->log_delayed);
      if (mysql_bin_log.write_event(&a))
        DBUG_RETURN(1);
    }
    else
    {
      Begin_load_query_log_event b(lf_info->thd, lf_info->thd->db,
                                   buffer,
                                   min(block_len, max_event_size),
                                   lf_info->log_delayed);
      if (mysql_bin_log.write_event(&b))
        DBUG_RETURN(1);
      lf_info->wrote_create_file= 1;
    }
  }
  DBUG_RETURN(0);
}

/* Helper function for SHOW BINLOG/RELAYLOG EVENTS */
bool show_binlog_events(THD *thd, MYSQL_BIN_LOG *binary_log)
{
  Protocol *protocol= thd->protocol;
  List<Item> field_list;
  const char *errmsg = 0;
  bool ret = TRUE;
  IO_CACHE log;
  File file = -1;
  int old_max_allowed_packet= thd->variables.max_allowed_packet;
  LOG_INFO linfo;

  DBUG_ENTER("show_binlog_events");

  DBUG_ASSERT(thd->lex->sql_command == SQLCOM_SHOW_BINLOG_EVENTS ||
              thd->lex->sql_command == SQLCOM_SHOW_RELAYLOG_EVENTS);

  Format_description_log_event *description_event= new
    Format_description_log_event(3); /* MySQL 4.0 by default */

  if (binary_log->is_open())
  {
    LEX_MASTER_INFO *lex_mi= &thd->lex->mi;
    SELECT_LEX_UNIT *unit= &thd->lex->unit;
    ha_rows event_count, limit_start, limit_end;
    my_off_t pos = max<my_off_t>(BIN_LOG_HEADER_SIZE, lex_mi->pos); // user-friendly
    char search_file_name[FN_REFLEN], *name;
    const char *log_file_name = lex_mi->log_file_name;
    mysql_mutex_t *log_lock = binary_log->get_log_lock();
    Log_event* ev;

    unit->set_limit(thd->lex->current_select);
    limit_start= unit->offset_limit_cnt;
    limit_end= unit->select_limit_cnt;

    name= search_file_name;
    if (log_file_name)
      binary_log->make_log_name(search_file_name, log_file_name);
    else
      name=0;                                   // Find first log

    linfo.index_file_offset = 0;

    if (binary_log->find_log_pos(&linfo, name, true/*need_lock_index=true*/))
    {
      errmsg = "Could not find target log";
      goto err;
    }

    mysql_mutex_lock(&LOCK_thread_count);
    thd->current_linfo = &linfo;
    mysql_mutex_unlock(&LOCK_thread_count);

    if ((file=open_binlog_file(&log, linfo.log_file_name, &errmsg)) < 0)
      goto err;

    /*
      to account binlog event header size
    */
    thd->variables.max_allowed_packet += MAX_LOG_EVENT_HEADER;

    DEBUG_SYNC(thd, "after_show_binlog_event_found_file");

    mysql_mutex_lock(log_lock);

    /*
      open_binlog_file() sought to position 4.
      Read the first event in case it's a Format_description_log_event, to
      know the format. If there's no such event, we are 3.23 or 4.x. This
      code, like before, can't read 3.23 binlogs.
      This code will fail on a mixed relay log (one which has Format_desc then
      Rotate then Format_desc).
    */
    ev= Log_event::read_log_event(&log, (mysql_mutex_t*)0, description_event,
                                   opt_master_verify_checksum);
    if (ev)
    {
      if (ev->get_type_code() == FORMAT_DESCRIPTION_EVENT)
      {
        delete description_event;
        description_event= (Format_description_log_event*) ev;
      }
      else
        delete ev;
    }

    my_b_seek(&log, pos);

    if (!description_event->is_valid())
    {
      errmsg="Invalid Format_description event; could be out of memory";
      goto err;
    }

    for (event_count = 0;
         (ev = Log_event::read_log_event(&log, (mysql_mutex_t*) 0,
                                         description_event,
                                         opt_master_verify_checksum)); )
    {
      if (ev->get_type_code() == FORMAT_DESCRIPTION_EVENT)
        description_event->checksum_alg= ev->checksum_alg;

      if (event_count >= limit_start &&
          ev->net_send(protocol, linfo.log_file_name, pos))
      {
        errmsg = "Net error";
        delete ev;
        mysql_mutex_unlock(log_lock);
        goto err;
      }

      pos = my_b_tell(&log);
      delete ev;

      if (++event_count >= limit_end)
        break;
    }

    if (event_count < limit_end && log.error)
    {
      errmsg = "Wrong offset or I/O error";
      mysql_mutex_unlock(log_lock);
      goto err;
    }

    mysql_mutex_unlock(log_lock);
  }
  // Check that linfo is still on the function scope.
  DEBUG_SYNC(thd, "after_show_binlog_events");

  ret= FALSE;

err:
  delete description_event;
  if (file >= 0)
  {
    end_io_cache(&log);
    mysql_file_close(file, MYF(MY_WME));
  }

  if (errmsg)
    my_error(ER_ERROR_WHEN_EXECUTING_COMMAND, MYF(0),
             "SHOW BINLOG EVENTS", errmsg);
  else
    my_eof(thd);

  mysql_mutex_lock(&LOCK_thread_count);
  thd->current_linfo = 0;
  mysql_mutex_unlock(&LOCK_thread_count);
  thd->variables.max_allowed_packet= old_max_allowed_packet;
  DBUG_RETURN(ret);
}

bool mysql_show_binlog_events(THD* thd)
{
  Protocol *protocol= thd->protocol;
  List<Item> field_list;
  DBUG_ENTER("mysql_show_binlog_events");

  DBUG_ASSERT(thd->lex->sql_command == SQLCOM_SHOW_BINLOG_EVENTS);

  Log_event::init_show_field_list(&field_list);
  if (protocol->send_result_set_metadata(&field_list,
                            Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))
    DBUG_RETURN(TRUE);

  /*
    Wait for handlers to insert any pending information
    into the binlog.  For e.g. ndb which updates the binlog asynchronously
    this is needed so that the uses sees all its own commands in the binlog
  */
  ha_binlog_wait(thd);
  
  DBUG_RETURN(show_binlog_events(thd, &mysql_bin_log));
}

#endif /* HAVE_REPLICATION */


MYSQL_BIN_LOG::MYSQL_BIN_LOG(uint *sync_period)
  :bytes_written(0), file_id(1), open_count(1),
   sync_period_ptr(sync_period), sync_counter(0),
   m_prep_xids(0),
   is_relay_log(0), signal_cnt(0),
   checksum_alg_reset(BINLOG_CHECKSUM_ALG_UNDEF),
   relay_log_checksum_alg(BINLOG_CHECKSUM_ALG_UNDEF),
   previous_gtid_set(0)
{
  /*
    We don't want to initialize locks here as such initialization depends on
    safe_mutex (when using safe_mutex) which depends on MY_INIT(), which is
    called only in main(). Doing initialization here would make it happen
    before main().
  */
  index_file_name[0] = 0;
  memset(&index_file, 0, sizeof(index_file));
  memset(&purge_index_file, 0, sizeof(purge_index_file));
  memset(&crash_safe_index_file, 0, sizeof(crash_safe_index_file));
}


/* this is called only once */

void MYSQL_BIN_LOG::cleanup()
{
  DBUG_ENTER("cleanup");
  if (inited)
  {
    inited= 0;
    close(LOG_CLOSE_INDEX|LOG_CLOSE_STOP_EVENT);
    mysql_mutex_destroy(&LOCK_log);
    mysql_mutex_destroy(&LOCK_index);
    mysql_mutex_destroy(&LOCK_commit);
    mysql_mutex_destroy(&LOCK_sync);
    mysql_mutex_destroy(&LOCK_xids);
    mysql_cond_destroy(&update_cond);
    my_atomic_rwlock_destroy(&m_prep_xids_lock);
    mysql_cond_destroy(&m_prep_xids_cond);
    stage_manager.deinit();
  }
  DBUG_VOID_RETURN;
}


void MYSQL_BIN_LOG::init_pthread_objects()
{
  MYSQL_LOG::init_pthread_objects();
  mysql_mutex_init(m_key_LOCK_index, &LOCK_index, MY_MUTEX_INIT_SLOW);
  mysql_mutex_init(m_key_LOCK_commit, &LOCK_commit, MY_MUTEX_INIT_FAST);
  mysql_mutex_init(m_key_LOCK_sync, &LOCK_sync, MY_MUTEX_INIT_FAST);
  mysql_mutex_init(m_key_LOCK_xids, &LOCK_xids, MY_MUTEX_INIT_FAST);
  mysql_cond_init(m_key_update_cond, &update_cond, 0);
  my_atomic_rwlock_init(&m_prep_xids_lock);
  mysql_cond_init(m_key_prep_xids_cond, &m_prep_xids_cond, NULL);
  stage_manager.init(
#ifdef HAVE_PSI_INTERFACE
                   m_key_LOCK_flush_queue,
                   m_key_LOCK_sync_queue,
                   m_key_LOCK_commit_queue,
                   m_key_LOCK_done, m_key_COND_done
#endif
                   );
}

bool MYSQL_BIN_LOG::open_index_file(const char *index_file_name_arg,
                                    const char *log_name, bool need_lock_index)
{
  File index_file_nr= -1;
  DBUG_ASSERT(!my_b_inited(&index_file));

  /*
    First open of this class instance
    Create an index file that will hold all file names uses for logging.
    Add new entries to the end of it.
  */
  myf opt= MY_UNPACK_FILENAME;
  if (!index_file_name_arg)
  {
    index_file_name_arg= log_name;    // Use same basename for index file
    opt= MY_UNPACK_FILENAME | MY_REPLACE_EXT;
  }
  fn_format(index_file_name, index_file_name_arg, mysql_data_home,
            ".index", opt);

  if (set_crash_safe_index_file_name(index_file_name_arg))
  {
    sql_print_error("MYSQL_BIN_LOG::set_crash_safe_index_file_name failed.");
    return TRUE;
  }

  /*
    We need move crash_safe_index_file to index_file if the index_file
    does not exist and crash_safe_index_file exists when mysqld server
    restarts.
  */
  if (my_access(index_file_name, F_OK) &&
      !my_access(crash_safe_index_file_name, F_OK) &&
      my_rename(crash_safe_index_file_name, index_file_name, MYF(MY_WME)))
  {
    sql_print_error("MYSQL_BIN_LOG::open_index_file failed to "
                    "move crash_safe_index_file to index file.");
    return TRUE;
  }

  if ((index_file_nr= mysql_file_open(m_key_file_log_index,
                                      index_file_name,
                                      O_RDWR | O_CREAT | O_BINARY,
                                      MYF(MY_WME))) < 0 ||
       mysql_file_sync(index_file_nr, MYF(MY_WME)) ||
       init_io_cache(&index_file, index_file_nr,
                     IO_SIZE, READ_CACHE,
                     mysql_file_seek(index_file_nr, 0L, MY_SEEK_END, MYF(0)),
                                     0, MYF(MY_WME | MY_WAIT_IF_FULL)) ||
      DBUG_EVALUATE_IF("fault_injection_openning_index", 1, 0))
  {
    /*
      TODO: all operations creating/deleting the index file or a log, should
      call my_sync_dir() or my_sync_dir_by_file() to be durable.
      TODO: file creation should be done with mysql_file_create()
      not mysql_file_open().
    */
    if (index_file_nr >= 0)
      mysql_file_close(index_file_nr, MYF(0));
    return TRUE;
  }

#ifdef HAVE_REPLICATION
  /*
    Sync the index by purging any binary log file that is not registered.
    In other words, either purge binary log files that were removed from
    the index but not purged from the file system due to a crash or purge
    any binary log file that was created but not register in the index
    due to a crash.
  */

  if (set_purge_index_file_name(index_file_name_arg) ||
      open_purge_index_file(FALSE) ||
      purge_index_entry(NULL, NULL, need_lock_index) ||
      close_purge_index_file() ||
      DBUG_EVALUATE_IF("fault_injection_recovering_index", 1, 0))
  {
    sql_print_error("MYSQL_BIN_LOG::open_index_file failed to sync the index "
                    "file.");
    return TRUE;
  }
#endif

  return FALSE;
}


enum enum_read_gtids_from_binlog_status
{ GOT_GTIDS, GOT_PREVIOUS_GTIDS, NO_GTIDS, ERROR, TRUNCATED };
static enum_read_gtids_from_binlog_status
read_gtids_from_binlog(const char *filename, Gtid_set *all_gtids,
                       Gtid_set *prev_gtids, bool verify_checksum)
{
  DBUG_ENTER("read_gtids_from_binlog");
  DBUG_PRINT("info", ("Opening file %s", filename));

  /*
    Create a Format_description_log_event that is used to read the
    first event of the log.
  */
  Format_description_log_event fd_ev(BINLOG_VERSION), *fd_ev_p= &fd_ev;
  if (!fd_ev.is_valid())
    DBUG_RETURN(ERROR);

  File file;
  IO_CACHE log;

  const char *errmsg= NULL;
  if ((file= open_binlog_file(&log, filename, &errmsg)) < 0)
  {
    sql_print_error("%s", errmsg);
    /*
      We need to revisit the recovery procedure for relay log
      files. Currently, it is called after this routine.
      /Alfranio
    */
    DBUG_RETURN(TRUNCATED);
  }

  /*
    Seek for Previous_gtids_log_event and Gtid_log_event events to
    gather information what has been processed so far.
  */
  my_b_seek(&log, BIN_LOG_HEADER_SIZE);
  Log_event *ev= NULL;
  enum_read_gtids_from_binlog_status ret= NO_GTIDS;
  bool done= false;
  while (!done &&
         (ev= Log_event::read_log_event(&log, 0, fd_ev_p, verify_checksum)) !=
         NULL)
  {
    DBUG_PRINT("info", ("Read event of type %s", ev->get_type_str()));
    switch (ev->get_type_code())
    {
    case FORMAT_DESCRIPTION_EVENT:
      if (fd_ev_p != &fd_ev)
        delete fd_ev_p;
      fd_ev_p= (Format_description_log_event *)ev;
      break;
    case ROTATE_EVENT:
      // do nothing; just accept this event and go to next
      break;
    case PREVIOUS_GTIDS_LOG_EVENT:
    {
      if (gtid_mode == 0)
      {
        my_error(ER_FOUND_GTID_EVENT_WHEN_GTID_MODE_IS_OFF, MYF(0));
        ret= ERROR;
      }
      ret= GOT_PREVIOUS_GTIDS;
      // add events to sets
      Previous_gtids_log_event *prev_gtids_ev=
        (Previous_gtids_log_event *)ev;
      if (all_gtids != NULL && prev_gtids_ev->add_to_set(all_gtids) != 0)
        ret= ERROR, done= true;
      else if (prev_gtids != NULL && prev_gtids_ev->add_to_set(prev_gtids) != 0)
        ret= ERROR, done= true;
#ifndef DBUG_OFF
      char* prev_buffer= prev_gtids_ev->get_str(NULL, NULL);
      DBUG_PRINT("info", ("Got Previous_gtids from file '%s': Gtid_set='%s'.",
                          filename, prev_buffer));
      my_free(prev_buffer);
#endif
      break;
    }
    case GTID_LOG_EVENT:
    {
      DBUG_EXECUTE_IF("inject_fault_bug16502579", {
                      DBUG_PRINT("debug", ("GTID_LOG_EVENT found. Injected ret=NO_GTIDS."));
                      ret=NO_GTIDS;
                      });
      if (ret != GOT_GTIDS)
      {
        if (ret != GOT_PREVIOUS_GTIDS)
        {
          /*
            Since this routine is run on startup, there may not be a
            THD instance. Therefore, ER(X) cannot be used.
           */
          const char* msg_fmt= (current_thd != NULL) ?
                               ER(ER_BINLOG_LOGICAL_CORRUPTION) :
                               ER_DEFAULT(ER_BINLOG_LOGICAL_CORRUPTION);
          my_printf_error(ER_BINLOG_LOGICAL_CORRUPTION,
                          msg_fmt, MYF(0),
                          filename,
                          "The first global transaction identifier was read, but "
                          "no other information regarding identifiers existing "
                          "on the previous log files was found.");
          ret= ERROR, done= true;
          break;
        }
        else
          ret= GOT_GTIDS;
      }
      /*
        When all_gtids==NULL, we just check if the binary log contains
        at least one Gtid_log_event, so that we can distinguish the
        return values GOT_GTID and GOT_PREVIOUS_GTIDS. We don't need
        to read anything else from the binary log.
      */
      if (all_gtids == NULL)
        ret= GOT_GTIDS, done= true;
      else
      {
        Gtid_log_event *gtid_ev= (Gtid_log_event *)ev;
        rpl_sidno sidno= gtid_ev->get_sidno(false/*false=don't need lock*/);
        if (sidno < 0)
          ret= ERROR, done= true;
        {
          if (all_gtids->ensure_sidno(sidno) != RETURN_STATUS_OK)
            ret= ERROR, done= true;
          else if (all_gtids->_add_gtid(sidno, gtid_ev->get_gno()) !=
                   RETURN_STATUS_OK)
            ret= ERROR, done= true;
        }
        DBUG_PRINT("info", ("Got Gtid from file '%s': Gtid(%d, %lld).",
                            filename, sidno, gtid_ev->get_gno()));
      }
      break;
    }
    case ANONYMOUS_GTID_LOG_EVENT:
    default:
      // if we found any other event type without finding a
      // previous_gtids_log_event, then the rest of this binlog
      // cannot contain gtids
      if (ret != GOT_GTIDS && ret != GOT_PREVIOUS_GTIDS)
        done= true;
      break;
    }
    if (ev != fd_ev_p)
      delete ev;
    DBUG_PRINT("info", ("done=%d", done));
  }

  if (log.error < 0)
  {
    // This is not a fatal error; the log may just be truncated.

    // @todo but what other errors could happen? IO error?
    sql_print_warning("Error reading GTIDs from binary log: %d", log.error);
  }

  if (fd_ev_p != &fd_ev)
  {
    delete fd_ev_p;
    fd_ev_p= &fd_ev;
  }

  mysql_file_close(file, MYF(MY_WME));
  end_io_cache(&log);

  DBUG_PRINT("info", ("returning %d", ret));
  DBUG_RETURN(ret);
}

bool MYSQL_BIN_LOG::find_first_log_not_in_gtid_set(char *binlog_file_name,
                                                   const Gtid_set *gtid_set,
                                                   const char **errmsg)
{
  DBUG_ENTER("MYSQL_BIN_LOG::gtid_read_start_binlog");
  /*
    Gather the set of files to be accessed.
  */
  list<string> filename_list;
  LOG_INFO linfo;
  int error;

  list<string>::reverse_iterator rit;
  Gtid_set previous_gtid_set(gtid_set->get_sid_map());

  mysql_mutex_lock(&LOCK_index);
  for (error= find_log_pos(&linfo, NULL, false/*need_lock_index=false*/);
       !error; error= find_next_log(&linfo, false/*need_lock_index=false*/))
  {
    DBUG_PRINT("info", ("read log filename '%s'", linfo.log_file_name));
    filename_list.push_back(string(linfo.log_file_name));
  }
  mysql_mutex_unlock(&LOCK_index);
  if (error != LOG_INFO_EOF)
  {
    *errmsg= "Failed to read the binary log index file while "
      "looking for the oldest binary log that contains any GTID "
      "that is not in the given gtid set";
    error= -1;
    goto end;
  }

  if (filename_list.empty())
  {
    *errmsg= "Could not find first log file name in binary log index file "
      "while looking for the oldest binary log that contains any GTID "
      "that is not in the given gtid set";
    error= -2;
    goto end;
  }

  /*
    Iterate over all the binary logs in reverse order, and read only
    the Previous_gtids_log_event, to find the first one, that is the
    subset of the given gtid set. Since every binary log begins with
    a Previous_gtids_log_event, that contains all GTIDs in all
    previous binary logs.
  */
  DBUG_PRINT("info", ("Iterating backwards through binary logs, and reading "
                      "only the Previous_gtids_log_event, to find the first "
                      "one, that is the subset of the given gtid set."));
  rit= filename_list.rbegin();
  error= 0;
  while (rit != filename_list.rend())
  {
    const char *filename= rit->c_str();
    DBUG_PRINT("info", ("Read Previous_gtids_log_event from filename='%s'",
                        filename));
    switch (read_gtids_from_binlog(filename, NULL, &previous_gtid_set,
                                   opt_master_verify_checksum))
    {
    case ERROR:
      *errmsg= "Error reading header of binary log while looking for "
        "the oldest binary log that contains any GTID that is not in "
        "the given gtid set";
      error= -3;
      goto end;
    case NO_GTIDS:
      *errmsg= "Found old binary log without GTIDs while looking for "
        "the oldest binary log that contains any GTID that is not in "
        "the given gtid set";
      error= -4;
      goto end;
    case GOT_GTIDS:
    case GOT_PREVIOUS_GTIDS:
      if (previous_gtid_set.is_subset(gtid_set))
      {
        strcpy(binlog_file_name, filename);
        /*
          Verify that the selected binlog is not the first binlog,
        */
        DBUG_EXECUTE_IF("slave_reconnect_with_gtid_set_executed",
                        DBUG_ASSERT(strcmp(filename_list.begin()->c_str(),
                                           binlog_file_name) != 0););
        goto end;
      }
    case TRUNCATED:
      break;
    }
    previous_gtid_set.clear();

    rit++;
  }

  if (rit == filename_list.rend())
  {
    *errmsg= ER(ER_MASTER_HAS_PURGED_REQUIRED_GTIDS);
    error= -5;
  }

end:
  if (error)
    DBUG_PRINT("error", ("'%s'", *errmsg));
  filename_list.clear();
  DBUG_PRINT("info", ("returning %d", error));
  DBUG_RETURN(error != 0 ? true : false);
}

bool MYSQL_BIN_LOG::init_gtid_sets(Gtid_set *all_gtids, Gtid_set *lost_gtids,
                                   bool verify_checksum, bool need_lock)
{
  DBUG_ENTER("MYSQL_BIN_LOG::init_gtid_sets");
  DBUG_PRINT("info", ("lost_gtids=%p; so we are recovering a %s log",
                      lost_gtids, lost_gtids == NULL ? "relay" : "binary"));

  /*
    Acquires the necessary locks to ensure that logs are not either
    removed or updated when we are reading from it.
  */
  if (need_lock)
  {
    // We don't need LOCK_log if we are only going to read the initial
    // Prevoius_gtids_log_event and ignore the Gtid_log_events.
    if (all_gtids != NULL)
      mysql_mutex_lock(&LOCK_log);
    mysql_mutex_lock(&LOCK_index);
    global_sid_lock->wrlock();
  }
  else
  {
    if (all_gtids != NULL)
      mysql_mutex_assert_owner(&LOCK_log);
    mysql_mutex_assert_owner(&LOCK_index);
    global_sid_lock->assert_some_wrlock();
  }

  // Gather the set of files to be accessed.
  list<string> filename_list;
  LOG_INFO linfo;
  int error;

  list<string>::iterator it;
  list<string>::reverse_iterator rit;
  bool reached_first_file= false;

  for (error= find_log_pos(&linfo, NULL, false/*need_lock_index=false*/); !error;
       error= find_next_log(&linfo, false/*need_lock_index=false*/))
  {
    DBUG_PRINT("info", ("read log filename '%s'", linfo.log_file_name));
    filename_list.push_back(string(linfo.log_file_name));
  }
  if (error != LOG_INFO_EOF)
  {
    DBUG_PRINT("error", ("Error reading binlog index"));
    goto end;
  }
  error= 0;

  if (all_gtids != NULL)
  {
    DBUG_PRINT("info", ("Iterating backwards through binary logs, looking for the last binary log that contains a Previous_gtids_log_event."));
    // Iterate over all files in reverse order until we find one that
    // contains a Previous_gtids_log_event.
    rit= filename_list.rbegin();
    bool got_gtids= false;
    reached_first_file= (rit == filename_list.rend());
    DBUG_PRINT("info", ("filename='%s' reached_first_file=%d",
                        rit->c_str(), reached_first_file));
    while (!got_gtids && !reached_first_file)
    {
      const char *filename= rit->c_str();
      rit++;
      reached_first_file= (rit == filename_list.rend());
      DBUG_PRINT("info", ("filename='%s' got_gtids=%d reached_first_file=%d",
                          filename, got_gtids, reached_first_file));
      switch (read_gtids_from_binlog(filename, all_gtids,
                                     reached_first_file ? lost_gtids : NULL,
                                     verify_checksum))
      {
      case ERROR:
        error= 1;
        goto end;
      case GOT_GTIDS:
      case GOT_PREVIOUS_GTIDS:
        got_gtids= true;
        /*FALLTHROUGH*/
      case NO_GTIDS:
      case TRUNCATED:
        break;
      }
    }
  }
  if (lost_gtids != NULL && !reached_first_file)
  {
    DBUG_PRINT("info", ("Iterating forwards through binary logs, looking for the first binary log that contains a Previous_gtids_log_event."));
    for (it= filename_list.begin(); it != filename_list.end(); it++)
    {
      const char *filename= it->c_str();
      DBUG_PRINT("info", ("filename='%s'", filename));
      switch (read_gtids_from_binlog(filename, NULL, lost_gtids,
                                     verify_checksum))
      {
      case ERROR:
        error= 1;
        /*FALLTHROUGH*/
      case GOT_GTIDS:
        goto end;
      case GOT_PREVIOUS_GTIDS:
      case NO_GTIDS:
      case TRUNCATED:
        break;
      }
    }
  }
end:
  if (all_gtids)
    all_gtids->dbug_print("all_gtids");
  if (lost_gtids)
    lost_gtids->dbug_print("lost_gtids");
  if (need_lock)
  {
    global_sid_lock->unlock();
    mysql_mutex_unlock(&LOCK_index);
    if (all_gtids != NULL)
      mysql_mutex_unlock(&LOCK_log);
  }
  filename_list.clear();
  DBUG_PRINT("info", ("returning %d", error));
  DBUG_RETURN(error != 0 ? true : false);
}


bool MYSQL_BIN_LOG::open_binlog(const char *log_name,
                                const char *new_name,
                                enum cache_type io_cache_type_arg,
                                ulong max_size_arg,
                                bool null_created_arg,
                                bool need_lock_index,
                                bool need_sid_lock,
                                Format_description_log_event *extra_description_event)
{
  File file= -1;

  // lock_index must be acquired *before* sid_lock.
  DBUG_ASSERT(need_sid_lock || !need_lock_index);
  DBUG_ENTER("MYSQL_BIN_LOG::open_binlog(const char *, ...)");
  DBUG_PRINT("enter",("name: %s", log_name));

  if (init_and_set_log_file_name(log_name, new_name, LOG_BIN,
                                 io_cache_type_arg))
  {
    sql_print_error("MYSQL_BIN_LOG::open failed to generate new file name.");
    DBUG_RETURN(1);
  }

#ifdef HAVE_REPLICATION
  if (open_purge_index_file(TRUE) ||
      register_create_index_entry(log_file_name) ||
      sync_purge_index_file() ||
      DBUG_EVALUATE_IF("fault_injection_registering_index", 1, 0))
  {
    DBUG_EXECUTE_IF("fault_injection_registering_index", {
      if (my_b_inited(&purge_index_file))
      {
        end_io_cache(&purge_index_file);
        my_close(purge_index_file.file, MYF(0));
      }
    });

    sql_print_error("MYSQL_BIN_LOG::open failed to sync the index file.");
    DBUG_RETURN(1);
  }
  DBUG_EXECUTE_IF("crash_create_non_critical_before_update_index", DBUG_SUICIDE(););
#endif

  write_error= 0;

  /* open the main log file */
  if (MYSQL_LOG::open(
#ifdef HAVE_PSI_INTERFACE
                      m_key_file_log,
#endif
                      log_name, LOG_BIN, new_name, io_cache_type_arg))
  {
#ifdef HAVE_REPLICATION
    close_purge_index_file();
#endif
    DBUG_RETURN(1);                            /* all warnings issued */
  }

  max_size= max_size_arg;

  open_count++;

  bool write_file_name_to_index_file=0;

  /* This must be before goto err. */
  Format_description_log_event s(BINLOG_VERSION);

  if (!my_b_filelength(&log_file))
  {
    /*
      The binary log file was empty (probably newly created)
      This is the normal case and happens when the user doesn't specify
      an extension for the binary log files.
      In this case we write a standard header to it.
    */
    if (my_b_safe_write(&log_file, (uchar*) BINLOG_MAGIC,
                        BIN_LOG_HEADER_SIZE))
      goto err;
    bytes_written+= BIN_LOG_HEADER_SIZE;
    write_file_name_to_index_file= 1;
  }

  /*
    don't set LOG_EVENT_BINLOG_IN_USE_F for SEQ_READ_APPEND io_cache
    as we won't be able to reset it later
  */
  if (io_cache_type == WRITE_CACHE)
    s.flags |= LOG_EVENT_BINLOG_IN_USE_F;
  s.checksum_alg= is_relay_log ?
    /* relay-log */
    /* inherit master's A descriptor if one has been received */
    (relay_log_checksum_alg=
     (relay_log_checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF) ?
     relay_log_checksum_alg :
     /* otherwise use slave's local preference of RL events verification */
     (opt_slave_sql_verify_checksum == 0) ?
     (uint8) BINLOG_CHECKSUM_ALG_OFF : binlog_checksum_options):
    /* binlog */
    binlog_checksum_options;
  DBUG_ASSERT(s.checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF);
  if (!s.is_valid())
    goto err;
  s.dont_set_created= null_created_arg;
  /* Set LOG_EVENT_RELAY_LOG_F flag for relay log's FD */
  if (is_relay_log)
    s.set_relay_log_event();
  if (s.write(&log_file))
    goto err;
  bytes_written+= s.data_written;
  /*
    We need to revisit this code and improve it.
    See further comments in the mysqld.
    /Alfranio
  */
  if (current_thd && gtid_mode > 0)
  {
    if (need_sid_lock)
      global_sid_lock->wrlock();
    else
      global_sid_lock->assert_some_wrlock();
    Previous_gtids_log_event prev_gtids_ev(previous_gtid_set);
    if (need_sid_lock)
      global_sid_lock->unlock();
    prev_gtids_ev.checksum_alg= s.checksum_alg;
    if (prev_gtids_ev.write(&log_file))
      goto err;
    bytes_written+= prev_gtids_ev.data_written;
  }
  if (extra_description_event &&
      extra_description_event->binlog_version>=4)
  {
    /*
      This is a relay log written to by the I/O slave thread.
      Write the event so that others can later know the format of this relay
      log.
      Note that this event is very close to the original event from the
      master (it has binlog version of the master, event types of the
      master), so this is suitable to parse the next relay log's event. It
      has been produced by
      Format_description_log_event::Format_description_log_event(char* buf,).
      Why don't we want to write the mi_description_event if this
      event is for format<4 (3.23 or 4.x): this is because in that case, the
      mi_description_event describes the data received from the
      master, but not the data written to the relay log (*conversion*),
      which is in format 4 (slave's).
    */
    /*
      Set 'created' to 0, so that in next relay logs this event does not
      trigger cleaning actions on the slave in
      Format_description_log_event::apply_event_impl().
    */
    extra_description_event->created= 0;
    /* Don't set log_pos in event header */
    extra_description_event->set_artificial_event();

    if (extra_description_event->write(&log_file))
      goto err;
    bytes_written+= extra_description_event->data_written;
  }
  if (flush_io_cache(&log_file) ||
      mysql_file_sync(log_file.file, MYF(MY_WME)))
    goto err;
  
  if (write_file_name_to_index_file)
  {
#ifdef HAVE_REPLICATION
    DBUG_EXECUTE_IF("crash_create_critical_before_update_index", DBUG_SUICIDE(););
#endif

    DBUG_ASSERT(my_b_inited(&index_file) != 0);

    /*
      The new log file name is appended into crash safe index file after
      all the content of index file is copyed into the crash safe index
      file. Then move the crash safe index file to index file.
    */
    if (DBUG_EVALUATE_IF("fault_injection_updating_index", 1, 0) ||
        add_log_to_index((uchar*) log_file_name, strlen(log_file_name),
                         need_lock_index))
      goto err;

#ifdef HAVE_REPLICATION
    DBUG_EXECUTE_IF("crash_create_after_update_index", DBUG_SUICIDE(););
#endif
  }

  log_state= LOG_OPENED;

#ifdef HAVE_REPLICATION
  close_purge_index_file();
#endif

  DBUG_RETURN(0);

err:
#ifdef HAVE_REPLICATION
  if (is_inited_purge_index_file())
    purge_index_entry(NULL, NULL, need_lock_index);
  close_purge_index_file();
#endif
  sql_print_error("Could not use %s for logging (error %d). \
Turning logging off for the whole duration of the MySQL server process. \
To turn it on again: fix the cause, \
shutdown the MySQL server and restart it.", name, errno);
  if (file >= 0)
    mysql_file_close(file, MYF(0));
  end_io_cache(&log_file);
  end_io_cache(&index_file);
  my_free(name);
  name= NULL;
  log_state= LOG_CLOSED;
  DBUG_RETURN(1);
}


int MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file(bool need_lock_index)
{
  int error= 0;
  File fd= -1;
  DBUG_ENTER("MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file");

  if (need_lock_index)
    mysql_mutex_lock(&LOCK_index);
  else
    mysql_mutex_assert_owner(&LOCK_index);

  if (my_b_inited(&index_file))
  {
    end_io_cache(&index_file);
    if (mysql_file_close(index_file.file, MYF(0)) < 0)
    {
      error= -1;
      sql_print_error("MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file "
                      "failed to close the index file.");
      goto err;
    }
    mysql_file_delete(key_file_binlog_index, index_file_name, MYF(MY_WME));
  }

  DBUG_EXECUTE_IF("crash_create_before_rename_index_file", DBUG_SUICIDE(););
  if (my_rename(crash_safe_index_file_name, index_file_name, MYF(MY_WME)))
  {
    error= -1;
    sql_print_error("MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file "
                    "failed to move crash_safe_index_file to index file.");
    goto err;
  }
  DBUG_EXECUTE_IF("crash_create_after_rename_index_file", DBUG_SUICIDE(););

  if ((fd= mysql_file_open(key_file_binlog_index,
                           index_file_name,
                           O_RDWR | O_CREAT | O_BINARY,
                           MYF(MY_WME))) < 0 ||
           mysql_file_sync(fd, MYF(MY_WME)) ||
           init_io_cache(&index_file, fd, IO_SIZE, READ_CACHE,
                         mysql_file_seek(fd, 0L, MY_SEEK_END, MYF(0)),
                                         0, MYF(MY_WME | MY_WAIT_IF_FULL)))
  {
    error= -1;
    sql_print_error("MYSQL_BIN_LOG::move_crash_safe_index_file_to_index_file "
                    "failed to open the index file.");
    goto err;
  }

err:
  if (need_lock_index)
    mysql_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::add_log_to_index(uchar* log_name,
                                    int log_name_len, bool need_lock_index)
{
  DBUG_ENTER("MYSQL_BIN_LOG::add_log_to_index");

  if (open_crash_safe_index_file())
  {
    sql_print_error("MYSQL_BIN_LOG::add_log_to_index failed to "
                    "open the crash safe index file.");
    goto err;
  }

  if (copy_file(&index_file, &crash_safe_index_file, 0))
  {
    sql_print_error("MYSQL_BIN_LOG::add_log_to_index failed to "
                    "copy index file to crash safe index file.");
    goto err;
  }

  if (my_b_write(&crash_safe_index_file, log_name, log_name_len) ||
      my_b_write(&crash_safe_index_file, (uchar*) "\n", 1) ||
      flush_io_cache(&crash_safe_index_file) ||
      mysql_file_sync(crash_safe_index_file.file, MYF(MY_WME)))
  {
    sql_print_error("MYSQL_BIN_LOG::add_log_to_index failed to "
                    "append log file name: %s, to crash "
                    "safe index file.", log_name);
    goto err;
  }

  if (close_crash_safe_index_file())
  {
    sql_print_error("MYSQL_BIN_LOG::add_log_to_index failed to "
                    "close the crash safe index file.");
    goto err;
  }

  if (move_crash_safe_index_file_to_index_file(need_lock_index))
  {
    sql_print_error("MYSQL_BIN_LOG::add_log_to_index failed to "
                    "move crash safe index file to index file.");
    goto err;
  }

  DBUG_RETURN(0);

err:
  DBUG_RETURN(-1);
}

int MYSQL_BIN_LOG::get_current_log(LOG_INFO* linfo)
{
  mysql_mutex_lock(&LOCK_log);
  int ret = raw_get_current_log(linfo);
  mysql_mutex_unlock(&LOCK_log);
  return ret;
}

int MYSQL_BIN_LOG::raw_get_current_log(LOG_INFO* linfo)
{
  strmake(linfo->log_file_name, log_file_name, sizeof(linfo->log_file_name)-1);
  linfo->pos = my_b_tell(&log_file);
  return 0;
}

bool MYSQL_BIN_LOG::check_write_error(THD *thd)
{
  DBUG_ENTER("MYSQL_BIN_LOG::check_write_error");

  bool checked= FALSE;

  if (!thd->is_error())
    DBUG_RETURN(checked);

  switch (thd->get_stmt_da()->sql_errno())
  {
    case ER_TRANS_CACHE_FULL:
    case ER_STMT_CACHE_FULL:
    case ER_ERROR_ON_WRITE:
    case ER_BINLOG_LOGGING_IMPOSSIBLE:
      checked= TRUE;
    break;
  }
  DBUG_PRINT("return", ("checked: %s", YESNO(checked)));
  DBUG_RETURN(checked);
}

void MYSQL_BIN_LOG::set_write_error(THD *thd, bool is_transactional)
{
  DBUG_ENTER("MYSQL_BIN_LOG::set_write_error");

  write_error= 1;

  if (check_write_error(thd))
    DBUG_VOID_RETURN;

  if (my_errno == EFBIG)
  {
    if (is_transactional)
    {
      my_message(ER_TRANS_CACHE_FULL, ER(ER_TRANS_CACHE_FULL), MYF(MY_WME));
    }
    else
    {
      my_message(ER_STMT_CACHE_FULL, ER(ER_STMT_CACHE_FULL), MYF(MY_WME));
    }
  }
  else
  {
    char errbuf[MYSYS_STRERROR_SIZE];
    my_error(ER_ERROR_ON_WRITE, MYF(MY_WME), name,
             errno, my_strerror(errbuf, sizeof(errbuf), errno));
  }

  DBUG_VOID_RETURN;
}

int MYSQL_BIN_LOG::find_log_pos(LOG_INFO *linfo, const char *log_name,
                                bool need_lock_index)
{
  int error= 0;
  char *full_fname= linfo->log_file_name;
  char full_log_name[FN_REFLEN], fname[FN_REFLEN];
  uint log_name_len= 0, fname_len= 0;
  DBUG_ENTER("find_log_pos");
  full_log_name[0]= full_fname[0]= 0;

  /*
    Mutex needed because we need to make sure the file pointer does not
    move from under our feet
  */
  if (need_lock_index)
    mysql_mutex_lock(&LOCK_index);
  else
    mysql_mutex_assert_owner(&LOCK_index);

  // extend relative paths for log_name to be searched
  if (log_name)
  {
    if(normalize_binlog_name(full_log_name, log_name, is_relay_log))
    {
      error= LOG_INFO_EOF;
      goto end;
    }
  }

  log_name_len= log_name ? (uint) strlen(full_log_name) : 0;
  DBUG_PRINT("enter", ("log_name: %s, full_log_name: %s", 
                       log_name ? log_name : "NULL", full_log_name));

  /* As the file is flushed, we can't get an error here */
  my_b_seek(&index_file, (my_off_t) 0);

  for (;;)
  {
    uint length;
    my_off_t offset= my_b_tell(&index_file);

    DBUG_EXECUTE_IF("simulate_find_log_pos_error",
                    error=  LOG_INFO_EOF; break;);
    /* If we get 0 or 1 characters, this is the end of the file */
    if ((length= my_b_gets(&index_file, fname, FN_REFLEN)) <= 1)
    {
      /* Did not find the given entry; Return not found or error */
      error= !index_file.error ? LOG_INFO_EOF : LOG_INFO_IO;
      break;
    }

    // extend relative paths and match against full path
    if (normalize_binlog_name(full_fname, fname, is_relay_log))
    {
      error= LOG_INFO_EOF;
      break;
    }
    fname_len= (uint) strlen(full_fname);

    // if the log entry matches, null string matching anything
    if (!log_name ||
       (log_name_len == fname_len-1 && full_fname[log_name_len] == '\n' &&
        !memcmp(full_fname, full_log_name, log_name_len)))
    {
      DBUG_PRINT("info", ("Found log file entry"));
      full_fname[fname_len-1]= 0;                      // remove last \n
      linfo->index_file_start_offset= offset;
      linfo->index_file_offset = my_b_tell(&index_file);
      break;
    }
    linfo->entry_index++;
  }

end:  
  if (need_lock_index)
    mysql_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::find_next_log(LOG_INFO* linfo, bool need_lock_index)
{
  int error= 0;
  uint length;
  char fname[FN_REFLEN];
  char *full_fname= linfo->log_file_name;

  if (need_lock_index)
    mysql_mutex_lock(&LOCK_index);
  else
    mysql_mutex_assert_owner(&LOCK_index);

  /* As the file is flushed, we can't get an error here */
  my_b_seek(&index_file, linfo->index_file_offset);

  linfo->index_file_start_offset= linfo->index_file_offset;
  if ((length=my_b_gets(&index_file, fname, FN_REFLEN)) <= 1)
  {
    error = !index_file.error ? LOG_INFO_EOF : LOG_INFO_IO;
    goto err;
  }

  if (fname[0] != 0)
  {
    if(normalize_binlog_name(full_fname, fname, is_relay_log))
    {
      error= LOG_INFO_EOF;
      goto err;
    }
    length= strlen(full_fname);
  }

  full_fname[length-1]= 0;                     // kill \n
  linfo->index_file_offset= my_b_tell(&index_file);

err:
  if (need_lock_index)
    mysql_mutex_unlock(&LOCK_index);
  return error;
}


bool MYSQL_BIN_LOG::reset_logs(THD* thd)
{
  LOG_INFO linfo;
  bool error=0;
  int err;
  const char* save_name;
  DBUG_ENTER("reset_logs");

  /*
    Flush logs for storage engines, so that the last transaction
    is fsynced inside storage engines.
  */
  if (ha_flush_logs(NULL))
    DBUG_RETURN(1);

  ha_reset_logs(thd);

  /*
    The following mutex is needed to ensure that no threads call
    'delete thd' as we would then risk missing a 'rollback' from this
    thread. If the transaction involved MyISAM tables, it should go
    into binlog even on rollback.
  */
  mysql_mutex_lock(&LOCK_thread_count);

  /*
    We need to get both locks to be sure that no one is trying to
    write to the index log file.
  */
  mysql_mutex_lock(&LOCK_log);
  mysql_mutex_lock(&LOCK_index);

  global_sid_lock->wrlock();

  /* Save variables so that we can reopen the log */
  save_name=name;
  name=0;                                       // Protect against free
  close(LOG_CLOSE_TO_BE_OPENED);

  /*
    First delete all old log files and then update the index file.
    As we first delete the log files and do not use sort of logging,
    a crash may lead to an inconsistent state where the index has
    references to non-existent files.

    We need to invert the steps and use the purge_index_file methods
    in order to make the operation safe.
  */

  if ((err= find_log_pos(&linfo, NullS, false/*need_lock_index=false*/)) != 0)
  {
    uint errcode= purge_log_get_error_code(err);
    sql_print_error("Failed to locate old binlog or relay log files");
    my_message(errcode, ER(errcode), MYF(0));
    error= 1;
    goto err;
  }

  for (;;)
  {
    if ((error= my_delete_allow_opened(linfo.log_file_name, MYF(0))) != 0)
    {
      if (my_errno == ENOENT) 
      {
        push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
                            ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                            linfo.log_file_name);
        sql_print_information("Failed to delete file '%s'",
                              linfo.log_file_name);
        my_errno= 0;
        error= 0;
      }
      else
      {
        push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
                            ER_BINLOG_PURGE_FATAL_ERR,
                            "a problem with deleting %s; "
                            "consider examining correspondence "
                            "of your binlog index file "
                            "to the actual binlog files",
                            linfo.log_file_name);
        error= 1;
        goto err;
      }
    }
    if (find_next_log(&linfo, false/*need_lock_index=false*/))
      break;
  }

  /* Start logging with a new file */
  close(LOG_CLOSE_INDEX | LOG_CLOSE_TO_BE_OPENED);
  if ((error= my_delete_allow_opened(index_file_name, MYF(0)))) // Reset (open will update)
  {
    if (my_errno == ENOENT) 
    {
      push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                          index_file_name);
      sql_print_information("Failed to delete file '%s'",
                            index_file_name);
      my_errno= 0;
      error= 0;
    }
    else
    {
      push_warning_printf(current_thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_BINLOG_PURGE_FATAL_ERR,
                          "a problem with deleting %s; "
                          "consider examining correspondence "
                          "of your binlog index file "
                          "to the actual binlog files",
                          index_file_name);
      error= 1;
      goto err;
    }
  }

#ifdef HAVE_REPLICATION
  if (is_relay_log)
  {
    DBUG_ASSERT(active_mi != NULL);
    DBUG_ASSERT(active_mi->rli != NULL);
    (const_cast<Gtid_set *>(active_mi->rli->get_gtid_set()))->clear();
  }
  else
  {
    gtid_state->clear();
    // don't clear global_sid_map because it's used by the relay log too
    if (gtid_state->init() != 0)
      goto err;
  }
#endif

  if (!open_index_file(index_file_name, 0, false/*need_lock_index=false*/))
    if ((error= open_binlog(save_name, 0, io_cache_type,
                            max_size, false,
                            false/*need_lock_index=false*/,
                            false/*need_sid_lock=false*/,
                            NULL)))
      goto err;
  my_free((void *) save_name);

err:
  if (error == 1)
    name= const_cast<char*>(save_name);
  global_sid_lock->unlock();
  mysql_mutex_unlock(&LOCK_thread_count);
  mysql_mutex_unlock(&LOCK_index);
  mysql_mutex_unlock(&LOCK_log);
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::set_crash_safe_index_file_name(const char *base_file_name)
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::set_crash_safe_index_file_name");
  if (fn_format(crash_safe_index_file_name, base_file_name, mysql_data_home,
                ".index_crash_safe", MYF(MY_UNPACK_FILENAME | MY_SAFE_PATH |
                                         MY_REPLACE_EXT)) == NULL)
  {
    error= 1;
    sql_print_error("MYSQL_BIN_LOG::set_crash_safe_index_file_name failed "
                    "to set file name.");
  }
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::open_crash_safe_index_file()
{
  int error= 0;
  File file= -1;

  DBUG_ENTER("MYSQL_BIN_LOG::open_crash_safe_index_file");

  if (!my_b_inited(&crash_safe_index_file))
  {
    if ((file= my_open(crash_safe_index_file_name, O_RDWR | O_CREAT | O_BINARY,
                       MYF(MY_WME | ME_WAITTANG))) < 0  ||
        init_io_cache(&crash_safe_index_file, file, IO_SIZE, WRITE_CACHE,
                      0, 0, MYF(MY_WME | MY_NABP | MY_WAIT_IF_FULL)))
    {
      error= 1;
      sql_print_error("MYSQL_BIN_LOG::open_crash_safe_index_file failed "
                      "to open temporary index file.");
    }
  }
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::close_crash_safe_index_file()
{
  int error= 0;

  DBUG_ENTER("MYSQL_BIN_LOG::close_crash_safe_index_file");

  if (my_b_inited(&crash_safe_index_file))
  {
    end_io_cache(&crash_safe_index_file);
    error= my_close(crash_safe_index_file.file, MYF(0));
  }
  memset(&crash_safe_index_file, 0, sizeof(crash_safe_index_file));

  DBUG_RETURN(error);
}


#ifdef HAVE_REPLICATION

int MYSQL_BIN_LOG::purge_first_log(Relay_log_info* rli, bool included)
{
  int error;
  char *to_purge_if_included= NULL;
  DBUG_ENTER("purge_first_log");

  DBUG_ASSERT(current_thd->system_thread == SYSTEM_THREAD_SLAVE_SQL);
  DBUG_ASSERT(is_relay_log);
  DBUG_ASSERT(is_open());
  DBUG_ASSERT(rli->slave_running == 1);
  DBUG_ASSERT(!strcmp(rli->linfo.log_file_name,rli->get_event_relay_log_name()));

  mysql_mutex_assert_owner(&rli->data_lock);

  mysql_mutex_lock(&LOCK_index);
  to_purge_if_included= my_strdup(rli->get_group_relay_log_name(), MYF(0));

  /*
    Read the next log file name from the index file and pass it back to
    the caller.
  */
  if((error=find_log_pos(&rli->linfo, rli->get_event_relay_log_name(),
                         false/*need_lock_index=false*/)) ||
     (error=find_next_log(&rli->linfo, false/*need_lock_index=false*/)))
  {
    char buff[22];
    sql_print_error("next log error: %d  offset: %s  log: %s included: %d",
                    error,
                    llstr(rli->linfo.index_file_offset,buff),
                    rli->get_event_relay_log_name(),
                    included);
    goto err;
  }

  /*
    Reset rli's coordinates to the current log.
  */
  rli->set_event_relay_log_pos(BIN_LOG_HEADER_SIZE);
  rli->set_event_relay_log_name(rli->linfo.log_file_name);

  /*
    If we removed the rli->group_relay_log_name file,
    we must update the rli->group* coordinates, otherwise do not touch it as the
    group's execution is not finished (e.g. COMMIT not executed)
  */
  if (included)
  {
    rli->set_group_relay_log_pos(BIN_LOG_HEADER_SIZE);
    rli->set_group_relay_log_name(rli->linfo.log_file_name);
    rli->notify_group_relay_log_name_update();
  }

  /* Store where we are in the new file for the execution thread */
  rli->flush_info(TRUE);

  DBUG_EXECUTE_IF("crash_before_purge_logs", DBUG_SUICIDE(););

  mysql_mutex_lock(&rli->log_space_lock);
  rli->relay_log.purge_logs(to_purge_if_included, included,
                            false/*need_lock_index=false*/,
                            false/*need_update_threads=false*/,
                            &rli->log_space_total, true);
  // Tell the I/O thread to take the relay_log_space_limit into account
  rli->ignore_log_space_limit= 0;
  mysql_mutex_unlock(&rli->log_space_lock);

  /*
    Ok to broadcast after the critical region as there is no risk of
    the mutex being destroyed by this thread later - this helps save
    context switches
  */
  mysql_cond_broadcast(&rli->log_space_cond);

  /*
   * Need to update the log pos because purge logs has been called 
   * after fetching initially the log pos at the begining of the method.
   */
  if((error=find_log_pos(&rli->linfo, rli->get_event_relay_log_name(),
                         false/*need_lock_index=false*/)))
  {
    char buff[22];
    sql_print_error("next log error: %d  offset: %s  log: %s included: %d",
                    error,
                    llstr(rli->linfo.index_file_offset,buff),
                    rli->get_group_relay_log_name(),
                    included);
    goto err;
  }

  /* If included was passed, rli->linfo should be the first entry. */
  DBUG_ASSERT(!included || rli->linfo.index_file_start_offset == 0);

err:
  my_free(to_purge_if_included);
  mysql_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}


int MYSQL_BIN_LOG::remove_logs_from_index(LOG_INFO* log_info, bool need_update_threads)
{
  if (open_crash_safe_index_file())
  {
    sql_print_error("MYSQL_BIN_LOG::remove_logs_from_index failed to "
                    "open the crash safe index file.");
    goto err;
  }

  if (copy_file(&index_file, &crash_safe_index_file,
                log_info->index_file_start_offset))
  {
    sql_print_error("MYSQL_BIN_LOG::remove_logs_from_index failed to "
                    "copy index file to crash safe index file.");
    goto err;
  }

  if (close_crash_safe_index_file())
  {
    sql_print_error("MYSQL_BIN_LOG::remove_logs_from_index failed to "
                    "close the crash safe index file.");
    goto err;
  }
  DBUG_EXECUTE_IF("fault_injection_copy_part_file", DBUG_SUICIDE(););

  if (move_crash_safe_index_file_to_index_file(false/*need_lock_index=false*/))
  {
    sql_print_error("MYSQL_BIN_LOG::remove_logs_from_index failed to "
                    "move crash safe index file to index file.");
    goto err;
  }

  // now update offsets in index file for running threads
  if (need_update_threads)
    adjust_linfo_offsets(log_info->index_file_start_offset);
  return 0;

err:
  return LOG_INFO_IO;
}

int MYSQL_BIN_LOG::purge_logs(const char *to_log,
                              bool included,
                              bool need_lock_index,
                              bool need_update_threads,
                              ulonglong *decrease_log_space,
                              bool auto_purge)
{
  int error= 0, no_of_log_files_to_purge= 0, no_of_log_files_purged= 0;
  int no_of_threads_locking_log= 0;
  bool exit_loop= 0;
  LOG_INFO log_info;
  THD *thd= current_thd;
  DBUG_ENTER("purge_logs");
  DBUG_PRINT("info",("to_log= %s",to_log));

  if (need_lock_index)
    mysql_mutex_lock(&LOCK_index);
  else
    mysql_mutex_assert_owner(&LOCK_index);
  if ((error=find_log_pos(&log_info, to_log, false/*need_lock_index=false*/))) 
  {
    sql_print_error("MYSQL_BIN_LOG::purge_logs was called with file %s not "
                    "listed in the index.", to_log);
    goto err;
  }

  no_of_log_files_to_purge= log_info.entry_index;

  if ((error= open_purge_index_file(TRUE)))
  {
    sql_print_error("MYSQL_BIN_LOG::purge_logs failed to sync the index file.");
    goto err;
  }

  /*
    File name exists in index file; delete until we find this file
    or a file that is used.
  */
  if ((error=find_log_pos(&log_info, NullS, false/*need_lock_index=false*/)))
    goto err;

  while ((strcmp(to_log,log_info.log_file_name) || (exit_loop=included)))
  {
    if(is_active(log_info.log_file_name))
    {
      if(!auto_purge)
        push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                            ER_WARN_PURGE_LOG_IS_ACTIVE,
                            ER(ER_WARN_PURGE_LOG_IS_ACTIVE),
                            log_info.log_file_name);
      break;
    }

    if ((no_of_threads_locking_log= log_in_use(log_info.log_file_name)))
    {
      if(!auto_purge)
        push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                            ER_WARN_PURGE_LOG_IN_USE,
                            ER(ER_WARN_PURGE_LOG_IN_USE),
                            log_info.log_file_name,  no_of_threads_locking_log,
                            no_of_log_files_purged, no_of_log_files_to_purge);
      break;
    }
    no_of_log_files_purged++;

    if ((error= register_purge_index_entry(log_info.log_file_name)))
    {
      sql_print_error("MYSQL_BIN_LOG::purge_logs failed to copy %s to register file.",
                      log_info.log_file_name);
      goto err;
    }

    if (find_next_log(&log_info, false/*need_lock_index=false*/) || exit_loop)
      break;
  }

  DBUG_EXECUTE_IF("crash_purge_before_update_index", DBUG_SUICIDE(););

  if ((error= sync_purge_index_file()))
  {
    sql_print_error("MYSQL_BIN_LOG::purge_logs failed to flush register file.");
    goto err;
  }

  /* We know how many files to delete. Update index file. */
  if ((error=remove_logs_from_index(&log_info, need_update_threads)))
  {
    sql_print_error("MYSQL_BIN_LOG::purge_logs failed to update the index file");
    goto err;
  }

  // Update gtid_state->lost_gtids
  if (gtid_mode > 0 && !is_relay_log)
  {
    global_sid_lock->wrlock();
    error= init_gtid_sets(NULL,
                       const_cast<Gtid_set *>(gtid_state->get_lost_gtids()),
                       opt_master_verify_checksum,
                       false/*false=don't need lock*/);
    global_sid_lock->unlock();
    if (error)
      goto err;
  }

  DBUG_EXECUTE_IF("crash_purge_critical_after_update_index", DBUG_SUICIDE(););

err:

  int error_index= 0, close_error_index= 0;
  /* Read each entry from purge_index_file and delete the file. */
  if (is_inited_purge_index_file() &&
      (error_index= purge_index_entry(thd, decrease_log_space, false/*need_lock_index=false*/)))
    sql_print_error("MYSQL_BIN_LOG::purge_logs failed to process registered files"
                    " that would be purged.");

  close_error_index= close_purge_index_file();

  DBUG_EXECUTE_IF("crash_purge_non_critical_after_update_index", DBUG_SUICIDE(););

  if (need_lock_index)
    mysql_mutex_unlock(&LOCK_index);

  /*
    Error codes from purge logs take precedence.
    Then error codes from purging the index entry.
    Finally, error codes from closing the purge index file.
  */
  error= error ? error : (error_index ? error_index :
                          close_error_index);

  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::set_purge_index_file_name(const char *base_file_name)
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::set_purge_index_file_name");
  if (fn_format(purge_index_file_name, base_file_name, mysql_data_home,
                ".~rec~", MYF(MY_UNPACK_FILENAME | MY_SAFE_PATH |
                              MY_REPLACE_EXT)) == NULL)
  {
    error= 1;
    sql_print_error("MYSQL_BIN_LOG::set_purge_index_file_name failed to set "
                      "file name.");
  }
  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::open_purge_index_file(bool destroy)
{
  int error= 0;
  File file= -1;

  DBUG_ENTER("MYSQL_BIN_LOG::open_purge_index_file");

  if (destroy)
    close_purge_index_file();

  if (!my_b_inited(&purge_index_file))
  {
    if ((file= my_open(purge_index_file_name, O_RDWR | O_CREAT | O_BINARY,
                       MYF(MY_WME | ME_WAITTANG))) < 0  ||
        init_io_cache(&purge_index_file, file, IO_SIZE,
                      (destroy ? WRITE_CACHE : READ_CACHE),
                      0, 0, MYF(MY_WME | MY_NABP | MY_WAIT_IF_FULL)))
    {
      error= 1;
      sql_print_error("MYSQL_BIN_LOG::open_purge_index_file failed to open register "
                      " file.");
    }
  }
  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::close_purge_index_file()
{
  int error= 0;

  DBUG_ENTER("MYSQL_BIN_LOG::close_purge_index_file");

  if (my_b_inited(&purge_index_file))
  {
    end_io_cache(&purge_index_file);
    error= my_close(purge_index_file.file, MYF(0));
  }
  my_delete(purge_index_file_name, MYF(0));
  memset(&purge_index_file, 0, sizeof(purge_index_file));

  DBUG_RETURN(error);
}

bool MYSQL_BIN_LOG::is_inited_purge_index_file()
{
  DBUG_ENTER("MYSQL_BIN_LOG::is_inited_purge_index_file");
  DBUG_RETURN (my_b_inited(&purge_index_file));
}

int MYSQL_BIN_LOG::sync_purge_index_file()
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::sync_purge_index_file");

  if ((error= flush_io_cache(&purge_index_file)) ||
      (error= my_sync(purge_index_file.file, MYF(MY_WME))))
    DBUG_RETURN(error);

  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::register_purge_index_entry(const char *entry)
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::register_purge_index_entry");

  if ((error=my_b_write(&purge_index_file, (const uchar*)entry, strlen(entry))) ||
      (error=my_b_write(&purge_index_file, (const uchar*)"\n", 1)))
    DBUG_RETURN (error);

  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::register_create_index_entry(const char *entry)
{
  DBUG_ENTER("MYSQL_BIN_LOG::register_create_index_entry");
  DBUG_RETURN(register_purge_index_entry(entry));
}

int MYSQL_BIN_LOG::purge_index_entry(THD *thd, ulonglong *decrease_log_space,
                                     bool need_lock_index)
{
  MY_STAT s;
  int error= 0;
  LOG_INFO log_info;
  LOG_INFO check_log_info;

  DBUG_ENTER("MYSQL_BIN_LOG:purge_index_entry");

  DBUG_ASSERT(my_b_inited(&purge_index_file));

  if ((error=reinit_io_cache(&purge_index_file, READ_CACHE, 0, 0, 0)))
  {
    sql_print_error("MYSQL_BIN_LOG::purge_index_entry failed to reinit register file "
                    "for read");
    goto err;
  }

  for (;;)
  {
    uint length;

    if ((length=my_b_gets(&purge_index_file, log_info.log_file_name,
                          FN_REFLEN)) <= 1)
    {
      if (purge_index_file.error)
      {
        error= purge_index_file.error;
        sql_print_error("MYSQL_BIN_LOG::purge_index_entry error %d reading from "
                        "register file.", error);
        goto err;
      }

      /* Reached EOF */
      break;
    }

    /* Get rid of the trailing '\n' */
    log_info.log_file_name[length-1]= 0;

    if (!mysql_file_stat(m_key_file_log, log_info.log_file_name, &s, MYF(0)))
    {
      if (my_errno == ENOENT) 
      {
        /*
          It's not fatal if we can't stat a log file that does not exist;
          If we could not stat, we won't delete.
        */
        if (thd)
        {
          push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                              ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                              log_info.log_file_name);
        }
        sql_print_information("Failed to execute mysql_file_stat on file '%s'",
                              log_info.log_file_name);
        my_errno= 0;
      }
      else
      {
        /*
          Other than ENOENT are fatal
        */
        if (thd)
        {
          push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                              ER_BINLOG_PURGE_FATAL_ERR,
                              "a problem with getting info on being purged %s; "
                              "consider examining correspondence "
                              "of your binlog index file "
                              "to the actual binlog files",
                              log_info.log_file_name);
        }
        else
        {
          sql_print_information("Failed to delete log file '%s'; "
                                "consider examining correspondence "
                                "of your binlog index file "
                                "to the actual binlog files",
                                log_info.log_file_name);
        }
        error= LOG_INFO_FATAL;
        goto err;
      }
    }
    else
    {
      if ((error= find_log_pos(&check_log_info, log_info.log_file_name,
                               need_lock_index)))
      {
        if (error != LOG_INFO_EOF)
        {
          if (thd)
          {
            push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                                ER_BINLOG_PURGE_FATAL_ERR,
                                "a problem with deleting %s and "
                                "reading the binlog index file",
                                log_info.log_file_name);
          }
          else
          {
            sql_print_information("Failed to delete file '%s' and "
                                  "read the binlog index file",
                                  log_info.log_file_name);
          }
          goto err;
        }
           
        error= 0;
        if (!need_lock_index)
        {
          /*
            This is to avoid triggering an error in NDB.

            @todo: This is weird, what does NDB errors have to do with
            need_lock_index? Explain better or refactor /Sven
          */
          ha_binlog_index_purge_file(current_thd, log_info.log_file_name);
        }

        DBUG_PRINT("info",("purging %s",log_info.log_file_name));
        if (!my_delete(log_info.log_file_name, MYF(0)))
        {
          if (decrease_log_space)
            *decrease_log_space-= s.st_size;
        }
        else
        {
          if (my_errno == ENOENT)
          {
            if (thd)
            {
              push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                                  ER_LOG_PURGE_NO_FILE, ER(ER_LOG_PURGE_NO_FILE),
                                  log_info.log_file_name);
            }
            sql_print_information("Failed to delete file '%s'",
                                  log_info.log_file_name);
            my_errno= 0;
          }
          else
          {
            if (thd)
            {
              push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                                  ER_BINLOG_PURGE_FATAL_ERR,
                                  "a problem with deleting %s; "
                                  "consider examining correspondence "
                                  "of your binlog index file "
                                  "to the actual binlog files",
                                  log_info.log_file_name);
            }
            else
            {
              sql_print_information("Failed to delete file '%s'; "
                                    "consider examining correspondence "
                                    "of your binlog index file "
                                    "to the actual binlog files",
                                    log_info.log_file_name);
            }
            if (my_errno == EMFILE)
            {
              DBUG_PRINT("info",
                         ("my_errno: %d, set ret = LOG_INFO_EMFILE", my_errno));
              error= LOG_INFO_EMFILE;
              goto err;
            }
            error= LOG_INFO_FATAL;
            goto err;
          }
        }
      }
    }
  }

err:
  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::purge_logs_before_date(time_t purge_time, bool auto_purge)
{
  int error;
  int no_of_threads_locking_log= 0, no_of_log_files_purged= 0;
  bool log_is_active= false, log_is_in_use= false;
  char to_log[FN_REFLEN], copy_log_in_use[FN_REFLEN];
  LOG_INFO log_info;
  MY_STAT stat_area;
  THD *thd= current_thd;

  DBUG_ENTER("purge_logs_before_date");

  mysql_mutex_lock(&LOCK_index);
  to_log[0]= 0;

  if ((error=find_log_pos(&log_info, NullS, false/*need_lock_index=false*/)))
    goto err;

  while (!(log_is_active= is_active(log_info.log_file_name)))
  {
    if ((no_of_threads_locking_log= log_in_use(log_info.log_file_name)))
    {
      if (!auto_purge)
      {
        log_is_in_use= true;
        strcpy(copy_log_in_use, log_info.log_file_name);
      }
      break;
    }
    no_of_log_files_purged++;

    if (!mysql_file_stat(m_key_file_log,
                         log_info.log_file_name, &stat_area, MYF(0)))
    {
      if (my_errno == ENOENT)
      {
        /*
          It's not fatal if we can't stat a log file that does not exist.
        */
        my_errno= 0;
      }
      else
      {
        /*
          Other than ENOENT are fatal
        */
        if (thd)
        {
          push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                              ER_BINLOG_PURGE_FATAL_ERR,
                              "a problem with getting info on being purged %s; "
                              "consider examining correspondence "
                              "of your binlog index file "
                              "to the actual binlog files",
                              log_info.log_file_name);
        }
        else
        {
          sql_print_information("Failed to delete log file '%s'",
                                log_info.log_file_name);
        }
        error= LOG_INFO_FATAL;
        goto err;
      }
    }
    else
    {
      if (stat_area.st_mtime < purge_time) 
        strmake(to_log, 
                log_info.log_file_name, 
                sizeof(log_info.log_file_name) - 1);
      else
        break;
    }
    if (find_next_log(&log_info, false/*need_lock_index=false*/))
      break;
  }

  if (log_is_active)
  {
    if(!auto_purge)
      push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                          ER_WARN_PURGE_LOG_IS_ACTIVE,
                          ER(ER_WARN_PURGE_LOG_IS_ACTIVE),
                          log_info.log_file_name);

  }

  if (log_is_in_use)
  {
    int no_of_log_files_to_purge= no_of_log_files_purged+1;
    while (strcmp(log_file_name, log_info.log_file_name))
    {
      if (mysql_file_stat(m_key_file_log, log_info.log_file_name,
                          &stat_area, MYF(0)))
      {
        if (stat_area.st_mtime < purge_time)
          no_of_log_files_to_purge++;
        else
          break;
      }
      if (find_next_log(&log_info, false/*need_lock_index=false*/))
      {
        no_of_log_files_to_purge++;
        break;
      }
    }

    push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
                        ER_WARN_PURGE_LOG_IN_USE,
                        ER(ER_WARN_PURGE_LOG_IN_USE),
                        copy_log_in_use, no_of_threads_locking_log,
                        no_of_log_files_purged, no_of_log_files_to_purge);
  }

  error= (to_log[0] ? purge_logs(to_log, true,
                                 false/*need_lock_index=false*/,
                                 true/*need_update_threads=true*/,
                                 (ulonglong *) 0, auto_purge) : 0);

err:
  mysql_mutex_unlock(&LOCK_index);
  DBUG_RETURN(error);
}
#endif /* HAVE_REPLICATION */


void MYSQL_BIN_LOG::make_log_name(char* buf, const char* log_ident)
{
  uint dir_len = dirname_length(log_file_name); 
  if (dir_len >= FN_REFLEN)
    dir_len=FN_REFLEN-1;
  strnmov(buf, log_file_name, dir_len);
  strmake(buf+dir_len, log_ident, FN_REFLEN - dir_len -1);
}


bool MYSQL_BIN_LOG::is_active(const char *log_file_name_arg)
{
  return !strcmp(log_file_name, log_file_name_arg);
}


/*
  Wrappers around new_file_impl to avoid using argument
  to control locking. The argument 1) less readable 2) breaks
  incapsulation 3) allows external access to the class without
  a lock (which is not possible with private new_file_without_locking
  method).
  
  @retval
    nonzero - error

*/

int MYSQL_BIN_LOG::new_file(Format_description_log_event *extra_description_event)
{
  return new_file_impl(true/*need_lock_log=true*/, extra_description_event);
}

/*
  @retval
    nonzero - error
*/
int MYSQL_BIN_LOG::new_file_without_locking(Format_description_log_event *extra_description_event)
{
  return new_file_impl(false/*need_lock_log=false*/, extra_description_event);
}


int MYSQL_BIN_LOG::new_file_impl(bool need_lock_log, Format_description_log_event *extra_description_event)
{
  int error= 0, close_on_error= FALSE;
  char new_name[FN_REFLEN], *new_name_ptr, *old_name, *file_to_open;

  DBUG_ENTER("MYSQL_BIN_LOG::new_file_impl");
  if (!is_open())
  {
    DBUG_PRINT("info",("log is closed"));
    DBUG_RETURN(error);
  }

  if (need_lock_log)
    mysql_mutex_lock(&LOCK_log);
  else
    mysql_mutex_assert_owner(&LOCK_log);
  DBUG_EXECUTE_IF("semi_sync_3-way_deadlock",
                  DEBUG_SYNC(current_thd, "before_rotate_binlog"););
  mysql_mutex_lock(&LOCK_xids);
  /*
    We need to ensure that the number of prepared XIDs are 0.

    If m_prep_xids is not zero:
    - We wait for storage engine commit, hence decrease m_prep_xids
    - We keep the LOCK_log to block new transactions from being
      written to the binary log.
   */
  while (get_prep_xids() > 0)
    mysql_cond_wait(&m_prep_xids_cond, &LOCK_xids);
  mysql_mutex_unlock(&LOCK_xids);

  mysql_mutex_lock(&LOCK_index);

  if (DBUG_EVALUATE_IF("expire_logs_always", 0, 1)
      && (error= ha_flush_logs(NULL)))
    goto end;

  mysql_mutex_assert_owner(&LOCK_log);
  mysql_mutex_assert_owner(&LOCK_index);

  /* Reuse old name if not binlog and not update log */
  new_name_ptr= name;

  /*
    If user hasn't specified an extension, generate a new log name
    We have to do this here and not in open as we want to store the
    new file name in the current binary log file.
  */
  if ((error= generate_new_name(new_name, name)))
    goto end;
  else
  {
    new_name_ptr=new_name;
    /*
      We log the whole file name for log file as the user may decide
      to change base names at some point.
    */
    Rotate_log_event r(new_name+dirname_length(new_name), 0, LOG_EVENT_OFFSET,
                       is_relay_log ? Rotate_log_event::RELAY_LOG : 0);
    /* 
      The current relay-log's closing Rotate event must have checksum
      value computed with an algorithm of the last relay-logged FD event.
    */
    if (is_relay_log)
      r.checksum_alg= relay_log_checksum_alg;
    DBUG_ASSERT(!is_relay_log || relay_log_checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF);
    if(DBUG_EVALUATE_IF("fault_injection_new_file_rotate_event", (error=close_on_error=TRUE), FALSE) ||
       (error= r.write(&log_file)))
    {
      char errbuf[MYSYS_STRERROR_SIZE];
      DBUG_EXECUTE_IF("fault_injection_new_file_rotate_event", errno=2;);
      close_on_error= TRUE;
      my_printf_error(ER_ERROR_ON_WRITE, ER(ER_CANT_OPEN_FILE),
                      MYF(ME_FATALERROR), name,
                      errno, my_strerror(errbuf, sizeof(errbuf), errno));
      goto end;
    }
    bytes_written += r.data_written;
  }
  /*
    Update needs to be signalled even if there is no rotate event
    log rotation should give the waiting thread a signal to
    discover EOF and move on to the next log.
  */
  signal_update();

  old_name=name;
  name=0;                               // Don't free name
  close(LOG_CLOSE_TO_BE_OPENED | LOG_CLOSE_INDEX);

  if (checksum_alg_reset != BINLOG_CHECKSUM_ALG_UNDEF)
  {
    DBUG_ASSERT(!is_relay_log);
    DBUG_ASSERT(binlog_checksum_options != checksum_alg_reset);
    binlog_checksum_options= checksum_alg_reset;
  }
  /*
     Note that at this point, log_state != LOG_CLOSED (important for is_open()).
  */

  /*
     new_file() is only used for rotation (in FLUSH LOGS or because size >
     max_binlog_size or max_relay_log_size).
     If this is a binary log, the Format_description_log_event at the beginning of
     the new file should have created=0 (to distinguish with the
     Format_description_log_event written at server startup, which should
     trigger temp tables deletion on slaves.
  */

  /* reopen index binlog file, BUG#34582 */
  file_to_open= index_file_name;
  error= open_index_file(index_file_name, 0, false/*need_lock_index=false*/);
  if (!error)
  {
    /* reopen the binary log file. */
    file_to_open= new_name_ptr;
    error= open_binlog(old_name, new_name_ptr, io_cache_type,
                       max_size, true,
                       false/*need_lock_index=false*/,
                       true/*need_sid_lock=true*/,
                       extra_description_event);
  }

  /* handle reopening errors */
  if (error)
  {
    char errbuf[MYSYS_STRERROR_SIZE];
    my_printf_error(ER_CANT_OPEN_FILE, ER(ER_CANT_OPEN_FILE), 
                    MYF(ME_FATALERROR), file_to_open,
                    error, my_strerror(errbuf, sizeof(errbuf), error));
    close_on_error= TRUE;
  }
  my_free(old_name);

end:

  if (error && close_on_error /* rotate or reopen failed */)
  {
    /* 
      Close whatever was left opened.

      We are keeping the behavior as it exists today, ie,
      we disable logging and move on (see: BUG#51014).

      TODO: as part of WL#1790 consider other approaches:
       - kill mysql (safety);
       - try multiple locations for opening a log file;
       - switch server to protected/readonly mode
       - ...
    */
    close(LOG_CLOSE_INDEX);
    sql_print_error("Could not open %s for logging (error %d). "
                    "Turning logging off for the whole duration "
                    "of the MySQL server process. To turn it on "
                    "again: fix the cause, shutdown the MySQL "
                    "server and restart it.", 
                    new_name_ptr, errno);
  }

  mysql_mutex_unlock(&LOCK_index);
  if (need_lock_log)
    mysql_mutex_unlock(&LOCK_log);

  DBUG_RETURN(error);
}


#ifdef HAVE_REPLICATION

bool MYSQL_BIN_LOG::after_append_to_relay_log(Master_info *mi)
{
  DBUG_ENTER("MYSQL_BIN_LOG::after_append_to_relay_log");
  DBUG_PRINT("info",("max_size: %lu",max_size));

  // Check pre-conditions
  mysql_mutex_assert_owner(&LOCK_log);
  mysql_mutex_assert_owner(&mi->data_lock);
  DBUG_ASSERT(is_relay_log);
  DBUG_ASSERT(current_thd->system_thread == SYSTEM_THREAD_SLAVE_IO);

  // Flush and sync
  bool error= false;
  if (flush_and_sync(0) == 0)
  {
    // If relay log is too big, rotate
    if ((uint) my_b_append_tell(&log_file) >
        DBUG_EVALUATE_IF("rotate_slave_debug_group", 500, max_size))
    {
      error= new_file_without_locking(mi->get_mi_description_event());
    }
  }

  signal_update();

  DBUG_RETURN(error);
}


bool MYSQL_BIN_LOG::append_event(Log_event* ev, Master_info *mi)
{
  DBUG_ENTER("MYSQL_BIN_LOG::append");

  // check preconditions
  DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);
  DBUG_ASSERT(is_relay_log);

  // acquire locks
  mysql_mutex_lock(&LOCK_log);

  // write data
  bool error = false;
  if (ev->write(&log_file) == 0)
  {
    bytes_written+= ev->data_written;
    error= after_append_to_relay_log(mi);
  }
  else
    error= true;

  mysql_mutex_unlock(&LOCK_log);
  DBUG_RETURN(error);
}


bool MYSQL_BIN_LOG::append_buffer(const char* buf, uint len, Master_info *mi)
{
  DBUG_ENTER("MYSQL_BIN_LOG::append_buffer");

  // check preconditions
  DBUG_ASSERT(log_file.type == SEQ_READ_APPEND);
  DBUG_ASSERT(is_relay_log);
  mysql_mutex_assert_owner(&LOCK_log);

  // write data
  bool error= false;
  if (my_b_append(&log_file,(uchar*) buf,len) == 0)
  {
    bytes_written += len;
    error= after_append_to_relay_log(mi);
  }
  else
    error= true;

  DBUG_RETURN(error);
}
#endif // ifdef HAVE_REPLICATION

bool MYSQL_BIN_LOG::flush_and_sync(const bool force)
{
  mysql_mutex_assert_owner(&LOCK_log);

  if (flush_io_cache(&log_file))
    return 1;

  std::pair<bool, bool> result= sync_binlog_file(force);

  return result.first;
}

void MYSQL_BIN_LOG::start_union_events(THD *thd, query_id_t query_id_param)
{
  DBUG_ASSERT(!thd->binlog_evt_union.do_union);
  thd->binlog_evt_union.do_union= TRUE;
  thd->binlog_evt_union.unioned_events= FALSE;
  thd->binlog_evt_union.unioned_events_trans= FALSE;
  thd->binlog_evt_union.first_query_id= query_id_param;
}

void MYSQL_BIN_LOG::stop_union_events(THD *thd)
{
  DBUG_ASSERT(thd->binlog_evt_union.do_union);
  thd->binlog_evt_union.do_union= FALSE;
}

bool MYSQL_BIN_LOG::is_query_in_union(THD *thd, query_id_t query_id_param)
{
  return (thd->binlog_evt_union.do_union && 
          query_id_param >= thd->binlog_evt_union.first_query_id);
}

/*
  Updates thd's position-of-next-event variables
  after a *real* write a file.
 */
void MYSQL_BIN_LOG::update_thd_next_event_pos(THD* thd)
{
  if (likely(thd != NULL))
  {
    thd->set_next_event_pos(log_file_name,
                            my_b_tell(&log_file));
  }
}

/*
  Moves the last bunch of rows from the pending Rows event to a cache (either
  transactional cache if is_transaction is @c true, or the non-transactional
  cache otherwise. Sets a new pending event.

  @param thd               a pointer to the user thread.
  @param evt               a pointer to the row event.
  @param is_transactional  @c true indicates a transactional cache,
                           otherwise @c false a non-transactional.
*/
int
MYSQL_BIN_LOG::flush_and_set_pending_rows_event(THD *thd,
                                                Rows_log_event* event,
                                                bool is_transactional)
{
  DBUG_ENTER("MYSQL_BIN_LOG::flush_and_set_pending_rows_event(event)");
  DBUG_ASSERT(mysql_bin_log.is_open());
  DBUG_PRINT("enter", ("event: 0x%lx", (long) event));

  int error= 0;
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(thd);

  DBUG_ASSERT(cache_mngr);

  binlog_cache_data *cache_data=
    cache_mngr->get_binlog_cache_data(is_transactional);

  DBUG_PRINT("info", ("cache_mngr->pending(): 0x%lx", (long) cache_data->pending()));

  if (Rows_log_event* pending= cache_data->pending())
  {
    /*
      Write pending event to the cache.
    */
    if (cache_data->write_event(thd, pending))
    {
      set_write_error(thd, is_transactional);
      if (check_write_error(thd) && cache_data &&
          stmt_cannot_safely_rollback(thd))
        cache_data->set_incident();
      delete pending;
      cache_data->set_pending(NULL);
      DBUG_RETURN(1);
    }

    delete pending;
  }

  cache_data->set_pending(event);

  DBUG_RETURN(error);
}

bool MYSQL_BIN_LOG::write_event(Log_event *event_info)
{
  THD *thd= event_info->thd;
  bool error= 1;
  DBUG_ENTER("MYSQL_BIN_LOG::write_event(Log_event *)");

  if (thd->binlog_evt_union.do_union)
  {
    /*
      In Stored function; Remember that function call caused an update.
      We will log the function call to the binary log on function exit
    */
    thd->binlog_evt_union.unioned_events= TRUE;
    thd->binlog_evt_union.unioned_events_trans |=
      event_info->is_using_trans_cache();
    DBUG_RETURN(0);
  }

  /*
    We only end the statement if we are in a top-level statement.  If
    we are inside a stored function, we do not end the statement since
    this will close all tables on the slave.
  */
  bool const end_stmt=
    thd->locked_tables_mode && thd->lex->requires_prelocking();
  if (thd->binlog_flush_pending_rows_event(end_stmt,
                                           event_info->is_using_trans_cache()))
    DBUG_RETURN(error);

  /*
     In most cases this is only called if 'is_open()' is true; in fact this is
     mostly called if is_open() *was* true a few instructions before, but it
     could have changed since.
  */
  if (likely(is_open()))
  {
#ifdef HAVE_REPLICATION
    /*
      In the future we need to add to the following if tests like
      "do the involved tables match (to be implemented)
      binlog_[wild_]{do|ignore}_table?" (WL#1049)"
    */
    const char *local_db= event_info->get_db();
    if ((thd && !(thd->variables.option_bits & OPTION_BIN_LOG)) ||
        (thd->lex->sql_command != SQLCOM_ROLLBACK_TO_SAVEPOINT &&
         thd->lex->sql_command != SQLCOM_SAVEPOINT &&
         (!event_info->is_no_filter_event() && 
          !binlog_filter->db_ok(local_db))))
      DBUG_RETURN(0);
#endif /* HAVE_REPLICATION */

    DBUG_ASSERT(event_info->is_using_trans_cache() || event_info->is_using_stmt_cache());
    
    if (binlog_start_trans_and_stmt(thd, event_info))
      DBUG_RETURN(error);

    bool is_trans_cache= event_info->is_using_trans_cache();
    binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
    binlog_cache_data *cache_data= cache_mngr->get_binlog_cache_data(is_trans_cache);
    
    DBUG_PRINT("info",("event type: %d",event_info->get_type_code()));

    /*
       No check for auto events flag here - this write method should
       never be called if auto-events are enabled.

       Write first log events which describe the 'run environment'
       of the SQL command. If row-based binlogging, Insert_id, Rand
       and other kind of "setting context" events are not needed.
    */
    if (thd)
    {
      if (!thd->is_current_stmt_binlog_format_row())
      {
        if (thd->stmt_depends_on_first_successful_insert_id_in_prev_stmt)
        {
          Intvar_log_event e(thd,(uchar) LAST_INSERT_ID_EVENT,
                             thd->first_successful_insert_id_in_prev_stmt_for_binlog,
                             event_info->event_cache_type, event_info->event_logging_type);
          if (cache_data->write_event(thd, &e))
            goto err;
        }
        if (thd->auto_inc_intervals_in_cur_stmt_for_binlog.nb_elements() > 0)
        {
          DBUG_PRINT("info",("number of auto_inc intervals: %u",
                             thd->auto_inc_intervals_in_cur_stmt_for_binlog.
                             nb_elements()));
          Intvar_log_event e(thd, (uchar) INSERT_ID_EVENT,
                             thd->auto_inc_intervals_in_cur_stmt_for_binlog.
                             minimum(), event_info->event_cache_type,
                             event_info->event_logging_type);
          if (cache_data->write_event(thd, &e))
            goto err;
        }
        if (thd->rand_used)
        {
          Rand_log_event e(thd,thd->rand_saved_seed1,thd->rand_saved_seed2,
                           event_info->event_cache_type,
                           event_info->event_logging_type);
          if (cache_data->write_event(thd, &e))
            goto err;
        }
        if (thd->user_var_events.elements)
        {
          for (uint i= 0; i < thd->user_var_events.elements; i++)
          {
            BINLOG_USER_VAR_EVENT *user_var_event;
            get_dynamic(&thd->user_var_events,(uchar*) &user_var_event, i);

            /* setting flags for user var log event */
            uchar flags= User_var_log_event::UNDEF_F;
            if (user_var_event->unsigned_flag)
              flags|= User_var_log_event::UNSIGNED_F;

            User_var_log_event e(thd,
                                 user_var_event->user_var_event->entry_name.ptr(),
                                 user_var_event->user_var_event->entry_name.length(),
                                 user_var_event->value,
                                 user_var_event->length,
                                 user_var_event->type,
                                 user_var_event->charset_number, flags,
                                 event_info->event_cache_type,
                                 event_info->event_logging_type);
            if (cache_data->write_event(thd, &e))
              goto err;
          }
        }
      }
    }

    /*
      Write the event.
    */
    if (cache_data->write_event(thd, event_info) ||
        DBUG_EVALUATE_IF("injecting_fault_writing", 1, 0))
      goto err;

    /*
      After writing the event, if the trx-cache was used and any unsafe
      change was written into it, the cache is marked as cannot safely
      roll back.
    */
    if (is_trans_cache && stmt_cannot_safely_rollback(thd))
      cache_mngr->trx_cache.set_cannot_rollback();

    error= 0;

err:
    if (error)
    {
      set_write_error(thd, is_trans_cache);
      if (check_write_error(thd) && cache_data &&
          stmt_cannot_safely_rollback(thd))
        cache_data->set_incident();
    }
  }

  DBUG_RETURN(error);
}

int MYSQL_BIN_LOG::rotate(bool force_rotate, bool* check_purge)
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::rotate");

  DBUG_ASSERT(!is_relay_log);
  mysql_mutex_assert_owner(&LOCK_log);

  *check_purge= false;

  if (force_rotate || (my_b_tell(&log_file) >= (my_off_t) max_size))
  {
    if ((error= new_file_without_locking(NULL)))
      if (!write_incident(current_thd, false/*need_lock_log=false*/,
                          false/*do_flush_and_sync==false*/))
      {
        /*
          Write an error to log. So that user might have a chance
          to be alerted and explore incident details before its
          slave servers would stop.
        */
        sql_print_error("The server was unable to create a new log file. "
                        "An incident event has been written to the binary "
                        "log which will stop the slaves.");
        flush_and_sync(0);
      }

    *check_purge= true;
  }
  DBUG_RETURN(error);
}

void MYSQL_BIN_LOG::purge()
{
#ifdef HAVE_REPLICATION
  if (expire_logs_days)
  {
    DEBUG_SYNC(current_thd, "at_purge_logs_before_date");
    time_t purge_time= my_time(0) - expire_logs_days*24*60*60;
    DBUG_EXECUTE_IF("expire_logs_always",
                    { purge_time= my_time(0);});
    if (purge_time >= 0)
    {
      /*
        Flush logs for storage engines, so that the last transaction
        is fsynced inside storage engines.
      */
      ha_flush_logs(NULL);
      purge_logs_before_date(purge_time, true);
    }
  }
#endif
}

int MYSQL_BIN_LOG::rotate_and_purge(bool force_rotate)
{
  int error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::rotate_and_purge");
  bool check_purge= false;

  DBUG_ASSERT(!is_relay_log);
  mysql_mutex_lock(&LOCK_log);
  error= rotate(force_rotate, &check_purge);
  /*
    NOTE: Run purge_logs wo/ holding LOCK_log because it does not need
          the mutex. Otherwise causes various deadlocks.
  */
  mysql_mutex_unlock(&LOCK_log);

  if (!error && check_purge)
    purge();

  DBUG_RETURN(error);
}

uint MYSQL_BIN_LOG::next_file_id()
{
  uint res;
  mysql_mutex_lock(&LOCK_log);
  res = file_id++;
  mysql_mutex_unlock(&LOCK_log);
  return res;
}


  static ulong fix_log_event_crc(uchar *buf, uint off, uint event_len,
                                 uint length, ha_checksum *crc)
{
  ulong ret;
  uchar *event_begin= buf + off;
  uint16 flags= uint2korr(event_begin + FLAGS_OFFSET);

  DBUG_ASSERT(length >= off + LOG_EVENT_HEADER_LEN); //at least common header in
  int2store(event_begin + FLAGS_OFFSET, flags);
  ret= length >= off + event_len ? 0 : off + event_len - length;
  *crc= my_checksum(*crc, event_begin, event_len - ret); 
  return ret;
}

/*
  Write the contents of a cache to the binary log.

  SYNOPSIS
    do_write_cache()
    cache    Cache to write to the binary log
    lock_log True if the LOCK_log mutex should be aquired, false otherwise

  DESCRIPTION
    Write the contents of the cache to the binary log. The cache will
    be reset as a READ_CACHE to be able to read the contents from it.

    Reading from the trans cache with possible (per @c binlog_checksum_options) 
    adding checksum value  and then fixing the length and the end_log_pos of 
    events prior to fill in the binlog cache.
*/

int MYSQL_BIN_LOG::do_write_cache(IO_CACHE *cache)
{
  DBUG_ENTER("MYSQL_BIN_LOG::do_write_cache(IO_CACHE *)");

  DBUG_EXECUTE_IF("simulate_do_write_cache_failure",
                  {
                    /* 
                       see binlog_cache_data::write_event() that reacts on
                       @c simulate_disk_full_at_flush_pending.
                    */
                    DBUG_SET("-d,simulate_do_write_cache_failure");
                    DBUG_RETURN(ER_ERROR_ON_WRITE);
                  });

  if (reinit_io_cache(cache, READ_CACHE, 0, 0, 0))
    DBUG_RETURN(ER_ERROR_ON_WRITE);
  uint length= my_b_bytes_in_cache(cache), group, carry, hdr_offs;
  ulong remains= 0; // part of unprocessed yet netto length of the event
  long val;
  ulong end_log_pos_inc= 0; // each event processed adds BINLOG_CHECKSUM_LEN 2 t
  uchar header[LOG_EVENT_HEADER_LEN];
  ha_checksum crc= 0, crc_0= 0; // assignments to keep compiler happy
  my_bool do_checksum= (binlog_checksum_options != BINLOG_CHECKSUM_ALG_OFF);
  uchar buf[BINLOG_CHECKSUM_LEN];

  // while there is just one alg the following must hold:
  DBUG_ASSERT(!do_checksum ||
              binlog_checksum_options == BINLOG_CHECKSUM_ALG_CRC32);

  /*
    The events in the buffer have incorrect end_log_pos data
    (relative to beginning of group rather than absolute),
    so we'll recalculate them in situ so the binlog is always
    correct, even in the middle of a group. This is possible
    because we now know the start position of the group (the
    offset of this cache in the log, if you will); all we need
    to do is to find all event-headers, and add the position of
    the group to the end_log_pos of each event.  This is pretty
    straight forward, except that we read the cache in segments,
    so an event-header might end up on the cache-border and get
    split.
  */

  group= (uint)my_b_tell(&log_file);
  DBUG_PRINT("debug", ("length: %llu, group: %llu",
                       (ulonglong) length, (ulonglong) group));
  hdr_offs= carry= 0;
  if (do_checksum)
    crc= crc_0= my_checksum(0L, NULL, 0);

  if (DBUG_EVALUATE_IF("fault_injection_crc_value", 1, 0))
    crc= crc - 1;

  do
  {
    /*
      if we only got a partial header in the last iteration,
      get the other half now and process a full header.
    */
    if (unlikely(carry > 0))
    {
      DBUG_ASSERT(carry < LOG_EVENT_HEADER_LEN);

      /* assemble both halves */
      memcpy(&header[carry], (char *)cache->read_pos,
             LOG_EVENT_HEADER_LEN - carry);

      /* fix end_log_pos */
      val=uint4korr(header + LOG_POS_OFFSET);
      val+= group +
        (end_log_pos_inc+= (do_checksum ? BINLOG_CHECKSUM_LEN : 0));
      int4store(&header[LOG_POS_OFFSET], val);

      if (do_checksum)
      {
        ulong len= uint4korr(header + EVENT_LEN_OFFSET);
        /* fix len */
        int4store(&header[EVENT_LEN_OFFSET], len + BINLOG_CHECKSUM_LEN);
      }

      /* write the first half of the split header */
      if (my_b_write(&log_file, header, carry))
        DBUG_RETURN(ER_ERROR_ON_WRITE);

      /*
        copy fixed second half of header to cache so the correct
        version will be written later.
      */
      memcpy((char *)cache->read_pos, &header[carry],
             LOG_EVENT_HEADER_LEN - carry);

      /* next event header at ... */
      hdr_offs= uint4korr(header + EVENT_LEN_OFFSET) - carry -
        (do_checksum ? BINLOG_CHECKSUM_LEN : 0);

      if (do_checksum)
      {
        DBUG_ASSERT(crc == crc_0 && remains == 0);
        crc= my_checksum(crc, header, carry);
        remains= uint4korr(header + EVENT_LEN_OFFSET) - carry -
          BINLOG_CHECKSUM_LEN;
      }
      carry= 0;
    }

    /* if there is anything to write, process it. */

    if (likely(length > 0))
    {
      /*
        process all event-headers in this (partial) cache.
        if next header is beyond current read-buffer,
        we'll get it later (though not necessarily in the
        very next iteration, just "eventually").
      */

      /* crc-calc the whole buffer */
      if (do_checksum && hdr_offs >= length)
      {

        DBUG_ASSERT(remains != 0 && crc != crc_0);

        crc= my_checksum(crc, cache->read_pos, length); 
        remains -= length;
        if (my_b_write(&log_file, cache->read_pos, length))
          DBUG_RETURN(ER_ERROR_ON_WRITE);
        if (remains == 0)
        {
          int4store(buf, crc);
          if (my_b_write(&log_file, buf, BINLOG_CHECKSUM_LEN))
            DBUG_RETURN(ER_ERROR_ON_WRITE);
          crc= crc_0;
        }
      }

      while (hdr_offs < length)
      {
        /*
          partial header only? save what we can get, process once
          we get the rest.
        */

        if (do_checksum)
        {
          if (remains != 0)
          {
            /*
              finish off with remains of the last event that crawls
              from previous into the current buffer
            */
            DBUG_ASSERT(crc != crc_0);
            crc= my_checksum(crc, cache->read_pos, hdr_offs);
            int4store(buf, crc);
            remains -= hdr_offs;
            DBUG_ASSERT(remains == 0);
            if (my_b_write(&log_file, cache->read_pos, hdr_offs) ||
                my_b_write(&log_file, buf, BINLOG_CHECKSUM_LEN))
              DBUG_RETURN(ER_ERROR_ON_WRITE);
            crc= crc_0;
          }
        }

        if (hdr_offs + LOG_EVENT_HEADER_LEN > length)
        {
          carry= length - hdr_offs;
          memcpy(header, (char *)cache->read_pos + hdr_offs, carry);
          length= hdr_offs;
        }
        else
        {
          /* we've got a full event-header, and it came in one piece */
          uchar *ev= (uchar *)cache->read_pos + hdr_offs;
          uint event_len= uint4korr(ev + EVENT_LEN_OFFSET); // netto len
          uchar *log_pos= ev + LOG_POS_OFFSET;

          /* fix end_log_pos */
          val= uint4korr(log_pos) + group +
            (end_log_pos_inc += (do_checksum ? BINLOG_CHECKSUM_LEN : 0));
          int4store(log_pos, val);

          /* fix CRC */
          if (do_checksum)
          {
            /* fix length */
            int4store(ev + EVENT_LEN_OFFSET, event_len + BINLOG_CHECKSUM_LEN);
            remains= fix_log_event_crc(cache->read_pos, hdr_offs, event_len,
                                       length, &crc);
            if (my_b_write(&log_file, ev, 
                           remains == 0 ? event_len : length - hdr_offs))
              DBUG_RETURN(ER_ERROR_ON_WRITE);
            if (remains == 0)
            {
              int4store(buf, crc);
              if (my_b_write(&log_file, buf, BINLOG_CHECKSUM_LEN))
                DBUG_RETURN(ER_ERROR_ON_WRITE);
              crc= crc_0; // crc is complete
            }
          }

          /* next event header at ... */
          hdr_offs += event_len; // incr by the netto len

          DBUG_ASSERT(!do_checksum || remains == 0 || hdr_offs >= length);
        }
      }

      /*
        Adjust hdr_offs. Note that it may still point beyond the segment
        read in the next iteration; if the current event is very long,
        it may take a couple of read-iterations (and subsequent adjustments
        of hdr_offs) for it to point into the then-current segment.
        If we have a split header (!carry), hdr_offs will be set at the
        beginning of the next iteration, overwriting the value we set here:
      */
      hdr_offs -= length;
    }

    /* Write the entire buf to the binary log file */
    if (!do_checksum)
      if (my_b_write(&log_file, cache->read_pos, length))
        DBUG_RETURN(ER_ERROR_ON_WRITE);
    cache->read_pos=cache->read_end;            // Mark buffer used up
  } while ((length= my_b_fill(cache)));

  DBUG_ASSERT(carry == 0);
  DBUG_ASSERT(!do_checksum || remains == 0);
  DBUG_ASSERT(!do_checksum || crc == crc_0);

  DBUG_RETURN(0); // All OK
}

bool MYSQL_BIN_LOG::write_incident(Incident_log_event *ev, bool need_lock_log,
                                   bool do_flush_and_sync)
{
  uint error= 0;
  DBUG_ENTER("MYSQL_BIN_LOG::write_incident");

  if (!is_open())
    DBUG_RETURN(error);

  if (need_lock_log)
    mysql_mutex_lock(&LOCK_log);
  else
    mysql_mutex_assert_owner(&LOCK_log);

  // @todo make this work with the group log. /sven

  error= ev->write(&log_file);

  if (do_flush_and_sync)
  {
    if (!error && !(error= flush_and_sync()))
    {
      bool check_purge= false;
      signal_update();
      error= rotate(true, &check_purge);
      if (!error && check_purge)
        purge();
    }
  }

  if (need_lock_log)
    mysql_mutex_unlock(&LOCK_log);

  DBUG_RETURN(error);
}
bool MYSQL_BIN_LOG::write_incident(THD *thd, bool need_lock_log,
                                   bool do_flush_and_sync)
{
  DBUG_ENTER("MYSQL_BIN_LOG::write_incident");

  if (!is_open())
    DBUG_RETURN(0);

  LEX_STRING const write_error_msg=
    { C_STRING_WITH_LEN("error writing to the binary log") };
  Incident incident= INCIDENT_LOST_EVENTS;
  Incident_log_event ev(thd, incident, write_error_msg);

  DBUG_RETURN(write_incident(&ev, need_lock_log, do_flush_and_sync));
}

bool MYSQL_BIN_LOG::write_cache(THD *thd, binlog_cache_data *cache_data)
{
  DBUG_ENTER("MYSQL_BIN_LOG::write_cache(THD *, binlog_cache_data *, bool)");

  IO_CACHE *cache= &cache_data->cache_log;
  bool incident= cache_data->has_incident();

  DBUG_EXECUTE_IF("simulate_binlog_flush_error",
                  {
                    if (rand() % 3 == 0)
                    {
                      write_error=1;
                      goto err;
                    }
                  };);

  mysql_mutex_assert_owner(&LOCK_log);

  DBUG_ASSERT(is_open());
  if (likely(is_open()))                       // Should always be true
  {
    /*
      We only bother to write to the binary log if there is anything
      to write.
     */
    if (my_b_tell(cache) > 0)
    {
      DBUG_EXECUTE_IF("crash_before_writing_xid",
                      {
                        if ((write_error= do_write_cache(cache)))
                          DBUG_PRINT("info", ("error writing binlog cache: %d",
                                               write_error));
                        flush_and_sync(true);
                        DBUG_PRINT("info", ("crashing before writing xid"));
                        DBUG_SUICIDE();
                      });

      if ((write_error= do_write_cache(cache)))
        goto err;

      if (incident && write_incident(thd, false/*need_lock_log=false*/,
                                     false/*do_flush_and_sync==false*/))
        goto err;

      DBUG_EXECUTE_IF("half_binlogged_transaction", DBUG_SUICIDE(););
      if (cache->error)                         // Error on read
      {
        char errbuf[MYSYS_STRERROR_SIZE];
        sql_print_error(ER(ER_ERROR_ON_READ), cache->file_name,
                        errno, my_strerror(errbuf, sizeof(errbuf), errno));
        write_error=1;                          // Don't give more errors
        goto err;
      }

      global_sid_lock->rdlock();
      if (gtid_state->update_on_flush(thd) != RETURN_STATUS_OK)
      {
        global_sid_lock->unlock();
        goto err;
      }
      global_sid_lock->unlock();
    }
    update_thd_next_event_pos(thd);
  }

  DBUG_RETURN(0);

err:
  if (!write_error)
  {
    char errbuf[MYSYS_STRERROR_SIZE];
    write_error= 1;
    sql_print_error(ER(ER_ERROR_ON_WRITE), name,
                    errno, my_strerror(errbuf, sizeof(errbuf), errno));
  }
  thd->commit_error= THD::CE_FLUSH_ERROR;

  DBUG_RETURN(1);
}


int MYSQL_BIN_LOG::wait_for_update_relay_log(THD* thd, const struct timespec *timeout)
{
  int ret= 0;
  PSI_stage_info old_stage;
  DBUG_ENTER("wait_for_update_relay_log");

  thd->ENTER_COND(&update_cond, &LOCK_log,
                  &stage_slave_has_read_all_relay_log,
                  &old_stage);

  if (!timeout)
    mysql_cond_wait(&update_cond, &LOCK_log);
  else
    ret= mysql_cond_timedwait(&update_cond, &LOCK_log,
                              const_cast<struct timespec *>(timeout));
  thd->EXIT_COND(&old_stage);

  DBUG_RETURN(ret);
}

int MYSQL_BIN_LOG::wait_for_update_bin_log(THD* thd,
                                           const struct timespec *timeout)
{
  int ret= 0;
  DBUG_ENTER("wait_for_update_bin_log");

  if (!timeout)
    mysql_cond_wait(&update_cond, &LOCK_log);
  else
    ret= mysql_cond_timedwait(&update_cond, &LOCK_log,
                              const_cast<struct timespec *>(timeout));
  DBUG_RETURN(ret);
}


void MYSQL_BIN_LOG::close(uint exiting)
{                                       // One can't set log_type here!
  DBUG_ENTER("MYSQL_BIN_LOG::close");
  DBUG_PRINT("enter",("exiting: %d", (int) exiting));
  if (log_state == LOG_OPENED)
  {
#ifdef HAVE_REPLICATION
    if ((exiting & LOG_CLOSE_STOP_EVENT) != 0)
    {
      Stop_log_event s;
      // the checksumming rule for relay-log case is similar to Rotate
        s.checksum_alg= is_relay_log ?
          relay_log_checksum_alg : binlog_checksum_options;
      DBUG_ASSERT(!is_relay_log ||
                  relay_log_checksum_alg != BINLOG_CHECKSUM_ALG_UNDEF);
      s.write(&log_file);
      bytes_written+= s.data_written;
      signal_update();
    }
#endif /* HAVE_REPLICATION */

    /* don't pwrite in a file opened with O_APPEND - it doesn't work */
    if (log_file.type == WRITE_CACHE)
    {
      my_off_t offset= BIN_LOG_HEADER_SIZE + FLAGS_OFFSET;
      my_off_t org_position= mysql_file_tell(log_file.file, MYF(0));
      uchar flags= 0;            // clearing LOG_EVENT_BINLOG_IN_USE_F
      mysql_file_pwrite(log_file.file, &flags, 1, offset, MYF(0));
      /*
        Restore position so that anything we have in the IO_cache is written
        to the correct position.
        We need the seek here, as mysql_file_pwrite() is not guaranteed to keep the
        original position on system that doesn't support pwrite().
      */
      mysql_file_seek(log_file.file, org_position, MY_SEEK_SET, MYF(0));
    }

    /* this will cleanup IO_CACHE, sync and close the file */
    MYSQL_LOG::close(exiting);
  }

  /*
    The following test is needed even if is_open() is not set, as we may have
    called a not complete close earlier and the index file is still open.
  */

  if ((exiting & LOG_CLOSE_INDEX) && my_b_inited(&index_file))
  {
    end_io_cache(&index_file);
    if (mysql_file_close(index_file.file, MYF(0)) < 0 && ! write_error)
    {
      char errbuf[MYSYS_STRERROR_SIZE];
      write_error= 1;
      sql_print_error(ER(ER_ERROR_ON_WRITE), index_file_name,
                      errno, my_strerror(errbuf, sizeof(errbuf), errno));
    }
  }
  log_state= (exiting & LOG_CLOSE_TO_BE_OPENED) ? LOG_TO_BE_OPENED : LOG_CLOSED;
  my_free(name);
  name= NULL;
  DBUG_VOID_RETURN;
}


void MYSQL_BIN_LOG::set_max_size(ulong max_size_arg)
{
  /*
    We need to take locks, otherwise this may happen:
    new_file() is called, calls open(old_max_size), then before open() starts,
    set_max_size() sets max_size to max_size_arg, then open() starts and
    uses the old_max_size argument, so max_size_arg has been overwritten and
    it's like if the SET command was never run.
  */
  DBUG_ENTER("MYSQL_BIN_LOG::set_max_size");
  mysql_mutex_lock(&LOCK_log);
  if (is_open())
    max_size= max_size_arg;
  mysql_mutex_unlock(&LOCK_log);
  DBUG_VOID_RETURN;
}


void MYSQL_BIN_LOG::signal_update()
{
  DBUG_ENTER("MYSQL_BIN_LOG::signal_update");
  signal_cnt++;
  mysql_cond_broadcast(&update_cond);
  DBUG_VOID_RETURN;
}

/****** transaction coordinator log for 2pc - binlog() based solution ******/

int MYSQL_BIN_LOG::open_binlog(const char *opt_name)
{
  LOG_INFO log_info;
  int      error= 1;

  /*
    This function is used for 2pc transaction coordination.  Hence, it
    is never used for relay logs.
  */
  DBUG_ASSERT(!is_relay_log);
  DBUG_ASSERT(total_ha_2pc > 1 || (1 == total_ha_2pc && opt_bin_log));
  DBUG_ASSERT(opt_name && opt_name[0]);

  if (!my_b_inited(&index_file))
  {
    /* There was a failure to open the index file, can't open the binlog */
    cleanup();
    return 1;
  }

  if (using_heuristic_recover())
  {
    /* generate a new binlog to mask a corrupted one */
    open_binlog(opt_name, 0, WRITE_CACHE, max_binlog_size, false,
                true/*need_lock_index=true*/,
                true/*need_sid_lock=true*/,
                NULL);
    cleanup();
    return 1;
  }

  if ((error= find_log_pos(&log_info, NullS, true/*need_lock_index=true*/)))
  {
    if (error != LOG_INFO_EOF)
      sql_print_error("find_log_pos() failed (error: %d)", error);
    else
      error= 0;
    goto err;
  }

  {
    const char *errmsg;
    IO_CACHE    log;
    File        file;
    Log_event  *ev=0;
    Format_description_log_event fdle(BINLOG_VERSION);
    char        log_name[FN_REFLEN];
    my_off_t    valid_pos= 0;
    my_off_t    binlog_size;
    MY_STAT     s;

    if (! fdle.is_valid())
      goto err;

    do
    {
      strmake(log_name, log_info.log_file_name, sizeof(log_name)-1);
    } while (!(error= find_next_log(&log_info, true/*need_lock_index=true*/)));

    if (error !=  LOG_INFO_EOF)
    {
      sql_print_error("find_log_pos() failed (error: %d)", error);
      goto err;
    }

    if ((file= open_binlog_file(&log, log_name, &errmsg)) < 0)
    {
      sql_print_error("%s", errmsg);
      goto err;
    }

    my_stat(log_name, &s, MYF(0));
    binlog_size= s.st_size;

    if ((ev= Log_event::read_log_event(&log, 0, &fdle,
                                       opt_master_verify_checksum)) &&
        ev->get_type_code() == FORMAT_DESCRIPTION_EVENT &&
        ev->flags & LOG_EVENT_BINLOG_IN_USE_F)
    {
      sql_print_information("Recovering after a crash using %s", opt_name);
      valid_pos= my_b_tell(&log);
      error= recover(&log, (Format_description_log_event *)ev, &valid_pos);
    }
    else
      error=0;

    delete ev;
    end_io_cache(&log);
    mysql_file_close(file, MYF(MY_WME));

    if (error)
      goto err;

    /* Trim the crashed binlog file to last valid transaction
      or event (non-transaction) base on valid_pos. */
    if (valid_pos > 0)
    {
      if ((file= mysql_file_open(key_file_binlog, log_name,
                                 O_RDWR | O_BINARY, MYF(MY_WME))) < 0)
      {
        sql_print_error("Failed to open the crashed binlog file "
                        "when master server is recovering it.");
        return -1;
      }

      /* Change binlog file size to valid_pos */
      if (valid_pos < binlog_size)
      {
        if (my_chsize(file, valid_pos, 0, MYF(MY_WME)))
        {
          sql_print_error("Failed to trim the crashed binlog file "
                          "when master server is recovering it.");
          mysql_file_close(file, MYF(MY_WME));
          return -1;
        }
        else
        {
          sql_print_information("Crashed binlog file %s size is %llu, "
                                "but recovered up to %llu. Binlog trimmed to %llu bytes.",
                                log_name, binlog_size, valid_pos, valid_pos);
        }
      }

      /* Clear LOG_EVENT_BINLOG_IN_USE_F */
      my_off_t offset= BIN_LOG_HEADER_SIZE + FLAGS_OFFSET;
      uchar flags= 0;
      if (mysql_file_pwrite(file, &flags, 1, offset, MYF(0)) != 1)
      {
        sql_print_error("Failed to clear LOG_EVENT_BINLOG_IN_USE_F "
                        "for the crashed binlog file when master "
                        "server is recovering it.");
        mysql_file_close(file, MYF(MY_WME));
        return -1;
      }

      mysql_file_close(file, MYF(MY_WME));
    } //end if
  }

err:
  return error;
}

void MYSQL_BIN_LOG::close()
{
}

/*
  Prepare the transaction in the transaction coordinator.

  This function will prepare the transaction in the storage engines
  (by calling @c ha_prepare_low) what will write a prepare record
  to the log buffers.

  @retval 0    success
  @retval 1    error
*/
int MYSQL_BIN_LOG::prepare(THD *thd, bool all)
{
  DBUG_ENTER("MYSQL_BIN_LOG::prepare");

  int error= ha_prepare_low(thd, all);

  DBUG_RETURN(error);
}

TC_LOG::enum_result MYSQL_BIN_LOG::commit(THD *thd, bool all)
{
  DBUG_ENTER("MYSQL_BIN_LOG::commit");

  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
  my_xid xid= thd->transaction.xid_state.xid.get_my_xid();
  int error= RESULT_SUCCESS;
  bool stuff_logged= false;

  DBUG_PRINT("enter", ("thd: 0x%llx, all: %s, xid: %llu, cache_mngr: 0x%llx",
                       (ulonglong) thd, YESNO(all), (ulonglong) xid,
                       (ulonglong) cache_mngr));

  /*
    No cache manager means nothing to log, but we still have to commit
    the transaction.
   */
  if (cache_mngr == NULL)
  {
    if (ha_commit_low(thd, all))
      DBUG_RETURN(RESULT_ABORTED);
    DBUG_RETURN(RESULT_SUCCESS);
  }

  THD_TRANS *trans= all ? &thd->transaction.all : &thd->transaction.stmt;

  DBUG_PRINT("debug", ("in_transaction: %s, no_2pc: %s, rw_ha_count: %d",
                       YESNO(thd->in_multi_stmt_transaction_mode()),
                       YESNO(trans->no_2pc),
                       trans->rw_ha_count));
  DBUG_PRINT("debug",
             ("all.cannot_safely_rollback(): %s, trx_cache_empty: %s",
              YESNO(thd->transaction.all.cannot_safely_rollback()),
              YESNO(cache_mngr->trx_cache.is_binlog_empty())));
  DBUG_PRINT("debug",
             ("stmt.cannot_safely_rollback(): %s, stmt_cache_empty: %s",
              YESNO(thd->transaction.stmt.cannot_safely_rollback()),
              YESNO(cache_mngr->stmt_cache.is_binlog_empty())));


  /*
    If there are no handlertons registered, there is nothing to
    commit. Note that DDLs are written earlier in this case (inside
    binlog_query).

    TODO: This can be a problem in those cases that there are no
    handlertons registered. DDLs are one example, but the other case
    is MyISAM. In this case, we could register a dummy handlerton to
    trigger the commit.

    Any statement that requires logging will call binlog_query before
    trans_commit_stmt, so an alternative is to use the condition
    "binlog_query called or stmt.ha_list != 0".
   */
  if (!all && trans->ha_list == 0 &&
      cache_mngr->stmt_cache.is_binlog_empty())
    DBUG_RETURN(RESULT_SUCCESS);

  /*
    If there is anything in the stmt cache, and GTIDs are enabled,
    then this is a single statement outside a transaction and it is
    impossible that there is anything in the trx cache.  Hence, we
    write any empty group(s) to the stmt cache.

    Otherwise, we write any empty group(s) to the trx cache at the end
    of the transaction.
  */
  if (!cache_mngr->stmt_cache.is_binlog_empty())
  {
    error= write_empty_groups_to_cache(thd, &cache_mngr->stmt_cache);
    if (error == 0)
    {
      if (cache_mngr->stmt_cache.finalize(thd))
        DBUG_RETURN(RESULT_ABORTED);
      stuff_logged= true;
    }
  }

  /*
    We commit the transaction if:
     - We are not in a transaction and committing a statement, or
     - We are in a transaction and a full transaction is committed.
    Otherwise, we accumulate the changes.
  */
  if (!error && !cache_mngr->trx_cache.is_binlog_empty() &&
      ending_trans(thd, all))
  {
    const bool real_trans= (all || thd->transaction.all.ha_list == 0);
    /*
      We are committing an XA transaction if it is a "real" transaction
      and have an XID assigned (because some handlerton registered). A
      transaction is "real" if either 'all' is true or the 'all.ha_list'
      is empty.

      Note: This is kind of strange since registering the binlog
      handlerton will then make the transaction XA, which is not really
      true. This occurs for example if a MyISAM statement is executed
      with row-based replication on.
   */
    if (real_trans && xid && trans->rw_ha_count > 1 && !trans->no_2pc)
    {
      Xid_log_event end_evt(thd, xid);
      if (cache_mngr->trx_cache.finalize(thd, &end_evt))
        DBUG_RETURN(RESULT_ABORTED);
    }
    else
    {
      Query_log_event end_evt(thd, STRING_WITH_LEN("COMMIT"),
                              true, FALSE, TRUE, 0, TRUE);
      if (cache_mngr->trx_cache.finalize(thd, &end_evt))
        DBUG_RETURN(RESULT_ABORTED);
    }
    stuff_logged= true;
  }

  /*
    This is part of the stmt rollback.
  */
  if (!all)
    cache_mngr->trx_cache.set_prev_position(MY_OFF_T_UNDEF);

  DBUG_PRINT("debug", ("error: %d", error));

  if (error)
    DBUG_RETURN(RESULT_ABORTED);

  /*
    Now all the events are written to the caches, so we will commit
    the transaction in the engines. This is done using the group
    commit logic in ordered_commit, which will return when the
    transaction is committed.

    If the commit in the engines fail, we still have something logged
    to the binary log so we have to report this as a "bad" failure
    (failed to commit, but logged something).
  */
  if (stuff_logged)
  {
    if (ordered_commit(thd, all))
      DBUG_RETURN(RESULT_INCONSISTENT);
  }
  else
  {
    if (ha_commit_low(thd, all))
      DBUG_RETURN(RESULT_INCONSISTENT);
  }

  DBUG_RETURN(error ? RESULT_INCONSISTENT : RESULT_SUCCESS);
}


std::pair<int,my_off_t>
MYSQL_BIN_LOG::flush_thread_caches(THD *thd)
{
  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
  my_off_t bytes= 0;
  bool wrote_xid= false;
  int error= cache_mngr->flush(thd, &bytes, &wrote_xid);
  if (!error && bytes > 0)
  {
    /*
      Note that set_trans_pos does not copy the file name. See
      this function documentation for more info.
    */
    thd->set_trans_pos(log_file_name, my_b_tell(&log_file));
    if (wrote_xid)
      inc_prep_xids(thd);
  }
  DBUG_PRINT("debug", ("bytes: %llu", bytes));
  return std::make_pair(error, bytes);
}


int
MYSQL_BIN_LOG::process_flush_stage_queue(my_off_t *total_bytes_var,
                                         bool *rotate_var,
                                         THD **out_queue_var)
{
  DBUG_ASSERT(total_bytes_var && rotate_var && out_queue_var);
  my_off_t total_bytes= 0;
  int flush_error= 1;
  mysql_mutex_assert_owner(&LOCK_log);

  my_atomic_rwlock_rdlock(&opt_binlog_max_flush_queue_time_lock);
  const ulonglong max_udelay= my_atomic_load32(&opt_binlog_max_flush_queue_time);
  my_atomic_rwlock_rdunlock(&opt_binlog_max_flush_queue_time_lock);
  const ulonglong start_utime= max_udelay > 0 ? my_micro_time() : 0;

  /*
    First we read the queue until it either is empty or the difference
    between the time we started and the current time is too large.

    We remember the first thread we unqueued, because this will be the
    beginning of the out queue.
   */
  bool has_more= true;
  THD *first_seen= NULL;
  while ((max_udelay == 0 || my_micro_time() < start_utime + max_udelay) && has_more)
  {
    std::pair<bool,THD*> current= stage_manager.pop_front(Stage_manager::FLUSH_STAGE);
    std::pair<int,my_off_t> result= flush_thread_caches(current.second);
    has_more= current.first;
    total_bytes+= result.second;
    if (flush_error == 1)
      flush_error= result.first;
    if (first_seen == NULL)
      first_seen= current.second;
  }

  /*
    Either the queue is empty, or we ran out of time. If we ran out of
    time, we have to fetch the entire queue (and flush it) since
    otherwise the next batch will not have a leader.
   */
  if (has_more)
  {
    THD *queue= stage_manager.fetch_queue_for(Stage_manager::FLUSH_STAGE);
    for (THD *head= queue ; head ; head = head->next_to_commit)
    {
      std::pair<int,my_off_t> result= flush_thread_caches(head);
      total_bytes+= result.second;
      if (flush_error == 1)
        flush_error= result.first;
    }
    if (first_seen == NULL)
      first_seen= queue;
  }

  *out_queue_var= first_seen;
  *total_bytes_var= total_bytes;
  if (total_bytes > 0 && my_b_tell(&log_file) >= (my_off_t) max_size)
    *rotate_var= true;
  return flush_error;
}


void
MYSQL_BIN_LOG::process_commit_stage_queue(THD *thd, THD *first)
{
  mysql_mutex_assert_owner(&LOCK_commit);
  Thread_excursion excursion(thd);
#ifndef DBUG_OFF
  thd->transaction.flags.ready_preempt= 1; // formality by the leader
#endif
  for (THD *head= first ; head ; head = head->next_to_commit)
  {
    DBUG_PRINT("debug", ("Thread ID: %lu, commit_error: %d, flags.pending: %s",
                         head->thread_id, head->commit_error,
                         YESNO(head->transaction.flags.pending)));
    /*
      If flushing failed, set commit_error for the session, skip the
      transaction and proceed with the next transaction instead. This
      will mark all threads as failed, since the flush failed.

      If flush succeeded, attach to the session and commit it in the
      engines.
    */
#ifndef DBUG_OFF
    stage_manager.clear_preempt_status(head);
#endif
    if (head->commit_error == THD::CE_NONE)
    {
      excursion.try_to_attach_to(head);
      bool all= head->transaction.flags.real_commit;
      if (head->transaction.flags.commit_low)
      {
        /* head is parked to have exited append() */
        DBUG_ASSERT(head->transaction.flags.ready_preempt);
        /*
          storage engine commit
        */
        if (ha_commit_low(head, all, false))
          head->commit_error= THD::CE_COMMIT_ERROR;
      }
      DBUG_PRINT("debug", ("commit_error: %d, flags.pending: %s",
                           head->commit_error,
                           YESNO(head->transaction.flags.pending)));
    }
    /*
      Decrement the prepared XID counter after storage engine commit.
      We also need decrement the prepared XID when encountering a
      flush error or session attach error for avoiding 3-way deadlock
      among user thread, rotate thread and dump thread.
    */
    if (head->transaction.flags.xid_written)
      dec_prep_xids(head);
  }
}

void
MYSQL_BIN_LOG::process_after_commit_stage_queue(THD *thd, THD *first)
{
  Thread_excursion excursion(thd);
  for (THD *head= first; head; head= head->next_to_commit)
  {
    if (head->transaction.flags.run_hooks &&
        head->commit_error == THD::CE_NONE)
    {
      excursion.try_to_attach_to(head);
      bool all= head->transaction.flags.real_commit;
      (void) RUN_HOOK(transaction, after_commit, (head, all));
      /*
        When after_commit finished for the transaction, clear the run_hooks flag.
        This allow other parts of the system to check if after_commit was called.
      */
      head->transaction.flags.run_hooks= false;
    }
  }
}

#ifndef DBUG_OFF

static const char* g_stage_name[] = {
  "FLUSH",
  "SYNC",
  "COMMIT",
};
#endif


bool
MYSQL_BIN_LOG::change_stage(THD *thd,
                            Stage_manager::StageID stage, THD *queue,
                            mysql_mutex_t *leave_mutex,
                            mysql_mutex_t *enter_mutex)
{
  DBUG_ENTER("MYSQL_BIN_LOG::change_stage");
  DBUG_PRINT("enter", ("thd: 0x%llx, stage: %s, queue: 0x%llx",
                       (ulonglong) thd, g_stage_name[stage], (ulonglong) queue));
  DBUG_ASSERT(0 <= stage && stage < Stage_manager::STAGE_COUNTER);
  DBUG_ASSERT(enter_mutex);
  DBUG_ASSERT(queue);
  /*
    enroll_for will release the leave_mutex once the sessions are
    queued.
  */
  if (!stage_manager.enroll_for(stage, queue, leave_mutex))
  {
    DBUG_ASSERT(!thd_get_cache_mngr(thd)->dbug_any_finalized());
    DBUG_RETURN(true);
  }
  mysql_mutex_lock(enter_mutex);
  DBUG_RETURN(false);
}



int
MYSQL_BIN_LOG::flush_cache_to_file(my_off_t *end_pos_var)
{
  if (flush_io_cache(&log_file))
    return ER_ERROR_ON_WRITE;
  *end_pos_var= my_b_tell(&log_file);
  return 0;
}


std::pair<bool, bool>
MYSQL_BIN_LOG::sync_binlog_file(bool force)
{
  bool synced= false;
  unsigned int sync_period= get_sync_period();
  if (force || (sync_period && ++sync_counter >= sync_period))
  {
    sync_counter= 0;
    if (mysql_file_sync(log_file.file, MYF(MY_WME)))
      return std::make_pair(true, synced);
    synced= true;
  }
  return std::make_pair(false, synced);
}


int
MYSQL_BIN_LOG::finish_commit(THD *thd)
{
  if (thd->transaction.flags.commit_low)
  {
    const bool all= thd->transaction.flags.real_commit;
    /*
      storage engine commit
    */
    if (thd->commit_error == THD::CE_NONE &&
        ha_commit_low(thd, all, false))
      thd->commit_error= THD::CE_COMMIT_ERROR;
    /*
      Decrement the prepared XID counter after storage engine commit
    */
    if (thd->transaction.flags.xid_written)
      dec_prep_xids(thd);
    /*
      If commit succeeded, we call the after_commit hook
    */
    if (thd->commit_error == THD::CE_NONE)
    {
      (void) RUN_HOOK(transaction, after_commit, (thd, all));
      thd->transaction.flags.run_hooks= false;
    }
  }
  else if (thd->transaction.flags.xid_written)
    dec_prep_xids(thd);

  /*
    Remove committed GTID from owned_gtids, it was already logged on
    MYSQL_BIN_LOG::write_cache().
  */
  global_sid_lock->rdlock();
  gtid_state->update_on_commit(thd);
  global_sid_lock->unlock();

  DBUG_ASSERT(thd->commit_error || !thd->transaction.flags.run_hooks);
  DBUG_ASSERT(!thd_get_cache_mngr(thd)->dbug_any_finalized());
  DBUG_PRINT("return", ("Thread ID: %lu, commit_error: %d",
                        thd->thread_id, thd->commit_error));
  return thd->commit_error;
}


int MYSQL_BIN_LOG::ordered_commit(THD *thd, bool all, bool skip_commit)
{
  DBUG_ENTER("MYSQL_BIN_LOG::ordered_commit");
  int flush_error= 0;
  my_off_t total_bytes= 0;
  bool do_rotate= false;

  /*
    These values are used while flushing a transaction, so clear
    everything.

    Notes:

    - It would be good if we could keep transaction coordinator
      log-specific data out of the THD structure, but that is not the
      case right now.

    - Everything in the transaction structure is reset when calling
      ha_commit_low since that calls st_transaction::cleanup.
  */
  thd->transaction.flags.pending= true;
  thd->commit_error= THD::CE_NONE;
  thd->next_to_commit= NULL;
  thd->durability_property= HA_IGNORE_DURABILITY;
  thd->transaction.flags.real_commit= all;
  thd->transaction.flags.xid_written= false;
  thd->transaction.flags.commit_low= !skip_commit;
  thd->transaction.flags.run_hooks= !skip_commit;
#ifndef DBUG_OFF
  /*
     The group commit Leader may have to wait for follower whose transaction
     is not ready to be preempted. Initially the status is pessimistic.
     Preemption guarding logics is necessary only when DBUG_ON is set.
     It won't be required for the dbug-off case as long as the follower won't
     execute any thread-specific write access code in this method, which is
     the case as of current.
  */
  thd->transaction.flags.ready_preempt= 0;
#endif

  DBUG_PRINT("enter", ("flags.pending: %s, commit_error: %d, thread_id: %lu",
                       YESNO(thd->transaction.flags.pending),
                       thd->commit_error, thd->thread_id));

  /*
    Stage #1: flushing transactions to binary log

    While flushing, we allow new threads to enter and will process
    them in due time. Once the queue was empty, we cannot reap
    anything more since it is possible that a thread entered and
    appointed itself leader for the flush phase.
  */
  if (change_stage(thd, Stage_manager::FLUSH_STAGE, thd, NULL, &LOCK_log))
  {
    DBUG_PRINT("return", ("Thread ID: %lu, commit_error: %d",
                          thd->thread_id, thd->commit_error));
    DBUG_RETURN(finish_commit(thd));
  }

  THD *wait_queue= NULL;
  flush_error= process_flush_stage_queue(&total_bytes, &do_rotate, &wait_queue);

  my_off_t flush_end_pos= 0;
  if (flush_error == 0 && total_bytes > 0)
    flush_error= flush_cache_to_file(&flush_end_pos);

  /*
    If the flush finished successfully, we can call the after_flush
    hook. Being invoked here, we have the guarantee that the hook is
    executed before the before/after_send_hooks on the dump thread
    preventing race conditions among these plug-ins.
  */
  if (flush_error == 0)
  {
    const char *file_name_ptr= log_file_name + dirname_length(log_file_name);
    DBUG_ASSERT(flush_end_pos != 0);
    if (RUN_HOOK(binlog_storage, after_flush,
                 (thd, file_name_ptr, flush_end_pos)))
    {
      sql_print_error("Failed to run 'after_flush' hooks");
      flush_error= ER_ERROR_ON_WRITE;
    }

    signal_update();
    DBUG_EXECUTE_IF("crash_commit_after_log", DBUG_SUICIDE(););
  }

  /*
    Stage #2: Syncing binary log file to disk
  */
  if (change_stage(thd, Stage_manager::SYNC_STAGE, wait_queue, &LOCK_log, &LOCK_sync))
  {
    DBUG_PRINT("return", ("Thread ID: %lu, commit_error: %d",
                          thd->thread_id, thd->commit_error));
    DBUG_RETURN(finish_commit(thd));
  }
  THD *final_queue= stage_manager.fetch_queue_for(Stage_manager::SYNC_STAGE);
  if (flush_error == 0 && total_bytes > 0)
  {
    std::pair<bool, bool> result= sync_binlog_file(false);
    flush_error= result.first;
  }

  /*
    Stage #3: Commit all transactions in order.

    This stage is skipped if we do not need to order the commits and
    each thread have to execute the handlerton commit instead.

    Howver, since we are keeping the lock from the previous stage, we
    need to unlock it if we skip the stage.
   */
  if (opt_binlog_order_commits)
  {
    if (change_stage(thd, Stage_manager::COMMIT_STAGE,
                     final_queue, &LOCK_sync, &LOCK_commit))
    {
      DBUG_PRINT("return", ("Thread ID: %lu, commit_error: %d",
                            thd->thread_id, thd->commit_error));
      DBUG_RETURN(finish_commit(thd));
    }
    THD *commit_queue= stage_manager.fetch_queue_for(Stage_manager::COMMIT_STAGE);
    DBUG_EXECUTE_IF("semi_sync_3-way_deadlock",
                    DEBUG_SYNC(thd, "before_process_commit_stage_queue"););
    process_commit_stage_queue(thd, commit_queue);
    mysql_mutex_unlock(&LOCK_commit);
    /*
      Process after_commit after LOCK_commit is released for avoiding
      3-way deadlock among user thread, rotate thread and dump thread.
    */
    process_after_commit_stage_queue(thd, commit_queue);
    final_queue= commit_queue;
  }
  else
    mysql_mutex_unlock(&LOCK_sync);

  /* Commit done so signal all waiting threads */
  stage_manager.signal_done(final_queue);

  /*
    Finish the commit before executing a rotate, or run the risk of a
    deadlock. We don't need the return value here since it is in
    thd->commit_error, which is returned below.
  */
  (void) finish_commit(thd);

  /*
    If we need to rotate, we do it without commit error.
    Otherwise the thd->commit_error will be possibly reset.
   */
  if (do_rotate && thd->commit_error == THD::CE_NONE)
  {
    /*
      Do not force the rotate as several consecutive groups may
      request unnecessary rotations.

      NOTE: Run purge_logs wo/ holding LOCK_log because it does not
      need the mutex. Otherwise causes various deadlocks.
    */

    DBUG_EXECUTE_IF("crash_commit_before_unlog", DBUG_SUICIDE(););
    DEBUG_SYNC(thd, "ready_to_do_rotation");
    bool check_purge= false;
    mysql_mutex_lock(&LOCK_log);
    int error= rotate(false, &check_purge);
    mysql_mutex_unlock(&LOCK_log);

    if (error)
      thd->commit_error= THD::CE_COMMIT_ERROR;
    else if (check_purge)
      purge();
  }
  DBUG_RETURN(thd->commit_error);
}


int MYSQL_BIN_LOG::recover(IO_CACHE *log, Format_description_log_event *fdle,
                            my_off_t *valid_pos)
{
  Log_event  *ev;
  HASH xids;
  MEM_ROOT mem_root;
  /*
    The flag is used for handling the case that a transaction
    is partially written to the binlog.
  */
  bool in_transaction= FALSE;

  if (! fdle->is_valid() ||
      my_hash_init(&xids, &my_charset_bin, TC_LOG_PAGE_SIZE/3, 0,
                   sizeof(my_xid), 0, 0, MYF(0)))
    goto err1;

  init_alloc_root(&mem_root, TC_LOG_PAGE_SIZE, TC_LOG_PAGE_SIZE);

  while ((ev= Log_event::read_log_event(log, 0, fdle, TRUE))
         && ev->is_valid())
  {
    if (ev->get_type_code() == QUERY_EVENT &&
        !strcmp(((Query_log_event*)ev)->query, "BEGIN"))
      in_transaction= TRUE;

    if (ev->get_type_code() == QUERY_EVENT &&
        !strcmp(((Query_log_event*)ev)->query, "COMMIT"))
    {
      DBUG_ASSERT(in_transaction == TRUE);
      in_transaction= FALSE;
    }
    else if (ev->get_type_code() == XID_EVENT)
    {
      DBUG_ASSERT(in_transaction == TRUE);
      in_transaction= FALSE;
      Xid_log_event *xev=(Xid_log_event *)ev;
      uchar *x= (uchar *) memdup_root(&mem_root, (uchar*) &xev->xid,
                                      sizeof(xev->xid));
      if (!x || my_hash_insert(&xids, x))
        goto err2;
    }

    /*
      Recorded valid position for the crashed binlog file
      which did not contain incorrect events. The following
      positions increase the variable valid_pos:

      1 -
        ...
        <---> HERE IS VALID <--->
        GTID 
        BEGIN
        ...
        COMMIT
        ...
         
      2 -
        ...
        <---> HERE IS VALID <--->
        GTID 
        DDL/UTILITY
        ...

      In other words, the following positions do not increase
      the variable valid_pos:

      1 -
        GTID 
        <---> HERE IS VALID <--->
        ...

      2 -
        GTID 
        BEGIN
        <---> HERE IS VALID <--->
        ...
    */
    if (!log->error && !in_transaction &&
        !is_gtid_event(ev))
      *valid_pos= my_b_tell(log);

    delete ev;
  }

  if (ha_recover(&xids))
    goto err2;

  free_root(&mem_root, MYF(0));
  my_hash_free(&xids);
  return 0;

err2:
  free_root(&mem_root, MYF(0));
  my_hash_free(&xids);
err1:
  sql_print_error("Crash recovery failed. Either correct the problem "
                  "(if it's, for example, out of memory error) and restart, "
                  "or delete (or rename) binary log and start mysqld with "
                  "--tc-heuristic-recover={commit|rollback}");
  return 1;
}

Group_cache *THD::get_group_cache(bool is_transactional)
{
  DBUG_ENTER("THD::get_group_cache(bool)");

  // If opt_bin_log==0, it is not safe to call thd_get_cache_mngr
  // because binlog_hton has not been completely set up.
  DBUG_ASSERT(opt_bin_log);
  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(this);

  // cache_mngr is NULL until we call thd->binlog_setup_trx_data, so
  // we assert that this has been done.
  DBUG_ASSERT(cache_mngr != NULL);

  binlog_cache_data *cache_data=
    cache_mngr->get_binlog_cache_data(is_transactional);
  DBUG_ASSERT(cache_data != NULL);

  DBUG_RETURN(&cache_data->group_cache);
}

/*
  These functions are placed in this file since they need access to
  binlog_hton, which has internal linkage.
*/

int THD::binlog_setup_trx_data()
{
  DBUG_ENTER("THD::binlog_setup_trx_data");
  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(this);

  if (cache_mngr)
    DBUG_RETURN(0);                             // Already set up

  cache_mngr= (binlog_cache_mngr*) my_malloc(sizeof(binlog_cache_mngr), MYF(MY_ZEROFILL));
  if (!cache_mngr ||
      open_cached_file(&cache_mngr->stmt_cache.cache_log, mysql_tmpdir,
                       LOG_PREFIX, binlog_stmt_cache_size, MYF(MY_WME)) ||
      open_cached_file(&cache_mngr->trx_cache.cache_log, mysql_tmpdir,
                       LOG_PREFIX, binlog_cache_size, MYF(MY_WME)))
  {
    my_free(cache_mngr);
    DBUG_RETURN(1);                      // Didn't manage to set it up
  }
  DBUG_PRINT("debug", ("Set ha_data slot %d to 0x%llx", binlog_hton->slot, (ulonglong) cache_mngr));
  thd_set_ha_data(this, binlog_hton, cache_mngr);

  cache_mngr= new (thd_get_cache_mngr(this))
              binlog_cache_mngr(max_binlog_stmt_cache_size,
                                &binlog_stmt_cache_use,
                                &binlog_stmt_cache_disk_use,
                                max_binlog_cache_size,
                                &binlog_cache_use,
                                &binlog_cache_disk_use);
  DBUG_RETURN(0);
}

void register_binlog_handler(THD *thd, bool trx)
{
  DBUG_ENTER("register_binlog_handler");
  /*
    If this is the first call to this function while processing a statement,
    the transactional cache does not have a savepoint defined. So, in what
    follows:
      . an implicit savepoint is defined;
      . callbacks are registered;
      . binary log is set as read/write.

    The savepoint allows for truncating the trx-cache transactional changes
    fail. Callbacks are necessary to flush caches upon committing or rolling
    back a statement or a transaction. However, notifications do not happen
    if the binary log is set as read/write.
  */
  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
  if (cache_mngr->trx_cache.get_prev_position() == MY_OFF_T_UNDEF)
  {
    /*
      Set an implicit savepoint in order to be able to truncate a trx-cache.
    */
    my_off_t pos= 0;
    binlog_trans_log_savepos(thd, &pos);
    cache_mngr->trx_cache.set_prev_position(pos);

    /*
      Set callbacks in order to be able to call commmit or rollback.
    */
    if (trx)
      trans_register_ha(thd, TRUE, binlog_hton);
    trans_register_ha(thd, FALSE, binlog_hton);

    /*
      Set the binary log as read/write otherwise callbacks are not called.
    */
    thd->ha_data[binlog_hton->slot].ha_info[0].set_trx_read_write();
  }
  DBUG_VOID_RETURN;
}

static int binlog_start_trans_and_stmt(THD *thd, Log_event *start_event)
{
  DBUG_ENTER("binlog_start_trans_and_stmt");
 
  /*
    Initialize the cache manager if this was not done yet.
  */ 
  if (thd->binlog_setup_trx_data())
    DBUG_RETURN(1);

  /*
    Retrieve the appropriated cache.
  */
  bool is_transactional= start_event->is_using_trans_cache();
  binlog_cache_mngr *cache_mngr= thd_get_cache_mngr(thd);
  binlog_cache_data *cache_data= cache_mngr->get_binlog_cache_data(is_transactional);
 
  /*
    If the event is requesting immediatly logging, there is no need to go
    further down and set savepoint and register callbacks.
  */ 
  if (start_event->is_using_immediate_logging())
    DBUG_RETURN(0);

  register_binlog_handler(thd, thd->in_multi_stmt_transaction_mode());

  /*
    If the cache is empty log "BEGIN" at the beginning of every transaction.
    Here, a transaction is either a BEGIN..COMMIT/ROLLBACK block or a single
    statement in autocommit mode.
  */
  if (cache_data->is_binlog_empty())
  {
    Query_log_event qinfo(thd, STRING_WITH_LEN("BEGIN"),
                          is_transactional, FALSE, TRUE, 0, TRUE);
    if (cache_data->write_event(thd, &qinfo))
      DBUG_RETURN(1);
  }

  DBUG_RETURN(0);
}

int THD::binlog_write_table_map(TABLE *table, bool is_transactional,
                                bool binlog_rows_query)
{
  int error;
  DBUG_ENTER("THD::binlog_write_table_map");
  DBUG_PRINT("enter", ("table: 0x%lx  (%s: #%llu)",
                       (long) table, table->s->table_name.str,
                       table->s->table_map_id.id()));

  /* Pre-conditions */
  DBUG_ASSERT(is_current_stmt_binlog_format_row() && mysql_bin_log.is_open());
  DBUG_ASSERT(table->s->table_map_id.is_valid());

  Table_map_log_event
    the_event(this, table, table->s->table_map_id, is_transactional);

  binlog_start_trans_and_stmt(this, &the_event);

  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(this);

  binlog_cache_data *cache_data=
    cache_mngr->get_binlog_cache_data(is_transactional);

  if (binlog_rows_query && this->query())
  {
    /* Write the Rows_query_log_event into binlog before the table map */
    Rows_query_log_event
      rows_query_ev(this, this->query(), this->query_length());
    if ((error= cache_data->write_event(this, &rows_query_ev)))
      DBUG_RETURN(error);
  }

  if ((error= cache_data->write_event(this, &the_event)))
    DBUG_RETURN(error);

  binlog_table_maps++;
  DBUG_RETURN(0);
}

Rows_log_event*
THD::binlog_get_pending_rows_event(bool is_transactional) const
{
  Rows_log_event* rows= NULL;
  binlog_cache_mngr *const cache_mngr= thd_get_cache_mngr(this);

  /*
    This is less than ideal, but here's the story: If there is no cache_mngr,
    prepare_pending_rows_event() has never been called (since the cache_mngr
    is set up there). In that case, we just return NULL.
   */
  if (cache_mngr)
  {
    binlog_cache_data *cache_data=
      cache_mngr->get_binlog_cache_data(is_transactional);

    rows= cache_data->pending();
  }
  return (rows);
}

void
THD::add_to_binlog_accessed_dbs(const char *db_param)
{
  char *after_db;
  MEM_ROOT *db_mem_root= &main_mem_root;

  if (!binlog_accessed_db_names)
    binlog_accessed_db_names= new (db_mem_root) List<char>;

  if (binlog_accessed_db_names->elements >  MAX_DBS_IN_EVENT_MTS)
  {
    push_warning_printf(this, Sql_condition::WARN_LEVEL_WARN,
                        ER_MTS_UPDATED_DBS_GREATER_MAX,
                        ER(ER_MTS_UPDATED_DBS_GREATER_MAX),
                        MAX_DBS_IN_EVENT_MTS);
    return;
  }

  after_db= strdup_root(db_mem_root, db_param);

  /* 
     sorted insertion is implemented with first rearranging data
     (pointer to char*) of the links and final appending of the least
     ordered data to create a new link in the list.
  */
  if (binlog_accessed_db_names->elements != 0)
  {
    List_iterator<char> it(*get_binlog_accessed_db_names());

    while (it++)
    {
      char *swap= NULL;
      char **ref_cur_db= it.ref();
      int cmp= strcmp(after_db, *ref_cur_db);

      DBUG_ASSERT(!swap || cmp < 0);
      
      if (cmp == 0)
      {
        after_db= NULL;  /* dup to ignore */
        break;
      }
      else if (swap || cmp > 0)
      {
        swap= *ref_cur_db;
        *ref_cur_db= after_db;
        after_db= swap;
      }
    }
  }
  if (after_db)
    binlog_accessed_db_names->push_back(after_db, &main_mem_root);
}


int THD::decide_logging_format(TABLE_LIST *tables)
{
  DBUG_ENTER("THD::decide_logging_format");
  DBUG_PRINT("info", ("query: %s", query()));
  DBUG_PRINT("info", ("variables.binlog_format: %lu",
                      variables.binlog_format));
  DBUG_PRINT("info", ("lex->get_stmt_unsafe_flags(): 0x%x",
                      lex->get_stmt_unsafe_flags()));

  reset_binlog_local_stmt_filter();

  /*
    We should not decide logging format if the binlog is closed or
    binlogging is off, or if the statement is filtered out from the
    binlog by filtering rules.
  */
  if (mysql_bin_log.is_open() && (variables.option_bits & OPTION_BIN_LOG) &&
      !(variables.binlog_format == BINLOG_FORMAT_STMT &&
        !binlog_filter->db_ok(db)))
  {
    /*
      Compute one bit field with the union of all the engine
      capabilities, and one with the intersection of all the engine
      capabilities.
    */
    handler::Table_flags flags_write_some_set= 0;
    handler::Table_flags flags_access_some_set= 0;
    handler::Table_flags flags_write_all_set=
      HA_BINLOG_ROW_CAPABLE | HA_BINLOG_STMT_CAPABLE;

    /* 
       If different types of engines are about to be updated.
       For example: Innodb and Falcon; Innodb and MyIsam.
    */
    my_bool multi_write_engine= FALSE;
    /*
       If different types of engines are about to be accessed 
       and any of them is about to be updated. For example:
       Innodb and Falcon; Innodb and MyIsam.
    */
    my_bool multi_access_engine= FALSE;
    /*
       Identifies if a table is changed.
    */
    my_bool is_write= FALSE;
    /*
       A pointer to a previous table that was changed.
    */
    TABLE* prev_write_table= NULL;
    /*
       A pointer to a previous table that was accessed.
    */
    TABLE* prev_access_table= NULL;
    /*
      True if at least one table is transactional.
    */
    bool write_to_some_transactional_table= false;
    /*
      True if at least one table is non-transactional.
    */
    bool write_to_some_non_transactional_table= false;
    /*
       True if all non-transactional tables that has been updated
       are temporary.
    */
    bool write_all_non_transactional_are_tmp_tables= true;
    uint replicated_tables_count= 0;
    uint non_replicated_tables_count= 0;
#ifndef DBUG_OFF
    {
      static const char *prelocked_mode_name[] = {
        "NON_PRELOCKED",
        "PRELOCKED",
        "PRELOCKED_UNDER_LOCK_TABLES",
      };
      DBUG_PRINT("debug", ("prelocked_mode: %s",
                           prelocked_mode_name[locked_tables_mode]));
    }
#endif

    /*
      Get the capabilities vector for all involved storage engines and
      mask out the flags for the binary log.
    */
    for (TABLE_LIST *table= tables; table; table= table->next_global)
    {
      if (table->placeholder())
        continue;

      handler::Table_flags const flags= table->table->file->ha_table_flags();

      DBUG_PRINT("info", ("table: %s; ha_table_flags: 0x%llx",
                          table->table_name, flags));

      if (table->table->no_replicate)
      {
        /*
          The statement uses a table that is not replicated.
          The following properties about the table:
          - persistent / transient
          - transactional / non transactional
          - temporary / permanent
          - read or write
          - multiple engines involved because of this table
          are not relevant, as this table is completely ignored.
          Because the statement uses a non replicated table,
          using STATEMENT format in the binlog is impossible.
          Either this statement will be discarded entirely,
          or it will be logged (possibly partially) in ROW format.
        */
        lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_SYSTEM_TABLE);

        if (table->lock_type >= TL_WRITE_ALLOW_WRITE)
        {
          non_replicated_tables_count++;
          continue;
        }
      }

      replicated_tables_count++;

      my_bool trans= table->table->file->has_transactions();

      if (table->lock_type >= TL_WRITE_ALLOW_WRITE)
      {
        write_to_some_transactional_table=
          write_to_some_transactional_table || trans;

        write_to_some_non_transactional_table=
          write_to_some_non_transactional_table || !trans;

        if (prev_write_table && prev_write_table->file->ht !=
            table->table->file->ht)
          multi_write_engine= TRUE;

        if (table->table->s->tmp_table)
          lex->set_stmt_accessed_table(trans ? LEX::STMT_WRITES_TEMP_TRANS_TABLE :
                                               LEX::STMT_WRITES_TEMP_NON_TRANS_TABLE);
        else
          lex->set_stmt_accessed_table(trans ? LEX::STMT_WRITES_TRANS_TABLE :
                                               LEX::STMT_WRITES_NON_TRANS_TABLE);

        /*
         Non-transactional updates are allowed when row binlog format is
         used and all non-transactional tables are temporary.
         Binlog format is checked on THD::is_dml_gtid_compatible() method.
        */
        if (!trans)
          write_all_non_transactional_are_tmp_tables=
            write_all_non_transactional_are_tmp_tables &&
            table->table->s->tmp_table;

        flags_write_all_set &= flags;
        flags_write_some_set |= flags;
        is_write= TRUE;

        prev_write_table= table->table;
      }
      flags_access_some_set |= flags;

      if (lex->sql_command != SQLCOM_CREATE_TABLE ||
          (lex->sql_command == SQLCOM_CREATE_TABLE &&
          (lex->create_info.options & HA_LEX_CREATE_TMP_TABLE)))
      {
        if (table->table->s->tmp_table)
          lex->set_stmt_accessed_table(trans ? LEX::STMT_READS_TEMP_TRANS_TABLE :
                                               LEX::STMT_READS_TEMP_NON_TRANS_TABLE);
        else
          lex->set_stmt_accessed_table(trans ? LEX::STMT_READS_TRANS_TABLE :
                                               LEX::STMT_READS_NON_TRANS_TABLE);
      }

      if (prev_access_table && prev_access_table->file->ht !=
          table->table->file->ht)
         multi_access_engine= TRUE;

      prev_access_table= table->table;
    }
    DBUG_ASSERT(!is_write ||
                write_to_some_transactional_table ||
                write_to_some_non_transactional_table);
    /*
      write_all_non_transactional_are_tmp_tables may be true if any
      non-transactional table was not updated, so we fix its value here.
    */
    write_all_non_transactional_are_tmp_tables=
      write_all_non_transactional_are_tmp_tables &&
      write_to_some_non_transactional_table;

    DBUG_PRINT("info", ("flags_write_all_set: 0x%llx", flags_write_all_set));
    DBUG_PRINT("info", ("flags_write_some_set: 0x%llx", flags_write_some_set));
    DBUG_PRINT("info", ("flags_access_some_set: 0x%llx", flags_access_some_set));
    DBUG_PRINT("info", ("multi_write_engine: %d", multi_write_engine));
    DBUG_PRINT("info", ("multi_access_engine: %d", multi_access_engine));

    int error= 0;
    int unsafe_flags;

    bool multi_stmt_trans= in_multi_stmt_transaction_mode();
    bool trans_table= trans_has_updated_trans_table(this);
    bool binlog_direct= variables.binlog_direct_non_trans_update;

    if (lex->is_mixed_stmt_unsafe(multi_stmt_trans, binlog_direct,
                                  trans_table, tx_isolation))
      lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_MIXED_STATEMENT);
    else if (multi_stmt_trans && trans_table && !binlog_direct &&
             lex->stmt_accessed_table(LEX::STMT_WRITES_NON_TRANS_TABLE))
      lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_NONTRANS_AFTER_TRANS);

    /*
      If more than one engine is involved in the statement and at
      least one is doing it's own logging (is *self-logging*), the
      statement cannot be logged atomically, so we generate an error
      rather than allowing the binlog to become corrupt.
    */
    if (multi_write_engine &&
        (flags_write_some_set & HA_HAS_OWN_BINLOGGING))
      my_error((error= ER_BINLOG_MULTIPLE_ENGINES_AND_SELF_LOGGING_ENGINE),
               MYF(0));
    else if (multi_access_engine && flags_access_some_set & HA_HAS_OWN_BINLOGGING)
      lex->set_stmt_unsafe(LEX::BINLOG_STMT_UNSAFE_MULTIPLE_ENGINES_AND_SELF_LOGGING_ENGINE);

    /* both statement-only and row-only engines involved */
    if ((flags_write_all_set & (HA_BINLOG_STMT_CAPABLE | HA_BINLOG_ROW_CAPABLE)) == 0)
    {
      /*
        1. Error: Binary logging impossible since both row-incapable
           engines and statement-incapable engines are involved
      */
      my_error((error= ER_BINLOG_ROW_ENGINE_AND_STMT_ENGINE), MYF(0));
    }
    /* statement-only engines involved */
    else if ((flags_write_all_set & HA_BINLOG_ROW_CAPABLE) == 0)
    {
      if (lex->is_stmt_row_injection())
      {
        /*
          4. Error: Cannot execute row injection since table uses
             storage engine limited to statement-logging
        */
        my_error((error= ER_BINLOG_ROW_INJECTION_AND_STMT_ENGINE), MYF(0));
      }
      else if (variables.binlog_format == BINLOG_FORMAT_ROW &&
               sqlcom_can_generate_row_events(this))
      {
        /*
          2. Error: Cannot modify table that uses a storage engine
             limited to statement-logging when BINLOG_FORMAT = ROW
        */
        my_error((error= ER_BINLOG_ROW_MODE_AND_STMT_ENGINE), MYF(0));
      }
      else if ((unsafe_flags= lex->get_stmt_unsafe_flags()) != 0)
      {
        /*
          3. Error: Cannot execute statement: binlogging of unsafe
             statement is impossible when storage engine is limited to
             statement-logging and BINLOG_FORMAT = MIXED.
        */
        for (int unsafe_type= 0;
             unsafe_type < LEX::BINLOG_STMT_UNSAFE_COUNT;
             unsafe_type++)
          if (unsafe_flags & (1 << unsafe_type))
            my_error((error= ER_BINLOG_UNSAFE_AND_STMT_ENGINE), MYF(0),
                     ER(LEX::binlog_stmt_unsafe_errcode[unsafe_type]));
      }
      /* log in statement format! */
    }
    /* no statement-only engines */
    else
    {
      /* binlog_format = STATEMENT */
      if (variables.binlog_format == BINLOG_FORMAT_STMT)
      {
        if (lex->is_stmt_row_injection())
        {
          /*
            6. Error: Cannot execute row injection since
               BINLOG_FORMAT = STATEMENT
          */
          my_error((error= ER_BINLOG_ROW_INJECTION_AND_STMT_MODE), MYF(0));
        }
        else if ((flags_write_all_set & HA_BINLOG_STMT_CAPABLE) == 0 &&
                 sqlcom_can_generate_row_events(this))
        {
          /*
            5. Error: Cannot modify table that uses a storage engine
               limited to row-logging when binlog_format = STATEMENT
          */
          my_error((error= ER_BINLOG_STMT_MODE_AND_ROW_ENGINE), MYF(0), "");
        }
        else if (is_write && (unsafe_flags= lex->get_stmt_unsafe_flags()) != 0)
        {
          /*
            7. Warning: Unsafe statement logged as statement due to
               binlog_format = STATEMENT
          */
          binlog_unsafe_warning_flags|= unsafe_flags;
          DBUG_PRINT("info", ("Scheduling warning to be issued by "
                              "binlog_query: '%s'",
                              ER(ER_BINLOG_UNSAFE_STATEMENT)));
          DBUG_PRINT("info", ("binlog_unsafe_warning_flags: 0x%x",
                              binlog_unsafe_warning_flags));
        }
        /* log in statement format! */
      }
      /* No statement-only engines and binlog_format != STATEMENT.
         I.e., nothing prevents us from row logging if needed. */
      else
      {
        if (lex->is_stmt_unsafe() || lex->is_stmt_row_injection()
            || (flags_write_all_set & HA_BINLOG_STMT_CAPABLE) == 0)
        {
          /* log in row format! */
          set_current_stmt_binlog_format_row_if_mixed();
        }
      }
    }

    if (non_replicated_tables_count > 0)
    {
      if ((replicated_tables_count == 0) || ! is_write)
      {
        DBUG_PRINT("info", ("decision: no logging, no replicated table affected"));
        set_binlog_local_stmt_filter();
      }
      else
      {
        if (! is_current_stmt_binlog_format_row())
        {
          my_error((error= ER_BINLOG_STMT_MODE_AND_NO_REPL_TABLES), MYF(0));
        }
        else
        {
          clear_binlog_local_stmt_filter();
        }
      }
    }
    else
    {
      clear_binlog_local_stmt_filter();
    }

    if (!error && enforce_gtid_consistency &&
        !is_dml_gtid_compatible(write_to_some_transactional_table,
                                write_to_some_non_transactional_table,
                                write_all_non_transactional_are_tmp_tables))
      error= 1;

    if (error) {
      DBUG_PRINT("info", ("decision: no logging since an error was generated"));
      DBUG_RETURN(-1);
    }

    if (is_write &&
        lex->sql_command != SQLCOM_END /* rows-event applying by slave */)
    {
      /*
        Master side of DML in the STMT format events parallelization.
        All involving table db:s are stored in a abc-ordered name list.
        In case the number of databases exceeds MAX_DBS_IN_EVENT_MTS maximum
        the list gathering breaks since it won't be sent to the slave.
      */
      for (TABLE_LIST *table= tables; table; table= table->next_global)
      {
        if (table->placeholder())
          continue;

        DBUG_ASSERT(table->table);

        if (table->table->file->referenced_by_foreign_key())
        {
          /* 
             FK-referenced dbs can't be gathered currently. The following
             event will be marked for sequential execution on slave.
          */
          binlog_accessed_db_names= NULL;
          add_to_binlog_accessed_dbs("");
          break;
        }
        if (!is_current_stmt_binlog_format_row())
          add_to_binlog_accessed_dbs(table->db);
      }
    }
    DBUG_PRINT("info", ("decision: logging in %s format",
                        is_current_stmt_binlog_format_row() ?
                        "ROW" : "STATEMENT"));

    if (variables.binlog_format == BINLOG_FORMAT_ROW &&
        (lex->sql_command == SQLCOM_UPDATE ||
         lex->sql_command == SQLCOM_UPDATE_MULTI ||
         lex->sql_command == SQLCOM_DELETE ||
         lex->sql_command == SQLCOM_DELETE_MULTI))
    {
      String table_names;
      /*
        Generate a warning for UPDATE/DELETE statements that modify a
        BLACKHOLE table, as row events are not logged in row format.
      */
      for (TABLE_LIST *table= tables; table; table= table->next_global)
      {
        if (table->placeholder())
          continue;
        if (table->table->file->ht->db_type == DB_TYPE_BLACKHOLE_DB &&
            table->lock_type >= TL_WRITE_ALLOW_WRITE)
        {
            table_names.append(table->table_name);
            table_names.append(",");
        }
      }
      if (!table_names.is_empty())
      {
        bool is_update= (lex->sql_command == SQLCOM_UPDATE ||
                         lex->sql_command == SQLCOM_UPDATE_MULTI);
        /*
          Replace the last ',' with '.' for table_names
        */
        table_names.replace(table_names.length()-1, 1, ".", 1);
        push_warning_printf(this, Sql_condition::WARN_LEVEL_WARN,
                            WARN_ON_BLOCKHOLE_IN_RBR,
                            ER(WARN_ON_BLOCKHOLE_IN_RBR),
                            is_update ? "UPDATE" : "DELETE",
                            table_names.c_ptr());
      }
    }
  }
#ifndef DBUG_OFF
  else
    DBUG_PRINT("info", ("decision: no logging since "
                        "mysql_bin_log.is_open() = %d "
                        "and (options & OPTION_BIN_LOG) = 0x%llx "
                        "and binlog_format = %lu "
                        "and binlog_filter->db_ok(db) = %d",
                        mysql_bin_log.is_open(),
                        (variables.option_bits & OPTION_BIN_LOG),
                        variables.binlog_format,
                        binlog_filter->db_ok(db)));
#endif

  DBUG_RETURN(0);
}


bool THD::is_ddl_gtid_compatible() const
{
  DBUG_ENTER("THD::is_ddl_gtid_compatible");

  // If @@session.sql_log_bin has been manually turned off (only
  // doable by SUPER), then no problem, we can execute any statement.
  if ((variables.option_bits & OPTION_BIN_LOG) == 0)
    DBUG_RETURN(true);

  if (lex->sql_command == SQLCOM_CREATE_TABLE &&
      !(lex->create_info.options & HA_LEX_CREATE_TMP_TABLE) &&
      lex->select_lex.item_list.elements)
  {
    /*
      CREATE ... SELECT (without TEMPORARY) is unsafe because if
      binlog_format=row it will be logged as a CREATE TABLE followed
      by row events, re-executed non-atomically as two transactions,
      and then written to the slave's binary log as two separate
      transactions with the same GTID.
    */
    my_error(ER_GTID_UNSAFE_CREATE_SELECT, MYF(0));
    DBUG_RETURN(false);
  }
  if ((lex->sql_command == SQLCOM_CREATE_TABLE &&
       (lex->create_info.options & HA_LEX_CREATE_TMP_TABLE) != 0) ||
      (lex->sql_command == SQLCOM_DROP_TABLE && lex->drop_temporary))
  {
    /*
      [CREATE|DROP] TEMPORARY TABLE is unsafe to execute
      inside a transaction because the table will stay and the
      transaction will be written to the slave's binary log with the
      GTID even if the transaction is rolled back.
    */
    if (in_multi_stmt_transaction_mode())
    {
      my_error(ER_GTID_UNSAFE_CREATE_DROP_TEMPORARY_TABLE_IN_TRANSACTION,
               MYF(0));
      DBUG_RETURN(false);
    }
  }
  DBUG_RETURN(true);
}


bool
THD::is_dml_gtid_compatible(bool transactional_table,
                            bool non_transactional_table,
                            bool non_transactional_tmp_tables) const
{
  DBUG_ENTER("THD::is_dml_gtid_compatible(bool, bool, bool)");

  // If @@session.sql_log_bin has been manually turned off (only
  // doable by SUPER), then no problem, we can execute any statement.
  if ((variables.option_bits & OPTION_BIN_LOG) == 0)
    DBUG_RETURN(true);

  /*
    Single non-transactional updates are allowed when not mixed
    together with transactional statements within a transaction.
    Furthermore, writing to transactional and non-transactional
    engines in a single statement is also disallowed.
    Multi-statement transactions on non-transactional tables are
    split into single-statement transactions when
    GTID_NEXT = "AUTOMATIC".

    Non-transactional updates are allowed when row binlog format is
    used and all non-transactional tables are temporary.

    The debug symbol "allow_gtid_unsafe_non_transactional_updates"
    disables the error.  This is useful because it allows us to run
    old tests that were not written with the restrictions of GTIDs in
    mind.
  */
  if (non_transactional_table &&
      (transactional_table || trans_has_updated_trans_table(this)) &&
      !(non_transactional_tmp_tables && is_current_stmt_binlog_format_row()) &&
      !DBUG_EVALUATE_IF("allow_gtid_unsafe_non_transactional_updates", 1, 0))
  {
    my_error(ER_GTID_UNSAFE_NON_TRANSACTIONAL_TABLE, MYF(0));
    DBUG_RETURN(false);
  }

  DBUG_RETURN(true);
}

/*
  Implementation of interface to write rows to the binary log through the
  thread.  The thread is responsible for writing the rows it has
  inserted/updated/deleted.
*/

#ifndef MYSQL_CLIENT

/*
  Template member function for ensuring that there is an rows log
  event of the apropriate type before proceeding.

  PRE CONDITION:
    - Events of type 'RowEventT' have the type code 'type_code'.
    
  POST CONDITION:
    If a non-NULL pointer is returned, the pending event for thread 'thd' will
    be an event of type 'RowEventT' (which have the type code 'type_code')
    will either empty or have enough space to hold 'needed' bytes.  In
    addition, the columns bitmap will be correct for the row, meaning that
    the pending event will be flushed if the columns in the event differ from
    the columns suppled to the function.

  RETURNS
    If no error, a non-NULL pending event (either one which already existed or
    the newly created one).
    If error, NULL.
 */

template <class RowsEventT> Rows_log_event* 
THD::binlog_prepare_pending_rows_event(TABLE* table, uint32 serv_id,
                                       size_t needed,
                                       bool is_transactional,
                                       RowsEventT *hint __attribute__((unused)),
                                       const uchar* extra_row_info)
{
  DBUG_ENTER("binlog_prepare_pending_rows_event");

  /* Fetch the type code for the RowsEventT template parameter */
  int const general_type_code= RowsEventT::TYPE_CODE;

  Rows_log_event* pending= binlog_get_pending_rows_event(is_transactional);

  if (unlikely(pending && !pending->is_valid()))
    DBUG_RETURN(NULL);

  /*
    Check if the current event is non-NULL and a write-rows
    event. Also check if the table provided is mapped: if it is not,
    then we have switched to writing to a new table.
    If there is no pending event, we need to create one. If there is a pending
    event, but it's not about the same table id, or not of the same type
    (between Write, Update and Delete), or not the same affected columns, or
    going to be too big, flush this event to disk and create a new pending
    event.
  */
  if (!pending ||
      pending->server_id != serv_id || 
      pending->get_table_id() != table->s->table_map_id ||
      pending->get_general_type_code() != general_type_code ||
      pending->get_data_size() + needed > opt_binlog_rows_event_max_size ||
      pending->read_write_bitmaps_cmp(table) == FALSE ||
      !binlog_row_event_extra_data_eq(pending->get_extra_row_data(),
                                      extra_row_info))
  {
    /* Create a new RowsEventT... */
    Rows_log_event* const
        ev= new RowsEventT(this, table, table->s->table_map_id,
                           is_transactional, extra_row_info);
    if (unlikely(!ev))
      DBUG_RETURN(NULL);
    ev->server_id= serv_id; // I don't like this, it's too easy to forget.
    /*
      flush the pending event and replace it with the newly created
      event...
    */
    if (unlikely(
        mysql_bin_log.flush_and_set_pending_rows_event(this, ev,
                                                       is_transactional)))
    {
      delete ev;
      DBUG_RETURN(NULL);
    }

    DBUG_RETURN(ev);               /* This is the new pending event */
  }
  DBUG_RETURN(pending);        /* This is the current pending event */
}

/* Declare in unnamed namespace. */
CPP_UNNAMED_NS_START

  class Row_data_memory {
  public:
    Row_data_memory(TABLE *table, size_t const len1)
      : m_memory(0)
    {
#ifndef DBUG_OFF
      m_alloc_checked= FALSE;
#endif
      allocate_memory(table, len1);
      m_ptr[0]= has_memory() ? m_memory : 0;
      m_ptr[1]= 0;
    }

    Row_data_memory(TABLE *table, size_t const len1, size_t const len2)
      : m_memory(0)
    {
#ifndef DBUG_OFF
      m_alloc_checked= FALSE;
#endif
      allocate_memory(table, len1 + len2);
      m_ptr[0]= has_memory() ? m_memory        : 0;
      m_ptr[1]= has_memory() ? m_memory + len1 : 0;
    }

    ~Row_data_memory()
    {
      if (m_memory != 0 && m_release_memory_on_destruction)
        my_free(m_memory);
    }

    bool has_memory() const {
#ifndef DBUG_OFF
      m_alloc_checked= TRUE;
#endif
      return m_memory != 0;
    }

    uchar *slot(uint s)
    {
      DBUG_ASSERT(s < sizeof(m_ptr)/sizeof(*m_ptr));
      DBUG_ASSERT(m_ptr[s] != 0);
      DBUG_ASSERT(m_alloc_checked == TRUE);
      return m_ptr[s];
    }

  private:
    void allocate_memory(TABLE *const table, size_t const total_length)
    {
      if (table->s->blob_fields == 0)
      {
        /*
          The maximum length of a packed record is less than this
          length. We use this value instead of the supplied length
          when allocating memory for records, since we don't know how
          the memory will be used in future allocations.

          Since table->s->reclength is for unpacked records, we have
          to add two bytes for each field, which can potentially be
          added to hold the length of a packed field.
        */
        size_t const maxlen= table->s->reclength + 2 * table->s->fields;

        /*
          Allocate memory for two records if memory hasn't been
          allocated. We allocate memory for two records so that it can
          be used when processing update rows as well.
        */
        if (table->write_row_record == 0)
          table->write_row_record=
            (uchar *) alloc_root(&table->mem_root, 2 * maxlen);
        m_memory= table->write_row_record;
        m_release_memory_on_destruction= FALSE;
      }
      else
      {
        m_memory= (uchar *) my_malloc(total_length, MYF(MY_WME));
        m_release_memory_on_destruction= TRUE;
      }
    }

#ifndef DBUG_OFF
    mutable bool m_alloc_checked;
#endif
    bool m_release_memory_on_destruction;
    uchar *m_memory;
    uchar *m_ptr[2];
  };

CPP_UNNAMED_NS_END

int THD::binlog_write_row(TABLE* table, bool is_trans, 
                          uchar const *record,
                          const uchar* extra_row_info)
{ 
  DBUG_ASSERT(is_current_stmt_binlog_format_row() && mysql_bin_log.is_open());

  /*
    Pack records into format for transfer. We are allocating more
    memory than needed, but that doesn't matter.
  */
  Row_data_memory memory(table, max_row_length(table, record));
  if (!memory.has_memory())
    return HA_ERR_OUT_OF_MEM;

  uchar *row_data= memory.slot(0);

  size_t const len= pack_row(table, table->write_set, row_data, record);

  Rows_log_event* const ev=
    binlog_prepare_pending_rows_event(table, server_id, len, is_trans,
                                      static_cast<Write_rows_log_event*>(0),
                                      extra_row_info);

  if (unlikely(ev == 0))
    return HA_ERR_OUT_OF_MEM;

  return ev->add_row_data(row_data, len);
}

int THD::binlog_update_row(TABLE* table, bool is_trans,
                           const uchar *before_record,
                           const uchar *after_record,
                           const uchar* extra_row_info)
{ 
  DBUG_ASSERT(is_current_stmt_binlog_format_row() && mysql_bin_log.is_open());
  int error= 0;

  MY_BITMAP *old_read_set= table->read_set;
  MY_BITMAP *old_write_set= table->write_set;

  binlog_prepare_row_images(table);

  size_t const before_maxlen = max_row_length(table, before_record);
  size_t const after_maxlen  = max_row_length(table, after_record);

  Row_data_memory row_data(table, before_maxlen, after_maxlen);
  if (!row_data.has_memory())
    return HA_ERR_OUT_OF_MEM;

  uchar *before_row= row_data.slot(0);
  uchar *after_row= row_data.slot(1);

  size_t const before_size= pack_row(table, table->read_set, before_row,
                                        before_record);
  size_t const after_size= pack_row(table, table->write_set, after_row,
                                       after_record);

  /*
    Don't print debug messages when running valgrind since they can
    trigger false warnings.
   */
#ifndef HAVE_purify
  DBUG_DUMP("before_record", before_record, table->s->reclength);
  DBUG_DUMP("after_record",  after_record, table->s->reclength);
  DBUG_DUMP("before_row",    before_row, before_size);
  DBUG_DUMP("after_row",     after_row, after_size);
#endif

  Rows_log_event* const ev=
    binlog_prepare_pending_rows_event(table, server_id,
                                      before_size + after_size, is_trans,
                                      static_cast<Update_rows_log_event*>(0),
                                      extra_row_info);

  if (unlikely(ev == 0))
    return HA_ERR_OUT_OF_MEM;

  error= ev->add_row_data(before_row, before_size) ||
         ev->add_row_data(after_row, after_size);

  /* restore read/write set for the rest of execution */
  table->column_bitmaps_set_no_signal(old_read_set,
                                      old_write_set);

  return error;
}

int THD::binlog_delete_row(TABLE* table, bool is_trans, 
                           uchar const *record,
                           const uchar* extra_row_info)
{ 
  DBUG_ASSERT(is_current_stmt_binlog_format_row() && mysql_bin_log.is_open());
  int error= 0;

  MY_BITMAP *old_read_set= table->read_set;
  MY_BITMAP *old_write_set= table->write_set;

  binlog_prepare_row_images(table);

  /* 
     Pack records into format for transfer. We are allocating more
     memory than needed, but that doesn't matter.
  */
  Row_data_memory memory(table, max_row_length(table, record));
  if (unlikely(!memory.has_memory()))
    return HA_ERR_OUT_OF_MEM;

  uchar *row_data= memory.slot(0);

  DBUG_DUMP("table->read_set", (uchar*) table->read_set->bitmap, (table->s->fields + 7) / 8);
  size_t const len= pack_row(table, table->read_set, row_data, record);

  Rows_log_event* const ev=
    binlog_prepare_pending_rows_event(table, server_id, len, is_trans,
                                      static_cast<Delete_rows_log_event*>(0),
                                      extra_row_info);

  if (unlikely(ev == 0))
    return HA_ERR_OUT_OF_MEM;

  error= ev->add_row_data(row_data, len);

  /* restore read/write set for the rest of execution */
  table->column_bitmaps_set_no_signal(old_read_set,
                                      old_write_set);

  return error;
}

void THD::binlog_prepare_row_images(TABLE *table) 
{
  DBUG_ENTER("THD::binlog_prepare_row_images");
  DBUG_PRINT_BITSET("debug", "table->read_set (before preparing): %s", table->read_set);
  THD *thd= table->in_use;

  if (table->s->primary_key < MAX_KEY &&
      (thd->variables.binlog_row_image < BINLOG_ROW_IMAGE_FULL) &&
      !ha_check_storage_engine_flag(table->s->db_type(), HTON_NO_BINLOG_ROW_OPT))
  {
    DBUG_ASSERT(table->read_set != &table->tmp_set);

    bitmap_clear_all(&table->tmp_set);

    switch(thd->variables.binlog_row_image)
    {
      case BINLOG_ROW_IMAGE_MINIMAL:
        /* MINIMAL: Mark only PK */
        table->mark_columns_used_by_index_no_reset(table->s->primary_key,
                                                   &table->tmp_set);
        break;
      case BINLOG_ROW_IMAGE_NOBLOB:
        bitmap_union(&table->tmp_set, table->read_set);
        for (Field **ptr=table->field ; *ptr ; ptr++)
        {
          Field *field= (*ptr);
          if ((field->type() == MYSQL_TYPE_BLOB) &&
              !(field->flags & PRI_KEY_FLAG))
            bitmap_clear_bit(&table->tmp_set, field->field_index);
        }
        break;
      default:
        DBUG_ASSERT(0); // impossible.
    }

    /* set the temporary read_set */
    table->column_bitmaps_set_no_signal(&table->tmp_set,
                                        table->write_set);
  }

  DBUG_PRINT_BITSET("debug", "table->read_set (after preparing): %s", table->read_set);
  DBUG_VOID_RETURN;
}


int THD::binlog_flush_pending_rows_event(bool stmt_end, bool is_transactional)
{
  DBUG_ENTER("THD::binlog_flush_pending_rows_event");
  /*
    We shall flush the pending event even if we are not in row-based
    mode: it might be the case that we left row-based mode before
    flushing anything (e.g., if we have explicitly locked tables).
   */
  if (!mysql_bin_log.is_open())
    DBUG_RETURN(0);

  /*
    Mark the event as the last event of a statement if the stmt_end
    flag is set.
  */
  int error= 0;
  if (Rows_log_event *pending= binlog_get_pending_rows_event(is_transactional))
  {
    if (stmt_end)
    {
      pending->set_flags(Rows_log_event::STMT_END_F);
      binlog_table_maps= 0;
    }

    error= mysql_bin_log.flush_and_set_pending_rows_event(this, 0,
                                                          is_transactional);
  }

  DBUG_RETURN(error);
}


bool
THD::binlog_row_event_extra_data_eq(const uchar* a,
                                    const uchar* b)
{
  return ((a == b) ||
          ((a != NULL) &&
           (b != NULL) &&
           (a[EXTRA_ROW_INFO_LEN_OFFSET] ==
            b[EXTRA_ROW_INFO_LEN_OFFSET]) &&
           (memcmp(a, b,
                   a[EXTRA_ROW_INFO_LEN_OFFSET]) == 0)));
}

#if !defined(DBUG_OFF) && !defined(_lint)
static const char *
show_query_type(THD::enum_binlog_query_type qtype)
{
  switch (qtype) {
  case THD::ROW_QUERY_TYPE:
    return "ROW";
  case THD::STMT_QUERY_TYPE:
    return "STMT";
  case THD::QUERY_TYPE_COUNT:
  default:
    DBUG_ASSERT(0 <= qtype && qtype < THD::QUERY_TYPE_COUNT);
  }
  static char buf[64];
  sprintf(buf, "UNKNOWN#%d", qtype);
  return buf;
}
#endif

static void reset_binlog_unsafe_suppression()
{
  DBUG_ENTER("reset_binlog_unsafe_suppression");
  unsafe_warning_suppression_is_activated= false;
  limit_unsafe_warning_count= 0;
  limit_unsafe_suppression_start_time= my_getsystime()/10000000;
  DBUG_VOID_RETURN;
}

static void print_unsafe_warning_to_log(int unsafe_type, char* buf,
                                 char* query)
{
  DBUG_ENTER("print_unsafe_warning_in_log");
  sprintf(buf, ER(ER_BINLOG_UNSAFE_STATEMENT),
          ER(LEX::binlog_stmt_unsafe_errcode[unsafe_type]));
  sql_print_warning(ER(ER_MESSAGE_AND_STATEMENT), buf, query);
  DBUG_VOID_RETURN;
}

static void do_unsafe_limit_checkout(char* buf, int unsafe_type, char* query)
{
  ulonglong now;
  DBUG_ENTER("do_unsafe_limit_checkout");
  DBUG_ASSERT(unsafe_type == LEX::BINLOG_STMT_UNSAFE_LIMIT);
  limit_unsafe_warning_count++;
  /*
    INITIALIZING:
    If this is the first time this function is called with log warning
    enabled, the monitoring the unsafe warnings should start.
  */
  if (limit_unsafe_suppression_start_time == 0)
  {
    limit_unsafe_suppression_start_time= my_getsystime()/10000000;
    print_unsafe_warning_to_log(unsafe_type, buf, query);
  }
  else
  {
    if (!unsafe_warning_suppression_is_activated)
      print_unsafe_warning_to_log(unsafe_type, buf, query);

    if (limit_unsafe_warning_count >=
        LIMIT_UNSAFE_WARNING_ACTIVATION_THRESHOLD_COUNT)
    {
      now= my_getsystime()/10000000;
      if (!unsafe_warning_suppression_is_activated)
      {
        /*
          ACTIVATION:
          We got LIMIT_UNSAFE_WARNING_ACTIVATION_THRESHOLD_COUNT warnings in
          less than LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT we activate the
          suppression.
        */
        if ((now-limit_unsafe_suppression_start_time) <=
                       LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT)
        {
          unsafe_warning_suppression_is_activated= true;
          DBUG_PRINT("info",("A warning flood has been detected and the limit \
unsafety warning suppression has been activated."));
        }
        else
        {
          /*
           there is no flooding till now, therefore we restart the monitoring
          */
          limit_unsafe_suppression_start_time= my_getsystime()/10000000;
          limit_unsafe_warning_count= 0;
        }
      }
      else
      {
        /*
          Print the suppression note and the unsafe warning.
        */
        sql_print_information("The following warning was suppressed %d times \
during the last %d seconds in the error log",
                              limit_unsafe_warning_count,
                              (int)
                              (now-limit_unsafe_suppression_start_time));
        print_unsafe_warning_to_log(unsafe_type, buf, query);
        /*
          DEACTIVATION: We got LIMIT_UNSAFE_WARNING_ACTIVATION_THRESHOLD_COUNT
          warnings in more than  LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT, the
          suppression should be deactivated.
        */
        if ((now - limit_unsafe_suppression_start_time) >
            LIMIT_UNSAFE_WARNING_ACTIVATION_TIMEOUT)
        {
          reset_binlog_unsafe_suppression();
          DBUG_PRINT("info",("The limit unsafety warning supression has been \
deactivated"));
        }
      }
      limit_unsafe_warning_count= 0;
    }
  }
  DBUG_VOID_RETURN;
}

void THD::issue_unsafe_warnings()
{
  char buf[MYSQL_ERRMSG_SIZE * 2];
  DBUG_ENTER("issue_unsafe_warnings");
  /*
    Ensure that binlog_unsafe_warning_flags is big enough to hold all
    bits.  This is actually a constant expression.
  */
  DBUG_ASSERT(LEX::BINLOG_STMT_UNSAFE_COUNT <=
              sizeof(binlog_unsafe_warning_flags) * CHAR_BIT);

  uint32 unsafe_type_flags= binlog_unsafe_warning_flags;

  /*
    For each unsafe_type, check if the statement is unsafe in this way
    and issue a warning.
  */
  for (int unsafe_type=0;
       unsafe_type < LEX::BINLOG_STMT_UNSAFE_COUNT;
       unsafe_type++)
  {
    if ((unsafe_type_flags & (1 << unsafe_type)) != 0)
    {
      push_warning_printf(this, Sql_condition::WARN_LEVEL_NOTE,
                          ER_BINLOG_UNSAFE_STATEMENT,
                          ER(ER_BINLOG_UNSAFE_STATEMENT),
                          ER(LEX::binlog_stmt_unsafe_errcode[unsafe_type]));
      if (log_warnings)
      {
        if (unsafe_type == LEX::BINLOG_STMT_UNSAFE_LIMIT)
          do_unsafe_limit_checkout( buf, unsafe_type, query());
        else //cases other than LIMIT unsafety
          print_unsafe_warning_to_log(unsafe_type, buf, query());
      }
    }
  }
  DBUG_VOID_RETURN;
}

int THD::binlog_query(THD::enum_binlog_query_type qtype, char const *query_arg,
                      ulong query_len, bool is_trans, bool direct, 
                      bool suppress_use, int errcode)
{
  DBUG_ENTER("THD::binlog_query");
  DBUG_PRINT("enter", ("qtype: %s  query: '%s'",
                       show_query_type(qtype), query_arg));
  DBUG_ASSERT(query_arg && mysql_bin_log.is_open());

  if (get_binlog_local_stmt_filter() == BINLOG_FILTER_SET)
  {
    /*
      The current statement is to be ignored, and not written to
      the binlog. Do not call issue_unsafe_warnings().
    */
    DBUG_RETURN(0);
  }

  /*
    If we are not in prelocked mode, mysql_unlock_tables() will be
    called after this binlog_query(), so we have to flush the pending
    rows event with the STMT_END_F set to unlock all tables at the
    slave side as well.

    If we are in prelocked mode, the flushing will be done inside the
    top-most close_thread_tables().
  */
  if (this->locked_tables_mode <= LTM_LOCK_TABLES)
    if (int error= binlog_flush_pending_rows_event(TRUE, is_trans))
      DBUG_RETURN(error);

  /*
    Warnings for unsafe statements logged in statement format are
    printed in three places instead of in decide_logging_format().
    This is because the warnings should be printed only if the statement
    is actually logged. When executing decide_logging_format(), we cannot
    know for sure if the statement will be logged:

    1 - sp_head::execute_procedure which prints out warnings for calls to
    stored procedures.

    2 - sp_head::execute_function which prints out warnings for calls
    involving functions.

    3 - THD::binlog_query (here) which prints warning for top level
    statements not covered by the two cases above: i.e., if not insided a
    procedure and a function.
 
    Besides, we should not try to print these warnings if it is not
    possible to write statements to the binary log as it happens when
    the execution is inside a function, or generaly speaking, when
    the variables.option_bits & OPTION_BIN_LOG is false.
  */
  if ((variables.option_bits & OPTION_BIN_LOG) &&
      sp_runtime_ctx == NULL && !binlog_evt_union.do_union)
    issue_unsafe_warnings();

  switch (qtype) {
    /*
      ROW_QUERY_TYPE means that the statement may be logged either in
      row format or in statement format.  If
      current_stmt_binlog_format is row, it means that the
      statement has already been logged in row format and hence shall
      not be logged again.
    */
  case THD::ROW_QUERY_TYPE:
    DBUG_PRINT("debug",
               ("is_current_stmt_binlog_format_row: %d",
                is_current_stmt_binlog_format_row()));
    if (is_current_stmt_binlog_format_row())
      DBUG_RETURN(0);
    /* Fall through */

    /*
      STMT_QUERY_TYPE means that the query must be logged in statement
      format; it cannot be logged in row format.  This is typically
      used by DDL statements.  It is an error to use this query type
      if current_stmt_binlog_format_row is row.

      @todo Currently there are places that call this method with
      STMT_QUERY_TYPE and current_stmt_binlog_format is row.  Fix those
      places and add assert to ensure correct behavior. /Sven
    */
  case THD::STMT_QUERY_TYPE:
    /*
      The MYSQL_LOG::write() function will set the STMT_END_F flag and
      flush the pending rows event if necessary.
    */
    {
      Query_log_event qinfo(this, query_arg, query_len, is_trans, direct,
                            suppress_use, errcode);
      /*
        Binlog table maps will be irrelevant after a Query_log_event
        (they are just removed on the slave side) so after the query
        log event is written to the binary log, we pretend that no
        table maps were written.
       */
      int error= mysql_bin_log.write_event(&qinfo);
      binlog_table_maps= 0;
      DBUG_RETURN(error);
    }
    break;

  case THD::QUERY_TYPE_COUNT:
  default:
    DBUG_ASSERT(0 <= qtype && qtype < QUERY_TYPE_COUNT);
  }
  DBUG_RETURN(0);
}

#endif /* !defined(MYSQL_CLIENT) */

struct st_mysql_storage_engine binlog_storage_engine=
{ MYSQL_HANDLERTON_INTERFACE_VERSION };

mysql_declare_plugin(binlog)
{
  MYSQL_STORAGE_ENGINE_PLUGIN,
  &binlog_storage_engine,
  "binlog",
  "MySQL AB",
  "This is a pseudo storage engine to represent the binlog in a transaction",
  PLUGIN_LICENSE_GPL,
  binlog_init, /* Plugin Init */
  NULL, /* Plugin Deinit */
  0x0100 /* 1.0 */,
  NULL,                       /* status variables                */
  NULL,                       /* system variables                */
  NULL,                       /* config options                  */
  0,  
}
mysql_declare_plugin_end;