sql_prepare.cc

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/* Copyright (c) 2002, 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, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include "my_global.h"                          /* NO_EMBEDDED_ACCESS_CHECKS */
#include "sql_priv.h"
#include "unireg.h"
#include "sql_class.h"                          // set_var.h: THD
#include "set_var.h"
#include "sql_prepare.h"
#include "sql_parse.h" // insert_precheck, update_precheck, delete_precheck
#include "sql_base.h"  // open_normal_and_derived_tables
#include "sql_cache.h"                          // query_cache_*
#include "sql_view.h"                          // create_view_precheck
#include "sql_delete.h"                        // mysql_prepare_delete
#include "sql_select.h" // for JOIN
#include "sql_insert.h" // upgrade_lock_type_for_insert, mysql_prepare_insert
#include "sql_update.h" // mysql_prepare_update
#include "sql_db.h"     // mysql_opt_change_db, mysql_change_db
#include "sql_acl.h"    // *_ACL
#include "sql_cursor.h"
#include "sp_head.h"
#include "sp.h"
#include "sp_cache.h"
#include "sql_handler.h"  // mysql_ha_rm_tables
#include "probes_mysql.h"
#ifdef EMBEDDED_LIBRARY
/* include MYSQL_BIND headers */
#include <mysql.h>
#else
#include <mysql_com.h>
#endif
#include "lock.h"                               // MYSQL_OPEN_FORCE_SHARED_MDL
#include "opt_trace.h"                          // Opt_trace_object
#include "sql_analyse.h"
#include "sql_rewrite.h"
#include "transaction.h"                        // trans_rollback_implicit

#include <algorithm>
using std::max;
using std::min;

class Select_fetch_protocol_binary: public select_send
{
  Protocol_binary protocol;
public:
  Select_fetch_protocol_binary(THD *thd);
  virtual bool send_result_set_metadata(List<Item> &list, uint flags);
  virtual bool send_data(List<Item> &items);
  virtual bool send_eof();
#ifdef EMBEDDED_LIBRARY
  void begin_dataset()
  {
    protocol.begin_dataset();
  }
#endif
};

/****************************************************************************/

class Prepared_statement: public Statement
{
public:
  enum flag_values
  {
    IS_IN_USE= 1,
    IS_SQL_PREPARE= 2
  };

  THD *thd;
  Select_fetch_protocol_binary result;
  Item_param **param_array;
  Server_side_cursor *cursor;
  uint param_count;
  uint last_errno;
  uint flags;
  char last_error[MYSQL_ERRMSG_SIZE];
#ifndef EMBEDDED_LIBRARY
  bool (*set_params)(Prepared_statement *st, uchar *data, uchar *data_end,
                     uchar *read_pos, String *expanded_query);
#else
  bool (*set_params_data)(Prepared_statement *st, String *expanded_query);
#endif
  bool (*set_params_from_vars)(Prepared_statement *stmt,
                               List<LEX_STRING>& varnames,
                               String *expanded_query);
public:
  Prepared_statement(THD *thd_arg);
  virtual ~Prepared_statement();
  void setup_set_params();
  virtual Query_arena::Type type() const;
  virtual void cleanup_stmt();
  bool set_name(LEX_STRING *name);
  inline void close_cursor() { delete cursor; cursor= 0; }
  inline bool is_in_use() { return flags & (uint) IS_IN_USE; }
  inline bool is_sql_prepare() const { return flags & (uint) IS_SQL_PREPARE; }
  void set_sql_prepare() { flags|= (uint) IS_SQL_PREPARE; }
  bool prepare(const char *packet, uint packet_length);
  bool execute_loop(String *expanded_query,
                    bool open_cursor,
                    uchar *packet_arg, uchar *packet_end_arg);
  bool execute_server_runnable(Server_runnable *server_runnable);
  /* Destroy this statement */
  void deallocate();
private:
  MEM_ROOT main_mem_root;
private:
  bool set_db(const char *db, uint db_length);
  bool set_parameters(String *expanded_query,
                      uchar *packet, uchar *packet_end);
  bool execute(String *expanded_query, bool open_cursor);
  bool reprepare();
  bool validate_metadata(Prepared_statement  *copy);
  void swap_prepared_statement(Prepared_statement *copy);
};

class Execute_sql_statement: public Server_runnable
{
public:
  Execute_sql_statement(LEX_STRING sql_text);
  virtual bool execute_server_code(THD *thd);
private:
  LEX_STRING m_sql_text;
};


class Ed_connection;

class Protocol_local :public Protocol
{
public:
  Protocol_local(THD *thd, Ed_connection *ed_connection);
  ~Protocol_local() { free_root(&m_rset_root, MYF(0)); }
protected:
  virtual void prepare_for_resend();
  virtual bool write();
  virtual bool store_null();
  virtual bool store_tiny(longlong from);
  virtual bool store_short(longlong from);
  virtual bool store_long(longlong from);
  virtual bool store_longlong(longlong from, bool unsigned_flag);
  virtual bool store_decimal(const my_decimal *);
  virtual bool store(const char *from, size_t length, const CHARSET_INFO *cs);
  virtual bool store(const char *from, size_t length,
                     const CHARSET_INFO *fromcs, const CHARSET_INFO *tocs);
  virtual bool store(MYSQL_TIME *time, uint precision);
  virtual bool store_date(MYSQL_TIME *time);
  virtual bool store_time(MYSQL_TIME *time, uint precision);
  virtual bool store(float value, uint32 decimals, String *buffer);
  virtual bool store(double value, uint32 decimals, String *buffer);
  virtual bool store(Field *field);

  virtual bool send_result_set_metadata(List<Item> *list, uint flags);
  virtual bool send_out_parameters(List<Item_param> *sp_params);
#ifdef EMBEDDED_LIBRARY
  void remove_last_row();
#endif
  virtual enum enum_protocol_type type() { return PROTOCOL_LOCAL; };

  virtual bool send_ok(uint server_status, uint statement_warn_count,
                       ulonglong affected_rows, ulonglong last_insert_id,
                       const char *message);

  virtual bool send_eof(uint server_status, uint statement_warn_count);
  virtual bool send_error(uint sql_errno, const char *err_msg, const char* sqlstate);
private:
  bool store_string(const char *str, size_t length,
                    const CHARSET_INFO *src_cs, const CHARSET_INFO *dst_cs);

  bool store_column(const void *data, size_t length);
  void opt_add_row_to_rset();
private:
  Ed_connection *m_connection;
  MEM_ROOT m_rset_root;
  List<Ed_row> *m_rset;
  size_t m_column_count;
  Ed_column *m_current_row;
  Ed_column *m_current_column;
};

/******************************************************************************
  Implementation
******************************************************************************/

static inline void rewrite_query_if_needed(THD *thd)
{
  bool general= (opt_log &&
                 !(opt_log_raw || thd->slave_thread));

  if ((thd->sp_runtime_ctx == NULL) &&
      (general || opt_slow_log || opt_bin_log))
    mysql_rewrite_query(thd);
}

static inline void log_execute_line(THD *thd)
{
  /*
    Do not print anything if this is an SQL prepared statement and
    we're inside a stored procedure (also called Dynamic SQL) --
    sub-statements inside stored procedures are not logged into
    the general log.
  */
  if (thd->sp_runtime_ctx != NULL)
    return;

  if (thd->rewritten_query.length())
    logger.general_log_write(thd, COM_STMT_EXECUTE,
                             thd->rewritten_query.c_ptr_safe(),
                             thd->rewritten_query.length());
  else
    logger.general_log_write(thd, COM_STMT_EXECUTE,
                             thd->query(), thd->query_length());
}


inline bool is_param_null(const uchar *pos, ulong param_no)
{
  return pos[param_no/8] & (1 << (param_no & 7));
}

static Prepared_statement *
find_prepared_statement(THD *thd, ulong id)
{
  /*
    To strictly separate namespaces of SQL prepared statements and C API
    prepared statements find() will return 0 if there is a named prepared
    statement with such id.
  */
  Statement *stmt= thd->stmt_map.find(id);

  if (stmt == 0 || stmt->type() != Query_arena::PREPARED_STATEMENT)
    return NULL;

  return (Prepared_statement *) stmt;
}


#ifndef EMBEDDED_LIBRARY
static bool send_prep_stmt(Prepared_statement *stmt, uint columns)
{
  NET *net= &stmt->thd->net;
  uchar buff[12];
  uint tmp;
  int error;
  THD *thd= stmt->thd;
  DBUG_ENTER("send_prep_stmt");

  buff[0]= 0;                                   /* OK packet indicator */
  int4store(buff+1, stmt->id);
  int2store(buff+5, columns);
  int2store(buff+7, stmt->param_count);
  buff[9]= 0;                                   // Guard against a 4.1 client
  tmp= min(stmt->thd->get_stmt_da()->current_statement_warn_count(), 65535UL);
  int2store(buff+10, tmp);

  /*
    Send types and names of placeholders to the client
    XXX: fix this nasty upcast from List<Item_param> to List<Item>
  */
  error= my_net_write(net, buff, sizeof(buff));
  if (stmt->param_count && ! error)
  {
    error= thd->protocol_text.send_result_set_metadata((List<Item> *)
                                          &stmt->lex->param_list,
                                          Protocol::SEND_EOF);
  }

  if (!error)
    /* Flag that a response has already been sent */
    thd->get_stmt_da()->disable_status();

  DBUG_RETURN(error);
}
#else
static bool send_prep_stmt(Prepared_statement *stmt,
                           uint columns __attribute__((unused)))
{
  THD *thd= stmt->thd;

  thd->client_stmt_id= stmt->id;
  thd->client_param_count= stmt->param_count;
  thd->clear_error();
  thd->get_stmt_da()->disable_status();

  return 0;
}
#endif 
#ifndef EMBEDDED_LIBRARY

static ulong get_param_length(uchar **packet, ulong len)
{
  reg1 uchar *pos= *packet;
  if (len < 1)
    return 0;
  if (*pos < 251)
  {
    (*packet)++;
    return (ulong) *pos;
  }
  if (len < 3)
    return 0;
  if (*pos == 252)
  {
    (*packet)+=3;
    return (ulong) uint2korr(pos+1);
  }
  if (len < 4)
    return 0;
  if (*pos == 253)
  {
    (*packet)+=4;
    return (ulong) uint3korr(pos+1);
  }
  if (len < 5)
    return 0;
  (*packet)+=9; // Must be 254 when here
  /*
    In our client-server protocol all numbers bigger than 2^24
    stored as 8 bytes with uint8korr. Here we always know that
    parameter length is less than 2^4 so don't look at the second
    4 bytes. But still we need to obey the protocol hence 9 in the
    assignment above.
  */
  return (ulong) uint4korr(pos+1);
}
#else
#define get_param_length(packet, len) len
#endif 
static void set_param_tiny(Item_param *param, uchar **pos, ulong len)
{
#ifndef EMBEDDED_LIBRARY
  if (len < 1)
    return;
#endif
  int8 value= (int8) **pos;
  param->set_int(param->unsigned_flag ? (longlong) ((uint8) value) :
                                        (longlong) value, 4);
  *pos+= 1;
}

static void set_param_short(Item_param *param, uchar **pos, ulong len)
{
  int16 value;
#ifndef EMBEDDED_LIBRARY
  if (len < 2)
    return;
  value= sint2korr(*pos);
#else
  shortget(value, *pos);
#endif
  param->set_int(param->unsigned_flag ? (longlong) ((uint16) value) :
                                        (longlong) value, 6);
  *pos+= 2;
}

static void set_param_int32(Item_param *param, uchar **pos, ulong len)
{
  int32 value;
#ifndef EMBEDDED_LIBRARY
  if (len < 4)
    return;
  value= sint4korr(*pos);
#else
  longget(value, *pos);
#endif
  param->set_int(param->unsigned_flag ? (longlong) ((uint32) value) :
                                        (longlong) value, 11);
  *pos+= 4;
}

static void set_param_int64(Item_param *param, uchar **pos, ulong len)
{
  longlong value;
#ifndef EMBEDDED_LIBRARY
  if (len < 8)
    return;
  value= (longlong) sint8korr(*pos);
#else
  longlongget(value, *pos);
#endif
  param->set_int(value, 21);
  *pos+= 8;
}

static void set_param_float(Item_param *param, uchar **pos, ulong len)
{
  float data;
#ifndef EMBEDDED_LIBRARY
  if (len < 4)
    return;
  float4get(data,*pos);
#else
  floatget(data, *pos);
#endif
  param->set_double((double) data);
  *pos+= 4;
}

static void set_param_double(Item_param *param, uchar **pos, ulong len)
{
  double data;
#ifndef EMBEDDED_LIBRARY
  if (len < 8)
    return;
  float8get(data,*pos);
#else
  doubleget(data, *pos);
#endif
  param->set_double((double) data);
  *pos+= 8;
}

static void set_param_decimal(Item_param *param, uchar **pos, ulong len)
{
  ulong length= get_param_length(pos, len);
  param->set_decimal((char*)*pos, length);
  *pos+= length;
}

#ifndef EMBEDDED_LIBRARY

/*
  Read date/time/datetime parameter values from network (binary
  protocol). See writing counterparts of these functions in
  libmysql.c (store_param_{time,date,datetime}).
*/

static void set_param_time(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME tm;
  ulong length= get_param_length(pos, len);

  if (length >= 8)
  {
    uchar *to= *pos;
    uint day;

    tm.neg= (bool) to[0];
    day= (uint) sint4korr(to+1);
    tm.hour=   (uint) to[5] + day * 24;
    tm.minute= (uint) to[6];
    tm.second= (uint) to[7];
    tm.second_part= (length > 8) ? (ulong) sint4korr(to+8) : 0;
    if (tm.hour > 838)
    {
      /* TODO: add warning 'Data truncated' here */
      tm.hour= 838;
      tm.minute= 59;
      tm.second= 59;
    }
    tm.day= tm.year= tm.month= 0;
  }
  else
    set_zero_time(&tm, MYSQL_TIMESTAMP_TIME);
  param->set_time(&tm, MYSQL_TIMESTAMP_TIME,
                  MAX_TIME_FULL_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
  *pos+= length;
}

static void set_param_datetime(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME tm;
  ulong length= get_param_length(pos, len);

  if (length >= 4)
  {
    uchar *to= *pos;

    tm.neg=    0;
    tm.year=   (uint) sint2korr(to);
    tm.month=  (uint) to[2];
    tm.day=    (uint) to[3];
    if (length > 4)
    {
      tm.hour=   (uint) to[4];
      tm.minute= (uint) to[5];
      tm.second= (uint) to[6];
    }
    else
      tm.hour= tm.minute= tm.second= 0;

    tm.second_part= (length > 7) ? (ulong) sint4korr(to+7) : 0;
  }
  else
    set_zero_time(&tm, MYSQL_TIMESTAMP_DATETIME);
  param->set_time(&tm, MYSQL_TIMESTAMP_DATETIME,
                  MAX_DATETIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
  *pos+= length;
}


static void set_param_date(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME tm;
  ulong length= get_param_length(pos, len);

  if (length >= 4)
  {
    uchar *to= *pos;

    tm.year=  (uint) sint2korr(to);
    tm.month=  (uint) to[2];
    tm.day= (uint) to[3];

    tm.hour= tm.minute= tm.second= 0;
    tm.second_part= 0;
    tm.neg= 0;
  }
  else
    set_zero_time(&tm, MYSQL_TIMESTAMP_DATE);
  param->set_time(&tm, MYSQL_TIMESTAMP_DATE,
                  MAX_DATE_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
  *pos+= length;
}

#else
void set_param_time(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME tm= *((MYSQL_TIME*)*pos);
  tm.hour+= tm.day * 24;
  tm.day= tm.year= tm.month= 0;
  if (tm.hour > 838)
  {
    /* TODO: add warning 'Data truncated' here */
    tm.hour= 838;
    tm.minute= 59;
    tm.second= 59;
  }
  param->set_time(&tm, MYSQL_TIMESTAMP_TIME,
                  MAX_TIME_FULL_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);

}

void set_param_datetime(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME tm= *((MYSQL_TIME*)*pos);
  tm.neg= 0;

  param->set_time(&tm, MYSQL_TIMESTAMP_DATETIME,
                  MAX_DATETIME_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
}

void set_param_date(Item_param *param, uchar **pos, ulong len)
{
  MYSQL_TIME *to= (MYSQL_TIME*)*pos;

  param->set_time(to, MYSQL_TIMESTAMP_DATE,
                  MAX_DATE_WIDTH * MY_CHARSET_BIN_MB_MAXLEN);
}
#endif 
static void set_param_str(Item_param *param, uchar **pos, ulong len)
{
  ulong length= get_param_length(pos, len);
  if (length > len)
    length= len;
  param->set_str((const char *)*pos, length);
  *pos+= length;
}


#undef get_param_length

static void setup_one_conversion_function(THD *thd, Item_param *param,
                                          uchar param_type)
{
  switch (param_type) {
  case MYSQL_TYPE_TINY:
    param->set_param_func= set_param_tiny;
    param->item_type= Item::INT_ITEM;
    param->item_result_type= INT_RESULT;
    break;
  case MYSQL_TYPE_SHORT:
    param->set_param_func= set_param_short;
    param->item_type= Item::INT_ITEM;
    param->item_result_type= INT_RESULT;
    break;
  case MYSQL_TYPE_LONG:
    param->set_param_func= set_param_int32;
    param->item_type= Item::INT_ITEM;
    param->item_result_type= INT_RESULT;
    break;
  case MYSQL_TYPE_LONGLONG:
    param->set_param_func= set_param_int64;
    param->item_type= Item::INT_ITEM;
    param->item_result_type= INT_RESULT;
    break;
  case MYSQL_TYPE_FLOAT:
    param->set_param_func= set_param_float;
    param->item_type= Item::REAL_ITEM;
    param->item_result_type= REAL_RESULT;
    break;
  case MYSQL_TYPE_DOUBLE:
    param->set_param_func= set_param_double;
    param->item_type= Item::REAL_ITEM;
    param->item_result_type= REAL_RESULT;
    break;
  case MYSQL_TYPE_DECIMAL:
  case MYSQL_TYPE_NEWDECIMAL:
    param->set_param_func= set_param_decimal;
    param->item_type= Item::DECIMAL_ITEM;
    param->item_result_type= DECIMAL_RESULT;
    break;
  case MYSQL_TYPE_TIME:
    param->set_param_func= set_param_time;
    param->item_type= Item::STRING_ITEM;
    param->item_result_type= STRING_RESULT;
    break;
  case MYSQL_TYPE_DATE:
    param->set_param_func= set_param_date;
    param->item_type= Item::STRING_ITEM;
    param->item_result_type= STRING_RESULT;
    break;
  case MYSQL_TYPE_DATETIME:
  case MYSQL_TYPE_TIMESTAMP:
    param->set_param_func= set_param_datetime;
    param->item_type= Item::STRING_ITEM;
    param->item_result_type= STRING_RESULT;
    break;
  case MYSQL_TYPE_TINY_BLOB:
  case MYSQL_TYPE_MEDIUM_BLOB:
  case MYSQL_TYPE_LONG_BLOB:
  case MYSQL_TYPE_BLOB:
    param->set_param_func= set_param_str;
    param->value.cs_info.character_set_of_placeholder= &my_charset_bin;
    param->value.cs_info.character_set_client=
      thd->variables.character_set_client;
    DBUG_ASSERT(thd->variables.character_set_client);
    param->value.cs_info.final_character_set_of_str_value= &my_charset_bin;
    param->item_type= Item::STRING_ITEM;
    param->item_result_type= STRING_RESULT;
    break;
  default:
    /*
      The client library ensures that we won't get any other typecodes
      except typecodes above and typecodes for string types. Marking
      label as 'default' lets us to handle malformed packets as well.
    */
    {
      const CHARSET_INFO *fromcs= thd->variables.character_set_client;
      const CHARSET_INFO *tocs= thd->variables.collation_connection;
      uint32 dummy_offset;

      param->value.cs_info.character_set_of_placeholder= fromcs;
      param->value.cs_info.character_set_client= fromcs;

      /*
        Setup source and destination character sets so that they
        are different only if conversion is necessary: this will
        make later checks easier.
      */
      param->value.cs_info.final_character_set_of_str_value=
        String::needs_conversion(0, fromcs, tocs, &dummy_offset) ?
        tocs : fromcs;
      param->set_param_func= set_param_str;
      /*
        Exact value of max_length is not known unless data is converted to
        charset of connection, so we have to set it later.
      */
      param->item_type= Item::STRING_ITEM;
      param->item_result_type= STRING_RESULT;
    }
  }
  param->param_type= (enum enum_field_types) param_type;
}

#ifndef EMBEDDED_LIBRARY

inline bool is_param_long_data_type(Item_param *param)
{
  return ((param->param_type >= MYSQL_TYPE_TINY_BLOB) &&
          (param->param_type <= MYSQL_TYPE_STRING));
}


static bool insert_params_with_log(Prepared_statement *stmt, uchar *null_array,
                                   uchar *read_pos, uchar *data_end,
                                   String *query)
{
  THD  *thd= stmt->thd;
  Item_param **begin= stmt->param_array;
  Item_param **end= begin + stmt->param_count;
  uint32 length= 0;
  String str;
  const String *res;
  DBUG_ENTER("insert_params_with_log");

  if (query->copy(stmt->query(), stmt->query_length(), default_charset_info))
    DBUG_RETURN(1);

  for (Item_param **it= begin; it < end; ++it)
  {
    Item_param *param= *it;
    if (param->state != Item_param::LONG_DATA_VALUE)
    {
      if (is_param_null(null_array, (uint) (it - begin)))
        param->set_null();
      else
      {
        if (read_pos >= data_end)
          DBUG_RETURN(1);
        param->set_param_func(param, &read_pos, (uint) (data_end - read_pos));
        if (param->state == Item_param::NO_VALUE)
          DBUG_RETURN(1);

        if (param->limit_clause_param && param->item_type != Item::INT_ITEM)
        {
          param->set_int(param->val_int(), MY_INT64_NUM_DECIMAL_DIGITS);
          param->item_type= Item::INT_ITEM;
          if (!param->unsigned_flag && param->value.integer < 0)
            DBUG_RETURN(1);
        }
      }
    }
    /*
      A long data stream was supplied for this parameter marker.
      This was done after prepare, prior to providing a placeholder
      type (the types are supplied at execute). Check that the
      supplied type of placeholder can accept a data stream.
    */
    else if (! is_param_long_data_type(param))
      DBUG_RETURN(1);
    res= param->query_val_str(thd, &str);
    if (param->convert_str_value(thd))
      DBUG_RETURN(1);                           /* out of memory */

    if (query->replace(param->pos_in_query+length, 1, *res))
      DBUG_RETURN(1);

    length+= res->length()-1;
  }
  DBUG_RETURN(0);
}


static bool insert_params(Prepared_statement *stmt, uchar *null_array,
                          uchar *read_pos, uchar *data_end,
                          String *expanded_query)
{
  Item_param **begin= stmt->param_array;
  Item_param **end= begin + stmt->param_count;

  DBUG_ENTER("insert_params");

  for (Item_param **it= begin; it < end; ++it)
  {
    Item_param *param= *it;
    if (param->state != Item_param::LONG_DATA_VALUE)
    {
      if (is_param_null(null_array, (uint) (it - begin)))
        param->set_null();
      else
      {
        if (read_pos >= data_end)
          DBUG_RETURN(1);
        param->set_param_func(param, &read_pos, (uint) (data_end - read_pos));
        if (param->state == Item_param::NO_VALUE)
          DBUG_RETURN(1);
      }
    }
    /*
      A long data stream was supplied for this parameter marker.
      This was done after prepare, prior to providing a placeholder
      type (the types are supplied at execute). Check that the
      supplied type of placeholder can accept a data stream.
    */
    else if (! is_param_long_data_type(param))
      DBUG_RETURN(1);
    if (param->convert_str_value(stmt->thd))
      DBUG_RETURN(1);                           /* out of memory */
  }
  DBUG_RETURN(0);
}


static bool setup_conversion_functions(Prepared_statement *stmt,
                                       uchar **data, uchar *data_end)
{
  /* skip null bits */
  uchar *read_pos= *data + (stmt->param_count+7) / 8;

  DBUG_ENTER("setup_conversion_functions");

  if (read_pos >= data_end)
    DBUG_RETURN(1);

  if (*read_pos++) //types supplied / first execute
  {
    /*
      First execute or types altered by the client, setup the
      conversion routines for all parameters (one time)
    */
    Item_param **it= stmt->param_array;
    Item_param **end= it + stmt->param_count;
    THD *thd= stmt->thd;
    for (; it < end; ++it)
    {
      ushort typecode;
      const uint signed_bit= 1 << 15;

      if (read_pos >= data_end)
        DBUG_RETURN(1);

      typecode= sint2korr(read_pos);
      read_pos+= 2;
      (**it).unsigned_flag= test(typecode & signed_bit);
      setup_one_conversion_function(thd, *it, (uchar) (typecode & ~signed_bit));
    }
  }
  *data= read_pos;
  DBUG_RETURN(0);
}

#else

static bool emb_insert_params(Prepared_statement *stmt, String *expanded_query)
{
  THD *thd= stmt->thd;
  Item_param **it= stmt->param_array;
  Item_param **end= it + stmt->param_count;
  MYSQL_BIND *client_param= stmt->thd->client_params;

  DBUG_ENTER("emb_insert_params");

  for (; it < end; ++it, ++client_param)
  {
    Item_param *param= *it;
    setup_one_conversion_function(thd, param, client_param->buffer_type);
    if (param->state != Item_param::LONG_DATA_VALUE)
    {
      if (*client_param->is_null)
        param->set_null();
      else
      {
        uchar *buff= (uchar*) client_param->buffer;
        param->unsigned_flag= client_param->is_unsigned;
        param->set_param_func(param, &buff,
                              client_param->length ?
                              *client_param->length :
                              client_param->buffer_length);
        if (param->state == Item_param::NO_VALUE)
          DBUG_RETURN(1);
      }
    }
    if (param->convert_str_value(thd))
      DBUG_RETURN(1);                           /* out of memory */
  }
  DBUG_RETURN(0);
}


static bool emb_insert_params_with_log(Prepared_statement *stmt,
                                       String *query)
{
  THD *thd= stmt->thd;
  Item_param **it= stmt->param_array;
  Item_param **end= it + stmt->param_count;
  MYSQL_BIND *client_param= thd->client_params;

  String str;
  const String *res;
  uint32 length= 0;

  DBUG_ENTER("emb_insert_params_with_log");

  if (query->copy(stmt->query(), stmt->query_length(), default_charset_info))
    DBUG_RETURN(1);

  for (; it < end; ++it, ++client_param)
  {
    Item_param *param= *it;
    setup_one_conversion_function(thd, param, client_param->buffer_type);
    if (param->state != Item_param::LONG_DATA_VALUE)
    {
      if (*client_param->is_null)
        param->set_null();
      else
      {
        uchar *buff= (uchar*)client_param->buffer;
        param->unsigned_flag= client_param->is_unsigned;
        param->set_param_func(param, &buff,
                              client_param->length ?
                              *client_param->length :
                              client_param->buffer_length);
        if (param->state == Item_param::NO_VALUE)
          DBUG_RETURN(1);
      }
    }
    res= param->query_val_str(thd, &str);
    if (param->convert_str_value(thd))
      DBUG_RETURN(1);                           /* out of memory */

    if (query->replace(param->pos_in_query+length, 1, *res))
      DBUG_RETURN(1);

    length+= res->length()-1;
  }
  DBUG_RETURN(0);
}

#endif 
static void
swap_parameter_array(Item_param **param_array_dst,
                     Item_param **param_array_src,
                     uint param_count)
{
  Item_param **dst= param_array_dst;
  Item_param **src= param_array_src;
  Item_param **end= param_array_dst + param_count;

  for (; dst < end; ++src, ++dst)
    (*dst)->set_param_type_and_swap_value(*src);
}


static bool insert_params_from_vars(Prepared_statement *stmt,
                                    List<LEX_STRING>& varnames,
                                    String *query __attribute__((unused)))
{
  Item_param **begin= stmt->param_array;
  Item_param **end= begin + stmt->param_count;
  user_var_entry *entry;
  LEX_STRING *varname;
  List_iterator<LEX_STRING> var_it(varnames);
  DBUG_ENTER("insert_params_from_vars");

  for (Item_param **it= begin; it < end; ++it)
  {
    Item_param *param= *it;
    varname= var_it++;
    entry= (user_var_entry*)my_hash_search(&stmt->thd->user_vars,
                                           (uchar*) varname->str,
                                           varname->length);
    if (param->set_from_user_var(stmt->thd, entry) ||
        param->convert_str_value(stmt->thd))
      DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}


static bool insert_params_from_vars_with_log(Prepared_statement *stmt,
                                             List<LEX_STRING>& varnames,
                                             String *query)
{
  Item_param **begin= stmt->param_array;
  Item_param **end= begin + stmt->param_count;
  user_var_entry *entry;
  LEX_STRING *varname;
  List_iterator<LEX_STRING> var_it(varnames);
  String buf;
  const String *val;
  uint32 length= 0;
  THD *thd= stmt->thd;

  DBUG_ENTER("insert_params_from_vars_with_log");

  if (query->copy(stmt->query(), stmt->query_length(), default_charset_info))
    DBUG_RETURN(1);

  for (Item_param **it= begin; it < end; ++it)
  {
    Item_param *param= *it;
    varname= var_it++;

    entry= (user_var_entry *) my_hash_search(&thd->user_vars, (uchar*)
                                             varname->str, varname->length);
    /*
      We have to call the setup_one_conversion_function() here to set
      the parameter's members that might be needed further
      (e.g. value.cs_info.character_set_client is used in the query_val_str()).
    */
    setup_one_conversion_function(thd, param, param->param_type);
    if (param->set_from_user_var(thd, entry))
      DBUG_RETURN(1);
    val= param->query_val_str(thd, &buf);

    if (param->convert_str_value(thd))
      DBUG_RETURN(1);                           /* out of memory */

    if (query->replace(param->pos_in_query+length, 1, *val))
      DBUG_RETURN(1);
    length+= val->length()-1;
  }
  DBUG_RETURN(0);
}

static bool mysql_test_insert(Prepared_statement *stmt,
                              TABLE_LIST *table_list,
                              List<Item> &fields,
                              List<List_item> &values_list,
                              List<Item> &update_fields,
                              List<Item> &update_values,
                              enum_duplicates duplic)
{
  THD *thd= stmt->thd;
  List_iterator_fast<List_item> its(values_list);
  List_item *values;
  DBUG_ENTER("mysql_test_insert");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  /*
    Since INSERT DELAYED doesn't support temporary tables, we could
    not pre-open temporary tables for SQLCOM_INSERT / SQLCOM_REPLACE.
    Open them here instead.
  */
  if (table_list->lock_type != TL_WRITE_DELAYED)
  {
    if (open_temporary_tables(thd, table_list))
      goto error;
  }

  if (insert_precheck(thd, table_list))
    goto error;

  /*
    open temporary memory pool for temporary data allocated by derived
    tables & preparation procedure
    Note that this is done without locks (should not be needed as we will not
    access any data here)
    If we would use locks, then we have to ensure we are not using
    TL_WRITE_DELAYED as having two such locks can cause table corruption.
  */
  if (open_normal_and_derived_tables(thd, table_list,
                                     MYSQL_OPEN_FORCE_SHARED_MDL))
    goto error;

  if ((values= its++))
  {
    uint value_count;
    ulong counter= 0;
    Item *unused_conds= 0;

    if (table_list->table)
    {
      // don't allocate insert_values
      table_list->table->insert_values=(uchar *)1;
    }

    if (mysql_prepare_insert(thd, table_list, table_list->table,
                             fields, values, update_fields, update_values,
                             duplic, &unused_conds, FALSE, FALSE, FALSE))
      goto error;

    value_count= values->elements;
    its.rewind();

    if (table_list->lock_type == TL_WRITE_DELAYED &&
        !(table_list->table->file->ha_table_flags() & HA_CAN_INSERT_DELAYED))
    {
      my_error(ER_DELAYED_NOT_SUPPORTED, MYF(0), (table_list->view ?
                                                  table_list->view_name.str :
                                                  table_list->table_name));
      goto error;
    }
    while ((values= its++))
    {
      counter++;
      if (values->elements != value_count)
      {
        my_error(ER_WRONG_VALUE_COUNT_ON_ROW, MYF(0), counter);
        goto error;
      }
      if (setup_fields(thd, Ref_ptr_array(), *values, MARK_COLUMNS_NONE, 0, 0))
        goto error;
    }
  }
  DBUG_RETURN(FALSE);

error:
  /* insert_values is cleared in open_table */
  DBUG_RETURN(TRUE);
}


static int mysql_test_update(Prepared_statement *stmt,
                              TABLE_LIST *table_list)
{
  int res;
  THD *thd= stmt->thd;
  SELECT_LEX *select= &stmt->lex->select_lex;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  uint          want_privilege;
#endif
  DBUG_ENTER("mysql_test_update");

  if (update_precheck(thd, table_list) ||
      open_normal_and_derived_tables(thd, table_list,
                                     MYSQL_OPEN_FORCE_SHARED_MDL))
    goto error;

  if (table_list->multitable_view)
  {
    DBUG_ASSERT(table_list->view != 0);
    DBUG_PRINT("info", ("Switch to multi-update"));
    /* convert to multiupdate */
    DBUG_RETURN(2);
  }

  if (!table_list->updatable)
  {
    my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias, "UPDATE");
    goto error;
  }

#ifndef NO_EMBEDDED_ACCESS_CHECKS
  /* Force privilege re-checking for views after they have been opened. */
  want_privilege= (table_list->view ? UPDATE_ACL :
                   table_list->grant.want_privilege);
#endif

  if (mysql_prepare_update(thd, table_list, &select->where,
                           select->order_list.elements,
                           select->order_list.first))
    goto error;

#ifndef NO_EMBEDDED_ACCESS_CHECKS
  table_list->grant.want_privilege= want_privilege;
  table_list->table->grant.want_privilege= want_privilege;
  table_list->register_want_access(want_privilege);
#endif
  thd->lex->select_lex.no_wrap_view_item= TRUE;
  res= setup_fields(thd, Ref_ptr_array(),
                    select->item_list, MARK_COLUMNS_READ, 0, 0);
  thd->lex->select_lex.no_wrap_view_item= FALSE;
  if (res)
    goto error;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  /* Check values */
  table_list->grant.want_privilege=
  table_list->table->grant.want_privilege=
    (SELECT_ACL & ~table_list->table->grant.privilege);
  table_list->register_want_access(SELECT_ACL);
#endif
  if (setup_fields(thd, Ref_ptr_array(),
                   stmt->lex->value_list, MARK_COLUMNS_NONE, 0, 0))
    goto error;
  /* TODO: here we should send types of placeholders to the client. */
  DBUG_RETURN(0);
error:
  DBUG_RETURN(1);
}


static bool mysql_test_delete(Prepared_statement *stmt,
                              TABLE_LIST *table_list)
{
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;
  DBUG_ENTER("mysql_test_delete");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  if (delete_precheck(thd, table_list) ||
      open_normal_and_derived_tables(thd, table_list,
                                     MYSQL_OPEN_FORCE_SHARED_MDL))
    goto error;

  if (!table_list->table)
  {
    my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0),
             table_list->view_db.str, table_list->view_name.str);
    goto error;
  }

  DBUG_RETURN(mysql_prepare_delete(thd, table_list, &lex->select_lex.where));
error:
  DBUG_RETURN(TRUE);
}


static int mysql_test_select(Prepared_statement *stmt,
                             TABLE_LIST *tables)
{
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;
  SELECT_LEX_UNIT *unit= &lex->unit;
  DBUG_ENTER("mysql_test_select");

  lex->select_lex.context.resolve_in_select_list= TRUE;

  if (select_precheck(thd, lex, tables, lex->select_lex.table_list.first))
    goto error;

  if (!lex->result && !(lex->result= new (stmt->mem_root) select_send))
  {
    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 
             static_cast<int>(sizeof(select_send)));
    goto error;
  }

  if (open_normal_and_derived_tables(thd, tables, MYSQL_OPEN_FORCE_SHARED_MDL))
    goto error;

  thd->lex->used_tables= 0;                        // Updated by setup_fields

  /*
    JOIN::prepare calls
    It is not SELECT COMMAND for sure, so setup_tables will be called as
    usual, and we pass 0 as setup_tables_done_option
  */
  if (unit->prepare(thd, 0, 0))
    goto error;
  if (!lex->describe && !stmt->is_sql_prepare())
  {
    select_result *result= lex->result;
    select_result *analyse_result= NULL;
    if (lex->proc_analyse)
    {
      /*
        We need proper output recordset metadata for SELECT ... PROCEDURE ANALUSE()
      */
      if ((result= analyse_result=
             new select_analyse(result, lex->proc_analyse)) == NULL)
        goto error; // OOM
    }

    /*
      We can use "result" as it should've been prepared in
      unit->prepare call above.
    */
    bool rc= (send_prep_stmt(stmt, result->field_count(unit->types)) ||
              result->send_result_set_metadata(unit->types,
                                               Protocol::SEND_EOF) ||
              thd->protocol->flush());
    delete analyse_result;
    if (rc)
      goto error;
    DBUG_RETURN(2);
  }
  DBUG_RETURN(0);
error:
  DBUG_RETURN(1);
}


static bool mysql_test_do_fields(Prepared_statement *stmt,
                                TABLE_LIST *tables,
                                List<Item> *values)
{
  THD *thd= stmt->thd;

  DBUG_ENTER("mysql_test_do_fields");
  DBUG_ASSERT(stmt->is_stmt_prepare());
  if (tables && check_table_access(thd, SELECT_ACL, tables, FALSE,
                                   UINT_MAX, FALSE))
    DBUG_RETURN(TRUE);

  if (open_normal_and_derived_tables(thd, tables, MYSQL_OPEN_FORCE_SHARED_MDL))
    DBUG_RETURN(TRUE);
  DBUG_RETURN(setup_fields(thd, Ref_ptr_array(),
                           *values, MARK_COLUMNS_NONE, 0, 0));
}


static bool mysql_test_set_fields(Prepared_statement *stmt,
                                  TABLE_LIST *tables,
                                  List<set_var_base> *var_list)
{
  List_iterator_fast<set_var_base> it(*var_list);
  THD *thd= stmt->thd;
  set_var_base *var;
  DBUG_ENTER("mysql_test_set_fields");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  if ((tables && check_table_access(thd, SELECT_ACL, tables, FALSE,
                                    UINT_MAX, FALSE)) ||
      open_normal_and_derived_tables(thd, tables, MYSQL_OPEN_FORCE_SHARED_MDL))
    goto error;

  while ((var= it++))
  {
    if (var->light_check(thd))
      goto error;
  }
  DBUG_RETURN(FALSE);
error:
  DBUG_RETURN(TRUE);
}


static bool mysql_test_call_fields(Prepared_statement *stmt,
                                   TABLE_LIST *tables,
                                   List<Item> *value_list)
{
  List_iterator<Item> it(*value_list);
  THD *thd= stmt->thd;
  Item *item;
  DBUG_ENTER("mysql_test_call_fields");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  if ((tables && check_table_access(thd, SELECT_ACL, tables, FALSE,
                                    UINT_MAX, FALSE)) ||
      open_normal_and_derived_tables(thd, tables, MYSQL_OPEN_FORCE_SHARED_MDL))
    goto err;

  while ((item= it++))
  {
    if ((!item->fixed && item->fix_fields(thd, it.ref())) ||
        item->check_cols(1))
      goto err;
  }
  DBUG_RETURN(FALSE);
err:
  DBUG_RETURN(TRUE);
}


static bool select_like_stmt_test(Prepared_statement *stmt,
                                  int (*specific_prepare)(THD *thd),
                                  ulong setup_tables_done_option)
{
  DBUG_ENTER("select_like_stmt_test");
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;

  lex->select_lex.context.resolve_in_select_list= TRUE;

  if (specific_prepare && (*specific_prepare)(thd))
    DBUG_RETURN(TRUE);

  thd->lex->used_tables= 0;                        // Updated by setup_fields

  /* Calls JOIN::prepare */
  DBUG_RETURN(lex->unit.prepare(thd, 0, setup_tables_done_option));
}

static bool
select_like_stmt_test_with_open(Prepared_statement *stmt,
                                TABLE_LIST *tables,
                                int (*specific_prepare)(THD *thd),
                                ulong setup_tables_done_option)
{
  DBUG_ENTER("select_like_stmt_test_with_open");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  /*
    We should not call LEX::unit.cleanup() after this
    open_normal_and_derived_tables() call because we don't allow
    prepared EXPLAIN yet so derived tables will clean up after
    themself.
  */
  if (open_normal_and_derived_tables(stmt->thd, tables,
                                     MYSQL_OPEN_FORCE_SHARED_MDL))
    DBUG_RETURN(TRUE);

  DBUG_RETURN(select_like_stmt_test(stmt, specific_prepare,
                                    setup_tables_done_option));
}


static bool mysql_test_create_table(Prepared_statement *stmt)
{
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;
  SELECT_LEX *select_lex= &lex->select_lex;
  bool res= FALSE;
  bool link_to_local;
  TABLE_LIST *create_table= lex->query_tables;
  TABLE_LIST *tables= lex->create_last_non_select_table->next_global;
  DBUG_ENTER("mysql_test_create_table");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  if (create_table_precheck(thd, tables, create_table))
    DBUG_RETURN(TRUE);

  if (select_lex->item_list.elements)
  {
    /* Base table and temporary table are not in the same name space. */
    if (!(lex->create_info.options & HA_LEX_CREATE_TMP_TABLE))
      create_table->open_type= OT_BASE_ONLY;

    if (open_normal_and_derived_tables(stmt->thd, lex->query_tables,
                                       MYSQL_OPEN_FORCE_SHARED_MDL))
      DBUG_RETURN(TRUE);

    select_lex->context.resolve_in_select_list= TRUE;

    lex->unlink_first_table(&link_to_local);

    res= select_like_stmt_test(stmt, 0, 0);

    lex->link_first_table_back(create_table, link_to_local);
  }
  else
  {
    /*
      Check that the source table exist, and also record
      its metadata version. Even though not strictly necessary,
      we validate metadata of all CREATE TABLE statements,
      which keeps metadata validation code simple.
    */
    if (open_normal_and_derived_tables(stmt->thd, lex->query_tables,
                                       MYSQL_OPEN_FORCE_SHARED_MDL))
      DBUG_RETURN(TRUE);
  }

  DBUG_RETURN(res);
}


static bool mysql_test_create_view(Prepared_statement *stmt)
{
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;
  bool res= TRUE;
  /* Skip first table, which is the view we are creating */
  bool link_to_local;
  TABLE_LIST *view= lex->unlink_first_table(&link_to_local);
  TABLE_LIST *tables= lex->query_tables;
  DBUG_ENTER("mysql_test_create_view");
  DBUG_ASSERT(stmt->is_stmt_prepare());

  if (create_view_precheck(thd, tables, view, lex->create_view_mode))
    goto err;

  /*
    Since we can't pre-open temporary tables for SQLCOM_CREATE_VIEW,
    (see mysql_create_view) we have to do it here instead.
  */
  if (open_temporary_tables(thd, tables))
    goto err;

  if (open_normal_and_derived_tables(thd, tables, MYSQL_OPEN_FORCE_SHARED_MDL))
    goto err;

  lex->context_analysis_only|=  CONTEXT_ANALYSIS_ONLY_VIEW;
  res= select_like_stmt_test(stmt, 0, 0);

err:
  /* put view back for PS rexecuting */
  lex->link_first_table_back(view, link_to_local);
  DBUG_RETURN(res);
}


/*
  Validate and prepare for execution a multi update statement.

  @param stmt               prepared statement
  @param tables             list of tables used in this query
  @param converted          converted to multi-update from usual update

  @retval
    FALSE             success
  @retval
    TRUE              error, error message is set in THD
*/

static bool mysql_test_multiupdate(Prepared_statement *stmt,
                                  TABLE_LIST *tables,
                                  bool converted)
{
  /* if we switched from normal update, rights are checked */
  if (!converted && multi_update_precheck(stmt->thd, tables))
    return TRUE;

  return select_like_stmt_test(stmt, &mysql_multi_update_prepare,
                               OPTION_SETUP_TABLES_DONE);
}


static int mysql_multi_delete_prepare_tester(THD *thd)
{
  uint table_count;
  return mysql_multi_delete_prepare(thd, &table_count);
}


static bool mysql_test_multidelete(Prepared_statement *stmt,
                                  TABLE_LIST *tables)
{
  stmt->thd->lex->current_select= &stmt->thd->lex->select_lex;
  if (add_item_to_list(stmt->thd, new Item_null()))
  {
    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 0);
    goto error;
  }

  if (multi_delete_precheck(stmt->thd, tables) ||
      select_like_stmt_test_with_open(stmt, tables,
                                      &mysql_multi_delete_prepare_tester,
                                      OPTION_SETUP_TABLES_DONE))
    goto error;
  if (!tables->table)
  {
    my_error(ER_VIEW_DELETE_MERGE_VIEW, MYF(0),
             tables->view_db.str, tables->view_name.str);
    goto error;
  }
  return FALSE;
error:
  return TRUE;
}


static int mysql_insert_select_prepare_tester(THD *thd)
{
  SELECT_LEX *first_select= &thd->lex->select_lex;
  TABLE_LIST *second_table= first_select->table_list.first->next_local;

  /* Skip first table, which is the table we are inserting in */
  first_select->table_list.first= second_table;
  thd->lex->select_lex.context.table_list=
    thd->lex->select_lex.context.first_name_resolution_table= second_table;

  return mysql_insert_select_prepare(thd);
}


static bool mysql_test_insert_select(Prepared_statement *stmt,
                                     TABLE_LIST *tables)
{
  int res;
  LEX *lex= stmt->lex;
  TABLE_LIST *first_local_table;

  if (tables->table)
  {
    // don't allocate insert_values
    tables->table->insert_values=(uchar *)1;
  }

  if (insert_precheck(stmt->thd, tables))
    return 1;

  /* store it, because mysql_insert_select_prepare_tester change it */
  first_local_table= lex->select_lex.table_list.first;
  DBUG_ASSERT(first_local_table != 0);

  res=
    select_like_stmt_test_with_open(stmt, tables,
                                    &mysql_insert_select_prepare_tester,
                                    OPTION_SETUP_TABLES_DONE);
  /* revert changes  made by mysql_insert_select_prepare_tester */
  lex->select_lex.table_list.first= first_local_table;
  return res;
}


static bool check_prepared_statement(Prepared_statement *stmt)
{
  THD *thd= stmt->thd;
  LEX *lex= stmt->lex;
  SELECT_LEX *select_lex= &lex->select_lex;
  TABLE_LIST *tables;
  enum enum_sql_command sql_command= lex->sql_command;
  int res= 0;
  DBUG_ENTER("check_prepared_statement");
  DBUG_PRINT("enter",("command: %d  param_count: %u",
                      sql_command, stmt->param_count));

  lex->first_lists_tables_same();
  tables= lex->query_tables;

  /* set context for commands which do not use setup_tables */
  lex->select_lex.context.resolve_in_table_list_only(select_lex->
                                                     get_table_list());

  /* Reset warning count for each query that uses tables */
  if (tables)
    thd->get_stmt_da()->opt_clear_warning_info(thd->query_id);

  /*
    For the optimizer trace, this is the symmetric, for statement preparation,
    of what is done at statement execution (in mysql_execute_command()).
  */
  Opt_trace_start ots(thd, tables, sql_command, &lex->var_list,
                      thd->query(), thd->query_length(), NULL,
                      thd->variables.character_set_client);

  Opt_trace_object trace_command(&thd->opt_trace);
  Opt_trace_array trace_command_steps(&thd->opt_trace, "steps");

  if (sql_command_flags[sql_command] & CF_HA_CLOSE)
    mysql_ha_rm_tables(thd, tables);

  /*
    Open temporary tables that are known now. Temporary tables added by
    prelocking will be opened afterwards (during open_tables()).
  */
  if (sql_command_flags[sql_command] & CF_PREOPEN_TMP_TABLES)
  {
    if (open_temporary_tables(thd, tables))
      goto error;
  }

  switch (sql_command) {
  case SQLCOM_REPLACE:
  case SQLCOM_INSERT:
    res= mysql_test_insert(stmt, tables, lex->field_list,
                           lex->many_values,
                           lex->update_list, lex->value_list,
                           lex->duplicates);
    break;

  case SQLCOM_UPDATE:
    res= mysql_test_update(stmt, tables);
    /* mysql_test_update returns 2 if we need to switch to multi-update */
    if (res != 2)
      break;

  case SQLCOM_UPDATE_MULTI:
    res= mysql_test_multiupdate(stmt, tables, res == 2);
    break;

  case SQLCOM_DELETE:
    res= mysql_test_delete(stmt, tables);
    break;
  /* The following allow WHERE clause, so they must be tested like SELECT */
  case SQLCOM_SHOW_DATABASES:
  case SQLCOM_SHOW_TABLES:
  case SQLCOM_SHOW_TRIGGERS:
  case SQLCOM_SHOW_EVENTS:
  case SQLCOM_SHOW_OPEN_TABLES:
  case SQLCOM_SHOW_FIELDS:
  case SQLCOM_SHOW_KEYS:
  case SQLCOM_SHOW_COLLATIONS:
  case SQLCOM_SHOW_CHARSETS:
  case SQLCOM_SHOW_VARIABLES:
  case SQLCOM_SHOW_STATUS:
  case SQLCOM_SHOW_TABLE_STATUS:
  case SQLCOM_SHOW_STATUS_PROC:
  case SQLCOM_SHOW_STATUS_FUNC:
  case SQLCOM_SELECT:
    res= mysql_test_select(stmt, tables);
    if (res == 2)
    {
      /* Statement and field info has already been sent */
      DBUG_RETURN(FALSE);
    }
    break;
  case SQLCOM_CREATE_TABLE:
    res= mysql_test_create_table(stmt);
    break;

  case SQLCOM_CREATE_VIEW:
    if (lex->create_view_mode == VIEW_ALTER)
    {
      my_message(ER_UNSUPPORTED_PS, ER(ER_UNSUPPORTED_PS), MYF(0));
      goto error;
    }
    res= mysql_test_create_view(stmt);
    break;
  case SQLCOM_DO:
    res= mysql_test_do_fields(stmt, tables, lex->insert_list);
    break;

  case SQLCOM_CALL:
    res= mysql_test_call_fields(stmt, tables, &lex->value_list);
    break;
  case SQLCOM_SET_OPTION:
    res= mysql_test_set_fields(stmt, tables, &lex->var_list);
    break;

  case SQLCOM_DELETE_MULTI:
    res= mysql_test_multidelete(stmt, tables);
    break;

  case SQLCOM_INSERT_SELECT:
  case SQLCOM_REPLACE_SELECT:
    res= mysql_test_insert_select(stmt, tables);
    break;

    /*
      Note that we don't need to have cases in this list if they are
      marked with CF_STATUS_COMMAND in sql_command_flags
    */
  case SQLCOM_DROP_TABLE:
  case SQLCOM_RENAME_TABLE:
  case SQLCOM_ALTER_TABLE:
  case SQLCOM_COMMIT:
  case SQLCOM_CREATE_INDEX:
  case SQLCOM_DROP_INDEX:
  case SQLCOM_ROLLBACK:
  case SQLCOM_TRUNCATE:
  case SQLCOM_DROP_VIEW:
  case SQLCOM_REPAIR:
  case SQLCOM_ANALYZE:
  case SQLCOM_OPTIMIZE:
  case SQLCOM_CHANGE_MASTER:
  case SQLCOM_RESET:
  case SQLCOM_FLUSH:
  case SQLCOM_SLAVE_START:
  case SQLCOM_SLAVE_STOP:
  case SQLCOM_INSTALL_PLUGIN:
  case SQLCOM_UNINSTALL_PLUGIN:
  case SQLCOM_CREATE_DB:
  case SQLCOM_DROP_DB:
  case SQLCOM_ALTER_DB_UPGRADE:
  case SQLCOM_CHECKSUM:
  case SQLCOM_CREATE_USER:
  case SQLCOM_RENAME_USER:
  case SQLCOM_DROP_USER:
  case SQLCOM_ALTER_USER:
  case SQLCOM_ASSIGN_TO_KEYCACHE:
  case SQLCOM_PRELOAD_KEYS:
  case SQLCOM_GRANT:
  case SQLCOM_REVOKE:
  case SQLCOM_KILL:
    break;

  case SQLCOM_PREPARE:
  case SQLCOM_EXECUTE:
  case SQLCOM_DEALLOCATE_PREPARE:
  default:
    /*
      Trivial check of all status commands. This is easier than having
      things in the above case list, as it's less chance for mistakes.
    */
    if (!(sql_command_flags[sql_command] & CF_STATUS_COMMAND))
    {
      /* All other statements are not supported yet. */
      my_message(ER_UNSUPPORTED_PS, ER(ER_UNSUPPORTED_PS), MYF(0));
      goto error;
    }
    break;
  }
  if (res == 0)
    DBUG_RETURN(stmt->is_sql_prepare() ?
                FALSE : (send_prep_stmt(stmt, 0) || thd->protocol->flush()));
error:
  DBUG_RETURN(TRUE);
}

static bool init_param_array(Prepared_statement *stmt)
{
  LEX *lex= stmt->lex;
  if ((stmt->param_count= lex->param_list.elements))
  {
    if (stmt->param_count > (uint) UINT_MAX16)
    {
      /* Error code to be defined in 5.0 */
      my_message(ER_PS_MANY_PARAM, ER(ER_PS_MANY_PARAM), MYF(0));
      return TRUE;
    }
    Item_param **to;
    List_iterator<Item_param> param_iterator(lex->param_list);
    /* Use thd->mem_root as it points at statement mem_root */
    stmt->param_array= (Item_param **)
                       alloc_root(stmt->thd->mem_root,
                                  sizeof(Item_param*) * stmt->param_count);
    if (!stmt->param_array)
      return TRUE;
    for (to= stmt->param_array;
         to < stmt->param_array + stmt->param_count;
         ++to)
    {
      *to= param_iterator++;
    }
  }
  return FALSE;
}


void mysqld_stmt_prepare(THD *thd, const char *packet, uint packet_length)
{
  Protocol *save_protocol= thd->protocol;
  Prepared_statement *stmt;
  DBUG_ENTER("mysqld_stmt_prepare");

  DBUG_PRINT("prep_query", ("%s", packet));

  /* First of all clear possible warnings from the previous command */
  mysql_reset_thd_for_next_command(thd);

  if (! (stmt= new Prepared_statement(thd)))
    DBUG_VOID_RETURN; /* out of memory: error is set in Sql_alloc */

  if (thd->stmt_map.insert(thd, stmt))
  {
    /*
      The error is set in the insert. The statement itself
      will be also deleted there (this is how the hash works).
    */
    DBUG_VOID_RETURN;
  }

  thd->protocol= &thd->protocol_binary;

  if (stmt->prepare(packet, packet_length))
  {
    /* Statement map deletes statement on erase */
    thd->stmt_map.erase(stmt);
  }

  thd->protocol= save_protocol;

  sp_cache_enforce_limit(thd->sp_proc_cache, stored_program_cache_size);
  sp_cache_enforce_limit(thd->sp_func_cache, stored_program_cache_size);

  /* check_prepared_statemnt sends the metadata packet in case of success */
  DBUG_VOID_RETURN;
}

static const char *get_dynamic_sql_string(LEX *lex, uint *query_len)
{
  THD *thd= lex->thd;
  char *query_str= 0;

  if (lex->prepared_stmt_code_is_varref)
  {
    /* This is PREPARE stmt FROM or EXECUTE IMMEDIATE @var. */
    String str;
    const CHARSET_INFO *to_cs= thd->variables.collation_connection;
    bool needs_conversion;
    user_var_entry *entry;
    String *var_value= &str;
    uint32 unused, len;
    /*
      Convert @var contents to string in connection character set. Although
      it is known that int/real/NULL value cannot be a valid query we still
      convert it for error messages to be uniform.
    */
    if ((entry=
         (user_var_entry*)my_hash_search(&thd->user_vars,
                                         (uchar*)lex->prepared_stmt_code.str,
                                         lex->prepared_stmt_code.length))
        && entry->ptr())
    {
      my_bool is_var_null;
      var_value= entry->val_str(&is_var_null, &str, NOT_FIXED_DEC);
      /*
        NULL value of variable checked early as entry->value so here
        we can't get NULL in normal conditions
      */
      DBUG_ASSERT(!is_var_null);
      if (!var_value)
        goto end;
    }
    else
    {
      /*
        variable absent or equal to NULL, so we need to set variable to
        something reasonable to get a readable error message during parsing
      */
      str.set(STRING_WITH_LEN("NULL"), &my_charset_latin1);
    }

    needs_conversion= String::needs_conversion(var_value->length(),
                                               var_value->charset(), to_cs,
                                               &unused);

    len= (needs_conversion ? var_value->length() * to_cs->mbmaxlen :
          var_value->length());
    if (!(query_str= (char*) alloc_root(thd->mem_root, len+1)))
      goto end;

    if (needs_conversion)
    {
      uint dummy_errors;
      len= copy_and_convert(query_str, len, to_cs, var_value->ptr(),
                            var_value->length(), var_value->charset(),
                            &dummy_errors);
    }
    else
      memcpy(query_str, var_value->ptr(), var_value->length());
    query_str[len]= '\0';                       // Safety (mostly for debug)
    *query_len= len;
  }
  else
  {
    query_str= lex->prepared_stmt_code.str;
    *query_len= lex->prepared_stmt_code.length;
  }
end:
  return query_str;
}


void mysql_sql_stmt_prepare(THD *thd)
{
  LEX *lex= thd->lex;
  LEX_STRING *name= &lex->prepared_stmt_name;
  Prepared_statement *stmt;
  const char *query;
  uint query_len= 0;
  DBUG_ENTER("mysql_sql_stmt_prepare");

  if ((stmt= (Prepared_statement*) thd->stmt_map.find_by_name(name)))
  {
    /*
      If there is a statement with the same name, remove it. It is ok to
      remove old and fail to insert a new one at the same time.
    */
    if (stmt->is_in_use())
    {
      my_error(ER_PS_NO_RECURSION, MYF(0));
      DBUG_VOID_RETURN;
    }

    stmt->deallocate();
  }

  if (! (query= get_dynamic_sql_string(lex, &query_len)) ||
      ! (stmt= new Prepared_statement(thd)))
  {
    DBUG_VOID_RETURN;                           /* out of memory */
  }

  stmt->set_sql_prepare();

  /* Set the name first, insert should know that this statement has a name */
  if (stmt->set_name(name))
  {
    delete stmt;
    DBUG_VOID_RETURN;
  }

  if (thd->stmt_map.insert(thd, stmt))
  {
    /* The statement is deleted and an error is set if insert fails */
    DBUG_VOID_RETURN;
  }

  if (stmt->prepare(query, query_len))
  {
    /* Statement map deletes the statement on erase */
    thd->stmt_map.erase(stmt);
  }
  else
    my_ok(thd, 0L, 0L, "Statement prepared");

  DBUG_VOID_RETURN;
}

void reinit_stmt_before_use(THD *thd, LEX *lex)
{
  SELECT_LEX *sl= lex->all_selects_list;
  DBUG_ENTER("reinit_stmt_before_use");

  /*
    We have to update "thd" pointer in LEX, all its units and in LEX::result,
    since statements which belong to trigger body are associated with TABLE
    object and because of this can be used in different threads.
  */
  lex->thd= thd;

  if (lex->empty_field_list_on_rset)
  {
    lex->empty_field_list_on_rset= 0;
    lex->field_list.empty();
  }
  for (; sl; sl= sl->next_select_in_list())
  {
    if (!sl->first_execution)
    {
      /* remove option which was put by mysql_explain_unit() */
      sl->options&= ~SELECT_DESCRIBE;

      /* see unique_table() */
      sl->exclude_from_table_unique_test= FALSE;

      /*
        Copy WHERE, HAVING clause pointers to avoid damaging them
        by optimisation
      */
      if (sl->prep_where)
      {
        sl->where= sl->prep_where->copy_andor_structure(thd);
        sl->where->cleanup();
      }
      else
        sl->where= NULL;
      if (sl->prep_having)
      {
        sl->having= sl->prep_having->copy_andor_structure(thd);
        sl->having->cleanup();
      }
      else
        sl->having= NULL;
      DBUG_ASSERT(sl->join == 0);
      ORDER *order;
      /* Fix GROUP list */
      if (sl->group_list_ptrs && sl->group_list_ptrs->size() > 0)
      {
        for (uint ix= 0; ix < sl->group_list_ptrs->size() - 1; ++ix)
        {
          order= sl->group_list_ptrs->at(ix);
          order->next= sl->group_list_ptrs->at(ix+1);
        }
      }
      for (order= sl->group_list.first; order; order= order->next)
        order->item= &order->item_ptr;
      /* Fix ORDER list */
      if (sl->order_list_ptrs && sl->order_list_ptrs->size() > 0)
      {
        for (uint ix= 0; ix < sl->order_list_ptrs->size() - 1; ++ix)
        {
          order= sl->order_list_ptrs->at(ix);
          order->next= sl->order_list_ptrs->at(ix+1);
        }
      }
      for (order= sl->order_list.first; order; order= order->next)
        order->item= &order->item_ptr;

      /* clear the no_error flag for INSERT/UPDATE IGNORE */
      sl->no_error= FALSE;
    }
    {
      SELECT_LEX_UNIT *unit= sl->master_unit();
      unit->unclean();
      unit->types.empty();
      /* for derived tables & PS (which can't be reset by Item_subquery) */
      unit->reinit_exec_mechanism();
      unit->set_thd(thd);
    }
  }

  /*
    TODO: When the new table structure is ready, then have a status bit
    to indicate the table is altered, and re-do the setup_*
    and open the tables back.
  */
  /*
    NOTE: We should reset whole table list here including all tables added
    by prelocking algorithm (it is not a problem for substatements since
    they have their own table list).
  */
  for (TABLE_LIST *tables= lex->query_tables;
       tables;
       tables= tables->next_global)
  {
    tables->reinit_before_use(thd);
  }

  /* Reset MDL tickets for procedures/functions */
  for (Sroutine_hash_entry *rt=
         (Sroutine_hash_entry*)thd->lex->sroutines_list.first;
       rt; rt= rt->next)
    rt->mdl_request.ticket= NULL;

  /*
    Cleanup of the special case of DELETE t1, t2 FROM t1, t2, t3 ...
    (multi-delete).  We do a full clean up, although at the moment all we
    need to clean in the tables of MULTI-DELETE list is 'table' member.
  */
  for (TABLE_LIST *tables= lex->auxiliary_table_list.first;
       tables;
       tables= tables->next_global)
  {
    tables->reinit_before_use(thd);
  }
  lex->current_select= &lex->select_lex;

  /* restore original list used in INSERT ... SELECT */
  if (lex->leaf_tables_insert)
    lex->select_lex.leaf_tables= lex->leaf_tables_insert;

  if (lex->result)
  {
    lex->result->cleanup();
    lex->result->set_thd(thd);
  }
  lex->allow_sum_func= 0;
  lex->in_sum_func= NULL;
  DBUG_VOID_RETURN;
}


static void reset_stmt_params(Prepared_statement *stmt)
{
  Item_param **item= stmt->param_array;
  Item_param **end= item + stmt->param_count;
  for (;item < end ; ++item)
    (**item).reset();
}


void mysqld_stmt_execute(THD *thd, char *packet_arg, uint packet_length)
{
  uchar *packet= (uchar*)packet_arg; // GCC 4.0.1 workaround
  ulong stmt_id;
  ulong flags;
  /* Query text for binary, general or slow log, if any of them is open */
  String expanded_query;
  uchar *packet_end= packet + packet_length;
  Prepared_statement *stmt;
  Protocol *save_protocol= thd->protocol;
  bool open_cursor;
  DBUG_ENTER("mysqld_stmt_execute");

  if (packet + 9 > packet_end)
  {
    my_error(ER_MALFORMED_PACKET, MYF(0));
    DBUG_VOID_RETURN;
  }

  stmt_id= uint4korr(packet);
  flags= (ulong) packet[4];
  packet+= 9;                               /* stmt_id + 5 bytes of flags */

  /* First of all clear possible warnings from the previous command */
  mysql_reset_thd_for_next_command(thd);

  if (!(stmt= find_prepared_statement(thd, stmt_id)))
  {
    char llbuf[22];
    my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0), static_cast<int>(sizeof(llbuf)),
             llstr(stmt_id, llbuf), "mysqld_stmt_execute");
    DBUG_VOID_RETURN;
  }

#if defined(ENABLED_PROFILING)
  thd->profiling.set_query_source(stmt->query(), stmt->query_length());
#endif
  DBUG_PRINT("exec_query", ("%s", stmt->query()));
  DBUG_PRINT("info",("stmt: 0x%lx", (long) stmt));

  open_cursor= test(flags & (ulong) CURSOR_TYPE_READ_ONLY);

  thd->protocol= &thd->protocol_binary;
  stmt->execute_loop(&expanded_query, open_cursor, packet, packet_end);
  thd->protocol= save_protocol;

  sp_cache_enforce_limit(thd->sp_proc_cache, stored_program_cache_size);
  sp_cache_enforce_limit(thd->sp_func_cache, stored_program_cache_size);

  /* Close connection socket; for use with client testing (Bug#43560). */
  DBUG_EXECUTE_IF("close_conn_after_stmt_execute", vio_shutdown(thd->net.vio););

  DBUG_VOID_RETURN;
}


void mysql_sql_stmt_execute(THD *thd)
{
  LEX *lex= thd->lex;
  Prepared_statement *stmt;
  LEX_STRING *name= &lex->prepared_stmt_name;
  /* Query text for binary, general or slow log, if any of them is open */
  String expanded_query;
  DBUG_ENTER("mysql_sql_stmt_execute");
  DBUG_PRINT("info", ("EXECUTE: %.*s\n", (int) name->length, name->str));

  if (!(stmt= (Prepared_statement*) thd->stmt_map.find_by_name(name)))
  {
    my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0),
             static_cast<int>(name->length), name->str, "EXECUTE");
    DBUG_VOID_RETURN;
  }

  if (stmt->param_count != lex->prepared_stmt_params.elements)
  {
    my_error(ER_WRONG_ARGUMENTS, MYF(0), "EXECUTE");
    DBUG_VOID_RETURN;
  }

  DBUG_PRINT("info",("stmt: 0x%lx", (long) stmt));

  (void) stmt->execute_loop(&expanded_query, FALSE, NULL, NULL);

  DBUG_VOID_RETURN;
}


void mysqld_stmt_fetch(THD *thd, char *packet, uint packet_length)
{
  /* assume there is always place for 8-16 bytes */
  ulong stmt_id;
  ulong num_rows;
  Prepared_statement *stmt;
  Statement stmt_backup;
  Server_side_cursor *cursor;
  DBUG_ENTER("mysqld_stmt_fetch");

  if (packet_length < 8)
  {
    my_error(ER_MALFORMED_PACKET, MYF(0));
    DBUG_VOID_RETURN;
  }
  stmt_id= uint4korr(packet);
  num_rows= uint4korr(packet+4);

  /* First of all clear possible warnings from the previous command */
  mysql_reset_thd_for_next_command(thd);
  status_var_increment(thd->status_var.com_stmt_fetch);
  if (!(stmt= find_prepared_statement(thd, stmt_id)))
  {
    char llbuf[22];
    my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0), static_cast<int>(sizeof(llbuf)),
             llstr(stmt_id, llbuf), "mysqld_stmt_fetch");
    DBUG_VOID_RETURN;
  }

  cursor= stmt->cursor;
  if (!cursor)
  {
    my_error(ER_STMT_HAS_NO_OPEN_CURSOR, MYF(0), stmt_id);
    DBUG_VOID_RETURN;
  }

  thd->stmt_arena= stmt;
  thd->set_n_backup_statement(stmt, &stmt_backup);

  cursor->fetch(num_rows);

  if (!cursor->is_open())
  {
    stmt->close_cursor();
    reset_stmt_params(stmt);
  }

  thd->restore_backup_statement(stmt, &stmt_backup);
  thd->stmt_arena= thd;

  DBUG_VOID_RETURN;
}


void mysqld_stmt_reset(THD *thd, char *packet, uint packet_length)
{
  ulong stmt_id;
  Prepared_statement *stmt;
  DBUG_ENTER("mysqld_stmt_reset");

  if (packet_length < 4)
  {
    my_error(ER_MALFORMED_PACKET, MYF(0));
    DBUG_VOID_RETURN;
  }

  stmt_id= uint4korr(packet);

  /* First of all clear possible warnings from the previous command */
  mysql_reset_thd_for_next_command(thd);

  status_var_increment(thd->status_var.com_stmt_reset);
  if (!(stmt= find_prepared_statement(thd, stmt_id)))
  {
    char llbuf[22];
    my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0), static_cast<int>(sizeof(llbuf)),
             llstr(stmt_id, llbuf), "mysqld_stmt_reset");
    DBUG_VOID_RETURN;
  }

  stmt->close_cursor();

  /*
    Clear parameters from data which could be set by
    mysqld_stmt_send_long_data() call.
  */
  reset_stmt_params(stmt);

  stmt->state= Query_arena::STMT_PREPARED;

  general_log_print(thd, thd->get_command(), NullS);

  my_ok(thd);

  DBUG_VOID_RETURN;
}


void mysqld_stmt_close(THD *thd, char *packet, uint packet_length)
{
  /* There is always space for 4 bytes in packet buffer */
  ulong stmt_id;
  Prepared_statement *stmt;
  DBUG_ENTER("mysqld_stmt_close");

  if (packet_length < 4)
  {
    my_error(ER_MALFORMED_PACKET, MYF(0));
    DBUG_VOID_RETURN;
  }

  stmt_id= uint4korr(packet);

  thd->get_stmt_da()->disable_status();

  if (!(stmt= find_prepared_statement(thd, stmt_id)))
    DBUG_VOID_RETURN;

  /*
    The only way currently a statement can be deallocated when it's
    in use is from within Dynamic SQL.
  */
  DBUG_ASSERT(! stmt->is_in_use());
  stmt->deallocate();
  general_log_print(thd, thd->get_command(), NullS);

  DBUG_VOID_RETURN;
}


void mysql_sql_stmt_close(THD *thd)
{
  Prepared_statement* stmt;
  LEX_STRING *name= &thd->lex->prepared_stmt_name;
  DBUG_PRINT("info", ("DEALLOCATE PREPARE: %.*s\n", (int) name->length,
                      name->str));

  if (! (stmt= (Prepared_statement*) thd->stmt_map.find_by_name(name)))
    my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0),
             static_cast<int>(name->length), name->str, "DEALLOCATE PREPARE");
  else if (stmt->is_in_use())
    my_error(ER_PS_NO_RECURSION, MYF(0));
  else
  {
    stmt->deallocate();
    my_ok(thd);
  }
}


void mysql_stmt_get_longdata(THD *thd, char *packet, ulong packet_length)
{
  ulong stmt_id;
  uint param_number;
  Prepared_statement *stmt;
  Item_param *param;
#ifndef EMBEDDED_LIBRARY
  char *packet_end= packet + packet_length;
#endif
  DBUG_ENTER("mysql_stmt_get_longdata");

  status_var_increment(thd->status_var.com_stmt_send_long_data);

  thd->get_stmt_da()->disable_status();
#ifndef EMBEDDED_LIBRARY
  /* Minimal size of long data packet is 6 bytes */
  if (packet_length < MYSQL_LONG_DATA_HEADER)
    DBUG_VOID_RETURN;
#endif

  stmt_id= uint4korr(packet);
  packet+= 4;

  if (!(stmt=find_prepared_statement(thd, stmt_id)))
    DBUG_VOID_RETURN;

  param_number= uint2korr(packet);
  packet+= 2;
#ifndef EMBEDDED_LIBRARY
  if (param_number >= stmt->param_count)
  {
    /* Error will be sent in execute call */
    stmt->state= Query_arena::STMT_ERROR;
    stmt->last_errno= ER_WRONG_ARGUMENTS;
    sprintf(stmt->last_error, ER(ER_WRONG_ARGUMENTS),
            "mysqld_stmt_send_long_data");
    DBUG_VOID_RETURN;
  }
#endif

  param= stmt->param_array[param_number];

  Diagnostics_area new_stmt_da(thd->query_id, false);
  Diagnostics_area *save_stmt_da= thd->get_stmt_da();

  thd->set_stmt_da(&new_stmt_da);

#ifndef EMBEDDED_LIBRARY
  param->set_longdata(packet, (ulong) (packet_end - packet));
#else
  param->set_longdata(thd->extra_data, thd->extra_length);
#endif
  if (thd->get_stmt_da()->is_error())
  {
    stmt->state= Query_arena::STMT_ERROR;
    stmt->last_errno= thd->get_stmt_da()->sql_errno();
    strncpy(stmt->last_error, thd->get_stmt_da()->message(), MYSQL_ERRMSG_SIZE);
  }
  thd->set_stmt_da(save_stmt_da);

  general_log_print(thd, thd->get_command(), NullS);

  DBUG_VOID_RETURN;
}


/***************************************************************************
 Select_fetch_protocol_binary
****************************************************************************/

Select_fetch_protocol_binary::Select_fetch_protocol_binary(THD *thd_arg)
  :protocol(thd_arg)
{}

bool Select_fetch_protocol_binary::send_result_set_metadata(List<Item> &list, uint flags)
{
  bool rc;
  Protocol *save_protocol= thd->protocol;

  /*
    Protocol::send_result_set_metadata caches the information about column types:
    this information is later used to send data. Therefore, the same
    dedicated Protocol object must be used for all operations with
    a cursor.
  */
  thd->protocol= &protocol;
  rc= select_send::send_result_set_metadata(list, flags);
  thd->protocol= save_protocol;

  return rc;
}

bool Select_fetch_protocol_binary::send_eof()
{
  /*
    Don't send EOF if we're in error condition (which implies we've already
    sent or are sending an error)
  */
  if (thd->is_error())
    return true;

  ::my_eof(thd);
  return false;
}


bool
Select_fetch_protocol_binary::send_data(List<Item> &fields)
{
  Protocol *save_protocol= thd->protocol;
  bool rc;

  thd->protocol= &protocol;
  rc= select_send::send_data(fields);
  thd->protocol= save_protocol;
  return rc;
}

/*******************************************************************
* Reprepare_observer
*******************************************************************/
bool
Reprepare_observer::report_error(THD *thd)
{
  /*
    This 'error' is purely internal to the server:
    - No exception handler is invoked,
    - No condition is added in the condition area (warn_list).
    The diagnostics area is set to an error status to enforce
    that this thread execution stops and returns to the caller,
    backtracking all the way to Prepared_statement::execute_loop().
  */
  thd->get_stmt_da()->set_error_status(ER_NEED_REPREPARE);
  m_invalidated= TRUE;

  return TRUE;
}


/*******************************************************************
* Server_runnable
*******************************************************************/

Server_runnable::~Server_runnable()
{
}


Execute_sql_statement::
Execute_sql_statement(LEX_STRING sql_text)
  :m_sql_text(sql_text)
{}


bool
Execute_sql_statement::execute_server_code(THD *thd)
{
  PSI_statement_locker *parent_locker;
  bool error;

  if (alloc_query(thd, m_sql_text.str, m_sql_text.length))
    return TRUE;

  Parser_state parser_state;
  if (parser_state.init(thd, thd->query(), thd->query_length()))
    return TRUE;

  parser_state.m_lip.multi_statements= FALSE;
  lex_start(thd);

  parent_locker= thd->m_statement_psi;
  thd->m_statement_psi= NULL;
  error= parse_sql(thd, &parser_state, NULL) || thd->is_error();
  thd->m_statement_psi= parent_locker;

  if (error)
    goto end;

  thd->lex->set_trg_event_type_for_tables();

  parent_locker= thd->m_statement_psi;
  thd->m_statement_psi= NULL;
  /*
    Rewrite first (if needed); execution might replace passwords
    with hashes in situ without flagging it, and then we'd make
    a hash of that hash.
  */
  rewrite_query_if_needed(thd);
  error= mysql_execute_command(thd) ;
  thd->m_statement_psi= parent_locker;

  /* report error issued during command execution */
  if (error == 0)
    log_execute_line(thd);

end:
  lex_end(thd->lex);

  return error;
}

/***************************************************************************
 Prepared_statement
****************************************************************************/

Prepared_statement::Prepared_statement(THD *thd_arg)
  :Statement(NULL, &main_mem_root,
             STMT_INITIALIZED, ++thd_arg->statement_id_counter),
  thd(thd_arg),
  result(thd_arg),
  param_array(0),
  cursor(0),
  param_count(0),
  last_errno(0),
  flags((uint) IS_IN_USE)
{
  init_sql_alloc(&main_mem_root, thd_arg->variables.query_alloc_block_size,
                  thd_arg->variables.query_prealloc_size);
  *last_error= '\0';
}


void Prepared_statement::setup_set_params()
{
  /*
    Note: BUG#25843 applies here too (query cache lookup uses thd->db, not
    db from "prepare" time).
  */
  if (query_cache_maybe_disabled(thd)) // we won't expand the query
    lex->safe_to_cache_query= FALSE;   // so don't cache it at Execution

  /*
    Decide if we have to expand the query (because we must write it to logs or
    because we want to look it up in the query cache) or not.
  */
  if ((mysql_bin_log.is_open() && is_update_query(lex->sql_command)) ||
      opt_log || opt_slow_log ||
      query_cache_is_cacheable_query(lex))
  {
    set_params_from_vars= insert_params_from_vars_with_log;
#ifndef EMBEDDED_LIBRARY
    set_params= insert_params_with_log;
#else
    set_params_data= emb_insert_params_with_log;
#endif
  }
  else
  {
    set_params_from_vars= insert_params_from_vars;
#ifndef EMBEDDED_LIBRARY
    set_params= insert_params;
#else
    set_params_data= emb_insert_params;
#endif
  }
}


Prepared_statement::~Prepared_statement()
{
  DBUG_ENTER("Prepared_statement::~Prepared_statement");
  DBUG_PRINT("enter",("stmt: 0x%lx  cursor: 0x%lx",
                      (long) this, (long) cursor));
  delete cursor;
  /*
    We have to call free on the items even if cleanup is called as some items,
    like Item_param, don't free everything until free_items()
  */
  free_items();
  if (lex)
  {
    delete lex->result;
    delete (st_lex_local *) lex;
  }
  free_root(&main_mem_root, MYF(0));
  DBUG_VOID_RETURN;
}


Query_arena::Type Prepared_statement::type() const
{
  return PREPARED_STATEMENT;
}


void Prepared_statement::cleanup_stmt()
{
  DBUG_ENTER("Prepared_statement::cleanup_stmt");
  DBUG_PRINT("enter",("stmt: 0x%lx", (long) this));

  cleanup_items(free_list);
  thd->cleanup_after_query();
  thd->rollback_item_tree_changes();

  DBUG_VOID_RETURN;
}


bool Prepared_statement::set_name(LEX_STRING *name_arg)
{
  name.length= name_arg->length;
  name.str= (char*) memdup_root(mem_root, name_arg->str, name_arg->length);
  return name.str == 0;
}


bool
Prepared_statement::set_db(const char *db_arg, uint db_length_arg)
{
  /* Remember the current database. */
  if (db_arg && db_length_arg)
  {
    db= this->strmake(db_arg, db_length_arg);
    db_length= db_length_arg;
  }
  else
  {
    db= NULL;
    db_length= 0;
  }
  return db_arg != NULL && db == NULL;
}

/**************************************************************************
  Common parts of mysql_[sql]_stmt_prepare, mysql_[sql]_stmt_execute.
  Essentially, these functions do all the magic of preparing/executing
  a statement, leaving network communication, input data handling and
  global THD state management to the caller.
***************************************************************************/

bool Prepared_statement::prepare(const char *packet, uint packet_len)
{
  bool error;
  Statement stmt_backup;
  Query_arena *old_stmt_arena;
  PSI_statement_locker *parent_locker= thd->m_statement_psi;
  DBUG_ENTER("Prepared_statement::prepare");
  /*
    If this is an SQLCOM_PREPARE, we also increase Com_prepare_sql.
    However, it seems handy if com_stmt_prepare is increased always,
    no matter what kind of prepare is processed.
  */
  status_var_increment(thd->status_var.com_stmt_prepare);

  if (! (lex= new (mem_root) st_lex_local))
    DBUG_RETURN(TRUE);

  if (set_db(thd->db, thd->db_length))
    DBUG_RETURN(TRUE);

  /*
    alloc_query() uses thd->memroot && thd->query, so we should call
    both of backup_statement() and backup_query_arena() here.
  */
  thd->set_n_backup_statement(this, &stmt_backup);
  thd->set_n_backup_active_arena(this, &stmt_backup);

  if (alloc_query(thd, packet, packet_len))
  {
    thd->restore_backup_statement(this, &stmt_backup);
    thd->restore_active_arena(this, &stmt_backup);
    DBUG_RETURN(TRUE);
  }

  old_stmt_arena= thd->stmt_arena;
  thd->stmt_arena= this;

  Parser_state parser_state;
  if (parser_state.init(thd, thd->query(), thd->query_length()))
  {
    thd->restore_backup_statement(this, &stmt_backup);
    thd->restore_active_arena(this, &stmt_backup);
    thd->stmt_arena= old_stmt_arena;
    DBUG_RETURN(TRUE);
  }

  parser_state.m_lip.stmt_prepare_mode= TRUE;
  parser_state.m_lip.multi_statements= FALSE;

  lex_start(thd);
  lex->context_analysis_only|= CONTEXT_ANALYSIS_ONLY_PREPARE;

  thd->m_statement_psi= NULL;
  error= parse_sql(thd, & parser_state, NULL) ||
    thd->is_error() ||
    init_param_array(this);
  thd->m_statement_psi= parent_locker;

  lex->set_trg_event_type_for_tables();

  /*
    While doing context analysis of the query (in check_prepared_statement)
    we allocate a lot of additional memory: for open tables, JOINs, derived
    tables, etc.  Let's save a snapshot of current parse tree to the
    statement and restore original THD. In cases when some tree
    transformation can be reused on execute, we set again thd->mem_root from
    stmt->mem_root (see setup_wild for one place where we do that).
  */
  thd->restore_active_arena(this, &stmt_backup);

  /*
    If called from a stored procedure, ensure that we won't rollback
    external changes when cleaning up after validation.
  */
  DBUG_ASSERT(thd->change_list.is_empty());

  /*
    Marker used to release metadata locks acquired while the prepared
    statement is being checked.
  */
  MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint();

  /*
   The only case where we should have items in the thd->free_list is
   after stmt->set_params_from_vars(), which may in some cases create
   Item_null objects.
  */

  if (error == 0)
    error= check_prepared_statement(this);

  /*
    Currently CREATE PROCEDURE/TRIGGER/EVENT are prohibited in prepared
    statements: ensure we have no memory leak here if by someone tries
    to PREPARE stmt FROM "CREATE PROCEDURE ..."
  */
  DBUG_ASSERT(lex->sphead == NULL || error != 0);
  /* The order is important */
  lex->unit.cleanup();

  /* No need to commit statement transaction, it's not started. */
  DBUG_ASSERT(thd->transaction.stmt.is_empty());

  close_thread_tables(thd);
  thd->mdl_context.rollback_to_savepoint(mdl_savepoint);

  /*
    Transaction rollback was requested since MDL deadlock was discovered
    while trying to open tables. Rollback transaction in all storage
    engines including binary log and release all locks.

    Once dynamic SQL is allowed as substatements the below if-statement
    has to be adjusted to not do rollback in substatement.
  */
  DBUG_ASSERT(! thd->in_sub_stmt);
  if (thd->transaction_rollback_request)
  {
    trans_rollback_implicit(thd);
    thd->mdl_context.release_transactional_locks();
  }

  lex_end(lex);

  rewrite_query_if_needed(thd);

  cleanup_stmt();
  thd->restore_backup_statement(this, &stmt_backup);
  thd->stmt_arena= old_stmt_arena;

  if (error == 0)
  {
    setup_set_params();
    lex->context_analysis_only&= ~CONTEXT_ANALYSIS_ONLY_PREPARE;
    state= Query_arena::STMT_PREPARED;
    flags&= ~ (uint) IS_IN_USE;

    /*
      Log COM_STMT_PREPARE to the general log. Note, that in case of SQL
      prepared statements this causes two records to be output:

      Query       PREPARE stmt from @user_variable
      Prepare     <statement SQL text>

      This is considered user-friendly, since in the  second log Entry
      we output the actual statement text rather than the variable name.

      Rewriting/password obfuscation:

      - If we're preparing from a string literal rather than from a
        variable, the literal is elided in the "Query" log line, as
        it may contain a password.  (As we've parsed the PREPARE statement,
        but not the statement to prepare yet, we don't know at that point.)
        Eliding the literal is fine, as we'll print it in the next log line
        ("Prepare"), anyway.

      - Any passwords in the "Prepare" line should be substituted with their
        hashes, or a notice.

      Do not print anything if this is an SQL prepared statement and
      we're inside a stored procedure (also called Dynamic SQL) --
      sub-statements inside stored procedures are not logged into
      the general log.
    */
    if (thd->sp_runtime_ctx == NULL)
    {
      if (thd->rewritten_query.length())
        logger.general_log_write(thd, COM_STMT_PREPARE,
                                 thd->rewritten_query.c_ptr_safe(),
                                 thd->rewritten_query.length());
      else
        logger.general_log_write(thd, COM_STMT_PREPARE,
                                 query(), query_length());
    }
  }
  DBUG_RETURN(error);
}


bool
Prepared_statement::set_parameters(String *expanded_query,
                                   uchar *packet, uchar *packet_end)
{
  bool is_sql_ps= packet == NULL;
  bool res= FALSE;

  if (is_sql_ps)
  {
    /* SQL prepared statement */
    res= set_params_from_vars(this, thd->lex->prepared_stmt_params,
                              expanded_query);
  }
  else if (param_count)
  {
#ifndef EMBEDDED_LIBRARY
    uchar *null_array= packet;
    res= (setup_conversion_functions(this, &packet, packet_end) ||
          set_params(this, null_array, packet, packet_end, expanded_query));
#else
    /*
      In embedded library we re-install conversion routines each time
      we set parameters, and also we don't need to parse packet.
      So we do it in one function.
    */
    res= set_params_data(this, expanded_query);
#endif
  }
  if (res)
  {
    my_error(ER_WRONG_ARGUMENTS, MYF(0),
             is_sql_ps ? "EXECUTE" : "mysqld_stmt_execute");
    reset_stmt_params(this);
  }
  return res;
}


bool
Prepared_statement::execute_loop(String *expanded_query,
                                 bool open_cursor,
                                 uchar *packet,
                                 uchar *packet_end)
{
  const int MAX_REPREPARE_ATTEMPTS= 3;
  Reprepare_observer reprepare_observer;
  bool error;
  int reprepare_attempt= 0;

  /* Check if we got an error when sending long data */
  if (state == Query_arena::STMT_ERROR)
  {
    my_message(last_errno, last_error, MYF(0));
    return TRUE;
  }

  if (set_parameters(expanded_query, packet, packet_end))
    return TRUE;

  if (unlikely(thd->security_ctx->password_expired && 
               !lex->is_change_password))
  {
    my_error(ER_MUST_CHANGE_PASSWORD, MYF(0));
    return true;
  }

reexecute:
  /*
    If the free_list is not empty, we'll wrongly free some externally
    allocated items when cleaning up after validation of the prepared
    statement.
  */
  DBUG_ASSERT(thd->free_list == NULL);

  /*
    Install the metadata observer. If some metadata version is
    different from prepare time and an observer is installed,
    the observer method will be invoked to push an error into
    the error stack.
  */
  Reprepare_observer *stmt_reprepare_observer= NULL;

  if (sql_command_flags[lex->sql_command] & CF_REEXECUTION_FRAGILE)
  {
    reprepare_observer.reset_reprepare_observer();
    stmt_reprepare_observer = &reprepare_observer;
  }

  thd->push_reprepare_observer(stmt_reprepare_observer);

  error= execute(expanded_query, open_cursor) || thd->is_error();

  thd->pop_reprepare_observer();

  if ((sql_command_flags[lex->sql_command] & CF_REEXECUTION_FRAGILE) &&
      error && !thd->is_fatal_error && !thd->killed &&
      reprepare_observer.is_invalidated() &&
      reprepare_attempt++ < MAX_REPREPARE_ATTEMPTS)
  {
    DBUG_ASSERT(thd->get_stmt_da()->sql_errno() == ER_NEED_REPREPARE);
    thd->clear_error();

    error= reprepare();

    if (! error)                                /* Success */
      goto reexecute;
  }
  reset_stmt_params(this);

  return error;
}


bool
Prepared_statement::execute_server_runnable(Server_runnable *server_runnable)
{
  Statement stmt_backup;
  bool error;
  Query_arena *save_stmt_arena= thd->stmt_arena;
  Item_change_list save_change_list;
  thd->change_list.move_elements_to(&save_change_list);

  state= STMT_CONVENTIONAL_EXECUTION;

  if (!(lex= new (mem_root) st_lex_local))
    return TRUE;

  thd->set_n_backup_statement(this, &stmt_backup);
  thd->set_n_backup_active_arena(this, &stmt_backup);
  thd->stmt_arena= this;

  error= server_runnable->execute_server_code(thd);

  thd->cleanup_after_query();

  thd->restore_active_arena(this, &stmt_backup);
  thd->restore_backup_statement(this, &stmt_backup);
  thd->stmt_arena= save_stmt_arena;

  save_change_list.move_elements_to(&thd->change_list);

  /* Items and memory will freed in destructor */

  return error;
}


bool
Prepared_statement::reprepare()
{
  char saved_cur_db_name_buf[NAME_LEN+1];
  LEX_STRING saved_cur_db_name=
    { saved_cur_db_name_buf, sizeof(saved_cur_db_name_buf) };
  LEX_STRING stmt_db_name= { db, db_length };
  bool cur_db_changed;
  bool error;

  Prepared_statement copy(thd);

  copy.set_sql_prepare(); /* To suppress sending metadata to the client. */

  status_var_increment(thd->status_var.com_stmt_reprepare);

  if (mysql_opt_change_db(thd, &stmt_db_name, &saved_cur_db_name, TRUE,
                          &cur_db_changed))
    return TRUE;

  error= ((name.str && copy.set_name(&name)) ||
          copy.prepare(query(), query_length()) ||
          validate_metadata(&copy));

  if (cur_db_changed)
    mysql_change_db(thd, &saved_cur_db_name, TRUE);

  if (! error)
  {
    swap_prepared_statement(&copy);
    swap_parameter_array(param_array, copy.param_array, param_count);
#ifndef DBUG_OFF
    is_reprepared= TRUE;
#endif
    /*
      Clear possible warnings during reprepare, it has to be completely
      transparent to the user. We use clear_warning_info() since
      there were no separate query id issued for re-prepare.
      Sic: we can't simply silence warnings during reprepare, because if
      it's failed, we need to return all the warnings to the user.
    */
    thd->get_stmt_da()->clear_warning_info(thd->query_id);
  }
  return error;
}


bool Prepared_statement::validate_metadata(Prepared_statement *copy)
{
  if (is_sql_prepare() || lex->describe)
    return FALSE;

  if (lex->select_lex.item_list.elements !=
      copy->lex->select_lex.item_list.elements)
  {
    thd->server_status|= SERVER_STATUS_METADATA_CHANGED;
  }

  return FALSE;
}


void
Prepared_statement::swap_prepared_statement(Prepared_statement *copy)
{
  Statement tmp_stmt;

  /* Swap memory roots. */
  swap_variables(MEM_ROOT, main_mem_root, copy->main_mem_root);

  /* Swap the arenas */
  tmp_stmt.set_query_arena(this);
  set_query_arena(copy);
  copy->set_query_arena(&tmp_stmt);

  /* Swap the statement parent classes */
  tmp_stmt.set_statement(this);
  set_statement(copy);
  copy->set_statement(&tmp_stmt);

  /* Swap ids back, we need the original id */
  swap_variables(ulong, id, copy->id);
  /* Swap mem_roots back, they must continue pointing at the main_mem_roots */
  swap_variables(MEM_ROOT *, mem_root, copy->mem_root);
  /*
    Swap the old and the new parameters array. The old array
    is allocated in the old arena.
  */
  swap_variables(Item_param **, param_array, copy->param_array);
  /* Don't swap flags: the copy has IS_SQL_PREPARE always set. */
  /* swap_variables(uint, flags, copy->flags); */
  /* Swap names, the old name is allocated in the wrong memory root */
  swap_variables(LEX_STRING, name, copy->name);
  /* Ditto */
  swap_variables(char *, db, copy->db);

  DBUG_ASSERT(db_length == copy->db_length);
  DBUG_ASSERT(param_count == copy->param_count);
  DBUG_ASSERT(thd == copy->thd);
  last_error[0]= '\0';
  last_errno= 0;
}


bool Prepared_statement::execute(String *expanded_query, bool open_cursor)
{
  Statement stmt_backup;
  Query_arena *old_stmt_arena;
  bool error= TRUE;

  char saved_cur_db_name_buf[NAME_LEN+1];
  LEX_STRING saved_cur_db_name=
    { saved_cur_db_name_buf, sizeof(saved_cur_db_name_buf) };
  bool cur_db_changed;

  LEX_STRING stmt_db_name= { db, db_length };

  status_var_increment(thd->status_var.com_stmt_execute);

  if (flags & (uint) IS_IN_USE)
  {
    my_error(ER_PS_NO_RECURSION, MYF(0));
    return TRUE;
  }

  /*
    For SHOW VARIABLES lex->result is NULL, as it's a non-SELECT
    command. For such queries we don't return an error and don't
    open a cursor -- the client library will recognize this case and
    materialize the result set.
    For SELECT statements lex->result is created in
    check_prepared_statement. lex->result->simple_select() is FALSE
    in INSERT ... SELECT and similar commands.
  */

  if (open_cursor && lex->result && lex->result->check_simple_select())
  {
    DBUG_PRINT("info",("Cursor asked for not SELECT stmt"));
    return TRUE;
  }

  /* In case the command has a call to SP which re-uses this statement name */
  flags|= IS_IN_USE;

  close_cursor();

  /*
    If the free_list is not empty, we'll wrongly free some externally
    allocated items when cleaning up after execution of this statement.
  */
  DBUG_ASSERT(thd->change_list.is_empty());

  /* 
   The only case where we should have items in the thd->free_list is
   after stmt->set_params_from_vars(), which may in some cases create
   Item_null objects.
  */

  thd->set_n_backup_statement(this, &stmt_backup);

  /*
    Change the current database (if needed).

    Force switching, because the database of the prepared statement may be
    NULL (prepared statements can be created while no current database
    selected).
  */

  if (mysql_opt_change_db(thd, &stmt_db_name, &saved_cur_db_name, TRUE,
                          &cur_db_changed))
    goto error;

  /* Allocate query. */

  if (expanded_query->length() &&
      alloc_query(thd, (char*) expanded_query->ptr(),
                  expanded_query->length()))
  {
    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), expanded_query->length());
    goto error;
  }
  /*
    Expanded query is needed for slow logging, so we want thd->query
    to point at it even after we restore from backup. This is ok, as
    expanded query was allocated in thd->mem_root.
  */
  stmt_backup.set_query_inner(thd->query_string);

  /*
    At first execution of prepared statement we may perform logical
    transformations of the query tree. Such changes should be performed
    on the parse tree of current prepared statement and new items should
    be allocated in its memory root. Set the appropriate pointer in THD
    to the arena of the statement.
  */
  old_stmt_arena= thd->stmt_arena;
  thd->stmt_arena= this;
  reinit_stmt_before_use(thd, lex);

  /* Go! */

  if (open_cursor)
    error= mysql_open_cursor(thd, &result, &cursor);
  else
  {
    /*
      Try to find it in the query cache, if not, execute it.
      Note that multi-statements cannot exist here (they are not supported in
      prepared statements).
    */
    if (query_cache_send_result_to_client(thd, thd->query(),
                                          thd->query_length()) <= 0)
    {
      PSI_statement_locker *parent_locker;
      MYSQL_QUERY_EXEC_START(thd->query(),
                             thd->thread_id,
                             (char *) (thd->db ? thd->db : ""),
                             &thd->security_ctx->priv_user[0],
                             (char *) thd->security_ctx->host_or_ip,
                             1);
      parent_locker= thd->m_statement_psi;
      thd->m_statement_psi= NULL;
      /*
        Rewrite first (if needed); execution might replace passwords
        with hashes in situ without flagging it, and then we'd make
        a hash of that hash.
      */
      rewrite_query_if_needed(thd);

      error= mysql_execute_command(thd);
      thd->m_statement_psi= parent_locker;
      MYSQL_QUERY_EXEC_DONE(error);
    }
  }

  /*
    Restore the current database (if changed).

    Force switching back to the saved current database (if changed),
    because it may be NULL. In this case, mysql_change_db() would generate
    an error.
  */

  if (cur_db_changed)
    mysql_change_db(thd, &saved_cur_db_name, TRUE);

  /* Assert that if an error, no cursor is open */
  DBUG_ASSERT(! (error && cursor));

  if (! cursor)
    cleanup_stmt();

  thd->set_statement(&stmt_backup);
  thd->stmt_arena= old_stmt_arena;

  if (state == Query_arena::STMT_PREPARED)
    state= Query_arena::STMT_EXECUTED;

  if (error == 0 && this->lex->sql_command == SQLCOM_CALL)
  {
    if (is_sql_prepare())
      thd->protocol_text.send_out_parameters(&this->lex->param_list);
    else
      thd->protocol->send_out_parameters(&this->lex->param_list);
  }

  /*
    Log COM_STMT_EXECUTE to the general log. Note, that in case of SQL
    prepared statements this causes two records to be output:

    Query       EXECUTE <statement name>
    Execute     <statement SQL text>

    This is considered user-friendly, since in the
    second log entry we output values of parameter markers.

    Rewriting/password obfuscation:

    - Any passwords in the "Execute" line should be substituted with
      their hashes, or a notice.

  */
  if (error == 0)
    log_execute_line(thd);

error:
  flags&= ~ (uint) IS_IN_USE;
  return error;
}


void Prepared_statement::deallocate()
{
  /* We account deallocate in the same manner as mysqld_stmt_close */
  status_var_increment(thd->status_var.com_stmt_close);
  /* Statement map calls delete stmt on erase */
  thd->stmt_map.erase(this);
}


/***************************************************************************
* Ed_result_set
***************************************************************************/
void Ed_result_set::operator delete(void *ptr, size_t size) throw ()
{
  if (ptr)
  {
    /*
      Make a stack copy, otherwise free_root() will attempt to
      write to freed memory.
    */
    MEM_ROOT own_root= ((Ed_result_set*) ptr)->m_mem_root;
    free_root(&own_root, MYF(0));
  }
}


Ed_result_set::Ed_result_set(List<Ed_row> *rows_arg,
                             size_t column_count_arg,
                             MEM_ROOT *mem_root_arg)
  :m_mem_root(*mem_root_arg),
  m_column_count(column_count_arg),
  m_rows(rows_arg),
  m_next_rset(NULL)
{
  /* Take over responsibility for the memory */
  clear_alloc_root(mem_root_arg);
}

/***************************************************************************
* Ed_result_set
***************************************************************************/

Ed_connection::Ed_connection(THD *thd)
  :m_diagnostics_area(thd->query_id, false),
  m_thd(thd),
  m_rsets(0),
  m_current_rset(0)
{
}


void
Ed_connection::free_old_result()
{
  while (m_rsets)
  {
    Ed_result_set *rset= m_rsets->m_next_rset;
    delete m_rsets;
    m_rsets= rset;
  }
  m_current_rset= m_rsets;
  m_diagnostics_area.reset_diagnostics_area();
  m_diagnostics_area.clear_warning_info(m_thd->query_id);
}


bool
Ed_connection::execute_direct(LEX_STRING sql_text)
{
  Execute_sql_statement execute_sql_statement(sql_text);
  DBUG_PRINT("ed_query", ("%s", sql_text.str));

  return execute_direct(&execute_sql_statement);
}


bool Ed_connection::execute_direct(Server_runnable *server_runnable)
{
  bool rc= FALSE;
  Protocol_local protocol_local(m_thd, this);
  Prepared_statement stmt(m_thd);
  Protocol *save_protocol= m_thd->protocol;
  Diagnostics_area *save_diagnostics_area= m_thd->get_stmt_da();

  DBUG_ENTER("Ed_connection::execute_direct");

  free_old_result(); /* Delete all data from previous execution, if any */

  m_thd->protocol= &protocol_local;
  m_thd->set_stmt_da(&m_diagnostics_area);

  rc= stmt.execute_server_runnable(server_runnable);
  m_thd->protocol->end_statement();

  m_thd->protocol= save_protocol;
  m_thd->set_stmt_da(save_diagnostics_area);
  /*
    Protocol_local makes use of m_current_rset to keep
    track of the last result set, while adding result sets to the end.
    Reset it to point to the first result set instead.
  */
  m_current_rset= m_rsets;

  DBUG_RETURN(rc);
}


void
Ed_connection::add_result_set(Ed_result_set *ed_result_set)
{
  if (m_rsets)
  {
    m_current_rset->m_next_rset= ed_result_set;
    /* While appending, use m_current_rset as a pointer to the tail. */
    m_current_rset= ed_result_set;
  }
  else
    m_current_rset= m_rsets= ed_result_set;
}


Ed_result_set *
Ed_connection::store_result_set()
{
  Ed_result_set *ed_result_set;

  DBUG_ASSERT(m_current_rset);

  if (m_current_rset == m_rsets)
  {
    /* Assign the return value */
    ed_result_set= m_current_rset;
    /* Exclude the return value from the list. */
    m_current_rset= m_rsets= m_rsets->m_next_rset;
  }
  else
  {
    Ed_result_set *prev_rset= m_rsets;
    /* Assign the return value. */
    ed_result_set= m_current_rset;

    /* Exclude the return value from the list */
    while (prev_rset->m_next_rset != m_current_rset)
      prev_rset= ed_result_set->m_next_rset;
    m_current_rset= prev_rset->m_next_rset= m_current_rset->m_next_rset;
  }
  ed_result_set->m_next_rset= NULL; /* safety */

  return ed_result_set;
}

/*************************************************************************
* Protocol_local
**************************************************************************/

Protocol_local::Protocol_local(THD *thd, Ed_connection *ed_connection)
  :Protocol(thd),
  m_connection(ed_connection),
  m_rset(NULL),
  m_column_count(0),
  m_current_row(NULL),
  m_current_column(NULL)
{
  clear_alloc_root(&m_rset_root);
}

void Protocol_local::prepare_for_resend()
{
  DBUG_ASSERT(alloc_root_inited(&m_rset_root));

  opt_add_row_to_rset();
  /* Start a new row. */
  m_current_row= (Ed_column *) alloc_root(&m_rset_root,
                                          sizeof(Ed_column) * m_column_count);
  m_current_column= m_current_row;
}


bool Protocol_local::write()
{
  return FALSE;
}

void Protocol_local::opt_add_row_to_rset()
{
  if (m_current_row)
  {
    /* Add the old row to the result set */
    Ed_row *ed_row= new (&m_rset_root) Ed_row(m_current_row, m_column_count);
    if (ed_row)
      m_rset->push_back(ed_row, &m_rset_root);
  }
}


bool Protocol_local::store_null()
{
  if (m_current_column == NULL)
    return TRUE; /* prepare_for_resend() failed to allocate memory. */

  memset(m_current_column, 0, sizeof(*m_current_column));
  ++m_current_column;
  return FALSE;
}


bool Protocol_local::store_column(const void *data, size_t length)
{
  if (m_current_column == NULL)
    return TRUE; /* prepare_for_resend() failed to allocate memory. */
  /*
    alloc_root() automatically aligns memory, so we don't need to
    do any extra alignment if we're pointing to, say, an integer.
  */
  m_current_column->str= (char*) memdup_root(&m_rset_root,
                                             data,
                                             length + 1 /* Safety */);
  if (! m_current_column->str)
    return TRUE;
  m_current_column->str[length]= '\0'; /* Safety */
  m_current_column->length= length;
  ++m_current_column;
  return FALSE;
}


bool
Protocol_local::store_string(const char *str, size_t length,
                             const CHARSET_INFO *src_cs,
                             const CHARSET_INFO *dst_cs)
{
  /* Store with conversion */
  uint error_unused;

  if (dst_cs && !my_charset_same(src_cs, dst_cs) &&
      src_cs != &my_charset_bin &&
      dst_cs != &my_charset_bin)
  {
    if (convert->copy(str, length, src_cs, dst_cs, &error_unused))
      return TRUE;
    str= convert->ptr();
    length= convert->length();
  }
  return store_column(str, length);
}


bool Protocol_local::store_tiny(longlong value)
{
  char v= (char) value;
  return store_column(&v, 1);
}


bool Protocol_local::store_short(longlong value)
{
  int16 v= (int16) value;
  return store_column(&v, 2);
}


bool Protocol_local::store_long(longlong value)
{
  int32 v= (int32) value;
  return store_column(&v, 4);
}


bool Protocol_local::store_longlong(longlong value, bool unsigned_flag)
{
  int64 v= (int64) value;
  return store_column(&v, 8);
}


bool Protocol_local::store_decimal(const my_decimal *value)
{
  char buf[DECIMAL_MAX_STR_LENGTH];
  String str(buf, sizeof (buf), &my_charset_bin);
  int rc;

  rc= my_decimal2string(E_DEC_FATAL_ERROR, value, 0, 0, 0, &str);

  if (rc)
    return TRUE;

  return store_column(str.ptr(), str.length());
}


bool Protocol_local::store(const char *str, size_t length,
                           const CHARSET_INFO *src_cs)
{
  const CHARSET_INFO *dst_cs;

  dst_cs= m_connection->m_thd->variables.character_set_results;
  return store_string(str, length, src_cs, dst_cs);
}


bool Protocol_local::store(const char *str, size_t length,
                           const CHARSET_INFO *src_cs,
                           const CHARSET_INFO *dst_cs)
{
  return store_string(str, length, src_cs, dst_cs);
}


/* Store MYSQL_TIME (in binary format) */

bool Protocol_local::store(MYSQL_TIME *time,
                           uint precision __attribute__((unused)))
{
  return store_column(time, sizeof(MYSQL_TIME));
}


bool Protocol_local::store_date(MYSQL_TIME *time)
{
  return store_column(time, sizeof(MYSQL_TIME));
}


bool Protocol_local::store_time(MYSQL_TIME *time,
                                uint precision __attribute__((unused)))
{
  return store_column(time, sizeof(MYSQL_TIME));
}


/* Store a floating point number, as is. */

bool Protocol_local::store(float value, uint32 decimals, String *buffer)
{
  return store_column(&value, sizeof(float));
}


/* Store a double precision number, as is. */

bool Protocol_local::store(double value, uint32 decimals, String *buffer)
{
  return store_column(&value, sizeof (double));
}


/* Store a Field. */

bool Protocol_local::store(Field *field)
{
  if (field->is_null())
    return store_null();
  return field->send_binary(this);
}


bool Protocol_local::send_result_set_metadata(List<Item> *columns, uint)
{
  DBUG_ASSERT(m_rset == 0 && !alloc_root_inited(&m_rset_root));

  init_sql_alloc(&m_rset_root, MEM_ROOT_BLOCK_SIZE, 0);

  if (! (m_rset= new (&m_rset_root) List<Ed_row>))
    return TRUE;

  m_column_count= columns->elements;

  return FALSE;
}


bool Protocol_local::send_out_parameters(List<Item_param> *sp_params)
{
  return FALSE;
}


bool
Protocol_local::send_ok(uint server_status, uint statement_warn_count,
                        ulonglong affected_rows, ulonglong last_insert_id,
                        const char *message)
{
  /*
    Just make sure nothing is sent to the client, we have grabbed
    the status information in the connection diagnostics area.
  */
  return FALSE;
}


bool Protocol_local::send_eof(uint server_status, uint statement_warn_count)
{
  Ed_result_set *ed_result_set;

  DBUG_ASSERT(m_rset);

  opt_add_row_to_rset();
  m_current_row= 0;

  ed_result_set= new (&m_rset_root) Ed_result_set(m_rset, m_column_count,
                                                  &m_rset_root);

  m_rset= NULL;

  if (! ed_result_set)
    return TRUE;

  /* In case of successful allocation memory ownership was transferred. */
  DBUG_ASSERT(!alloc_root_inited(&m_rset_root));

  /*
    Link the created Ed_result_set instance into the list of connection
    result sets. Never fails.
  */
  m_connection->add_result_set(ed_result_set);
  return FALSE;
}


bool
Protocol_local::send_error(uint sql_errno, const char *err_msg, const char*)
{
  /*
    Just make sure that nothing is sent to the client (default
    implementation).
  */
  return FALSE;
}


#ifdef EMBEDDED_LIBRARY
void Protocol_local::remove_last_row()
{ }
#endif