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thr_lock.h
1 /* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
2 
3  This program is free software; you can redistribute it and/or modify
4  it under the terms of the GNU General Public License as published by
5  the Free Software Foundation; version 2 of the License.
6 
7  This program is distributed in the hope that it will be useful,
8  but WITHOUT ANY WARRANTY; without even the implied warranty of
9  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10  GNU General Public License for more details.
11 
12  You should have received a copy of the GNU General Public License
13  along with this program; if not, write to the Free Software
14  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
15 
16 /* For use with thr_lock:s */
17 
18 #ifndef _thr_lock_h
19 #define _thr_lock_h
20 #ifdef __cplusplus
21 extern "C" {
22 #endif
23 
24 #include <my_pthread.h>
25 #include <my_list.h>
26 
27 struct st_thr_lock;
28 extern ulong locks_immediate,locks_waited ;
29 
30 /*
31  Important: if a new lock type is added, a matching lock description
32  must be added to sql_test.cc's lock_descriptions array.
33 */
34 enum thr_lock_type { TL_IGNORE=-1,
35  TL_UNLOCK, /* UNLOCK ANY LOCK */
36  /*
37  Parser only! At open_tables() becomes TL_READ or
38  TL_READ_NO_INSERT depending on the binary log format
39  (SBR/RBR) and on the table category (log table).
40  Used for tables that are read by statements which
41  modify tables.
42  */
43  TL_READ_DEFAULT,
44  TL_READ, /* Read lock */
45  TL_READ_WITH_SHARED_LOCKS,
46  /* High prior. than TL_WRITE. Allow concurrent insert */
47  TL_READ_HIGH_PRIORITY,
48  /* READ, Don't allow concurrent insert */
49  TL_READ_NO_INSERT,
50  /*
51  Write lock, but allow other threads to read / write.
52  Used by BDB tables in MySQL to mark that someone is
53  reading/writing to the table.
54  */
55  TL_WRITE_ALLOW_WRITE,
56  /*
57  WRITE lock used by concurrent insert. Will allow
58  READ, if one could use concurrent insert on table.
59  */
60  TL_WRITE_CONCURRENT_INSERT,
61  /* Write used by INSERT DELAYED. Allows READ locks */
62  TL_WRITE_DELAYED,
63  /*
64  parser only! Late bound low_priority flag.
65  At open_tables() becomes thd->update_lock_default.
66  */
67  TL_WRITE_DEFAULT,
68  /* WRITE lock that has lower priority than TL_READ */
69  TL_WRITE_LOW_PRIORITY,
70  /* Normal WRITE lock */
71  TL_WRITE,
72  /* Abort new lock request with an error */
73  TL_WRITE_ONLY};
74 
75 enum enum_thr_lock_result { THR_LOCK_SUCCESS= 0, THR_LOCK_ABORTED= 1,
76  THR_LOCK_WAIT_TIMEOUT= 2, THR_LOCK_DEADLOCK= 3 };
77 
78 
79 extern ulong max_write_lock_count;
80 extern my_bool thr_lock_inited;
81 extern enum thr_lock_type thr_upgraded_concurrent_insert_lock;
82 
83 /*
84  A description of the thread which owns the lock. The address
85  of an instance of this structure is used to uniquely identify the thread.
86 */
87 
88 typedef struct st_thr_lock_info
89 {
90  pthread_t thread;
91  my_thread_id thread_id;
92 } THR_LOCK_INFO;
93 
94 
95 typedef struct st_thr_lock_data {
96  THR_LOCK_INFO *owner;
97  struct st_thr_lock_data *next,**prev;
98  struct st_thr_lock *lock;
99  mysql_cond_t *cond;
100  enum thr_lock_type type;
101  void *status_param; /* Param to status functions */
102  void *debug_print_param;
103  struct PSI_table *m_psi;
104 } THR_LOCK_DATA;
105 
106 struct st_lock_list {
107  THR_LOCK_DATA *data,**last;
108 };
109 
110 typedef struct st_thr_lock {
111  LIST list;
112  mysql_mutex_t mutex;
113  struct st_lock_list read_wait;
114  struct st_lock_list read;
115  struct st_lock_list write_wait;
116  struct st_lock_list write;
117  /* write_lock_count is incremented for write locks and reset on read locks */
118  ulong write_lock_count;
119  uint read_no_write_count;
120  void (*get_status)(void*, int); /* When one gets a lock */
121  void (*copy_status)(void*,void*);
122  void (*update_status)(void*); /* Before release of write */
123  void (*restore_status)(void*); /* Before release of read */
124  my_bool (*check_status)(void *);
125 } THR_LOCK;
126 
127 
128 extern LIST *thr_lock_thread_list;
129 extern mysql_mutex_t THR_LOCK_lock;
130 
131 my_bool init_thr_lock(void); /* Must be called once/thread */
132 void thr_lock_info_init(THR_LOCK_INFO *info);
133 void thr_lock_init(THR_LOCK *lock);
134 void thr_lock_delete(THR_LOCK *lock);
135 void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data,
136  void *status_param);
137 enum enum_thr_lock_result thr_lock(THR_LOCK_DATA *data,
138  THR_LOCK_INFO *owner,
139  enum thr_lock_type lock_type,
140  ulong lock_wait_timeout);
141 void thr_unlock(THR_LOCK_DATA *data);
142 enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
143  uint count, THR_LOCK_INFO *owner,
144  ulong lock_wait_timeout);
145 void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
146 void
147 thr_lock_merge_status(THR_LOCK_DATA **data, uint count);
148 void thr_abort_locks(THR_LOCK *lock, my_bool upgrade_lock);
149 my_bool thr_abort_locks_for_thread(THR_LOCK *lock, my_thread_id thread);
150 void thr_print_locks(void); /* For debugging */
151 my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data,
152  enum thr_lock_type new_lock_type,
153  ulong lock_wait_timeout);
154 void thr_downgrade_write_lock(THR_LOCK_DATA *data,
155  enum thr_lock_type new_lock_type);
156 my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data,
157  ulong lock_wait_timeout);
158 void thr_set_lock_wait_callback(void (*before_wait)(void),
159  void (*after_wait)(void));
160 #ifdef __cplusplus
161 }
162 #endif
163 #endif /* _thr_lock_h */