1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/* Copyright (C) 2000 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/* For use with thr_lock:s */
#ifndef _thr_lock_h
#define _thr_lock_h
#ifdef __cplusplus
extern "C" {
#endif
#include <my_pthread.h>
#include <my_list.h>
struct st_thr_lock;
extern ulong locks_immediate,locks_waited ;
enum thr_lock_type { TL_IGNORE=-1,
TL_UNLOCK, /* UNLOCK ANY LOCK */
TL_READ, /* Read lock */
TL_READ_WITH_SHARED_LOCKS,
/* High prior. than TL_WRITE. Allow concurrent insert */
TL_READ_HIGH_PRIORITY,
/* READ, Don't allow concurrent insert */
TL_READ_NO_INSERT,
/*
Write lock, but allow other threads to read / write.
Used by BDB tables in MySQL to mark that someone is
reading/writing to the table.
*/
TL_WRITE_ALLOW_WRITE,
/*
Write lock, but allow other threads to read.
Used by ALTER TABLE in MySQL to allow readers
to use the table until ALTER TABLE is finished.
*/
TL_WRITE_ALLOW_READ,
/*
WRITE lock used by concurrent insert. Will allow
READ, if one could use concurrent insert on table.
*/
TL_WRITE_CONCURRENT_INSERT,
/* Write used by INSERT DELAYED. Allows READ locks */
TL_WRITE_DELAYED,
/* WRITE lock that has lower priority than TL_READ */
TL_WRITE_LOW_PRIORITY,
/* Normal WRITE lock */
TL_WRITE,
/* Abort new lock request with an error */
TL_WRITE_ONLY};
enum enum_thr_lock_result { THR_LOCK_SUCCESS= 0, THR_LOCK_ABORTED= 1,
THR_LOCK_WAIT_TIMEOUT= 2, THR_LOCK_DEADLOCK= 3 };
extern ulong max_write_lock_count;
extern ulong table_lock_wait_timeout;
extern my_bool thr_lock_inited;
extern enum thr_lock_type thr_upgraded_concurrent_insert_lock;
/*
A description of the thread which owns the lock. The address
of an instance of this structure is used to uniquely identify the thread.
*/
typedef struct st_thr_lock_info
{
pthread_t thread;
ulong thread_id;
ulong n_cursors;
} THR_LOCK_INFO;
/*
Lock owner identifier. Globally identifies the lock owner within the
thread and among all the threads. The address of an instance of this
structure is used as id.
*/
typedef struct st_thr_lock_owner
{
THR_LOCK_INFO *info;
} THR_LOCK_OWNER;
typedef struct st_thr_lock_data {
THR_LOCK_OWNER *owner;
struct st_thr_lock_data *next,**prev;
struct st_thr_lock *lock;
pthread_cond_t *cond;
enum thr_lock_type type;
void *status_param; /* Param to status functions */
void *debug_print_param;
} THR_LOCK_DATA;
struct st_lock_list {
THR_LOCK_DATA *data,**last;
};
typedef struct st_thr_lock {
LIST list;
pthread_mutex_t mutex;
struct st_lock_list read_wait;
struct st_lock_list read;
struct st_lock_list write_wait;
struct st_lock_list write;
/* write_lock_count is incremented for write locks and reset on read locks */
ulong write_lock_count;
uint read_no_write_count;
void (*get_status)(void*, int); /* When one gets a lock */
void (*copy_status)(void*,void*);
void (*update_status)(void*); /* Before release of write */
my_bool (*check_status)(void *);
} THR_LOCK;
extern LIST *thr_lock_thread_list;
extern pthread_mutex_t THR_LOCK_lock;
my_bool init_thr_lock(void); /* Must be called once/thread */
#define thr_lock_owner_init(owner, info_arg) (owner)->info= (info_arg)
void thr_lock_info_init(THR_LOCK_INFO *info);
void thr_lock_init(THR_LOCK *lock);
void thr_lock_delete(THR_LOCK *lock);
void thr_lock_data_init(THR_LOCK *lock,THR_LOCK_DATA *data,
void *status_param);
enum enum_thr_lock_result thr_lock(THR_LOCK_DATA *data,
THR_LOCK_OWNER *owner,
enum thr_lock_type lock_type);
void thr_unlock(THR_LOCK_DATA *data);
enum enum_thr_lock_result thr_multi_lock(THR_LOCK_DATA **data,
uint count, THR_LOCK_OWNER *owner);
void thr_multi_unlock(THR_LOCK_DATA **data,uint count);
void thr_abort_locks(THR_LOCK *lock, bool upgrade_lock);
my_bool thr_abort_locks_for_thread(THR_LOCK *lock, pthread_t thread);
void thr_print_locks(void); /* For debugging */
my_bool thr_upgrade_write_delay_lock(THR_LOCK_DATA *data);
void thr_downgrade_write_lock(THR_LOCK_DATA *data,
enum thr_lock_type new_lock_type);
my_bool thr_reschedule_write_lock(THR_LOCK_DATA *data);
#ifdef __cplusplus
}
#endif
#endif /* _thr_lock_h */