1
/* Copyright (C) 2000-2003 MySQL AB
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.
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.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
20
@defgroup Replication Replication
25
#ifdef HAVE_REPLICATION
29
#include "rpl_filter.h"
30
#include "rpl_tblmap.h"
32
#define SLAVE_NET_TIMEOUT 3600
34
#define MAX_SLAVE_ERROR 2000
37
// Forward declarations
42
/*****************************************************************************
46
Replication is implemented via two types of threads:
48
I/O Thread - One of these threads is started for each master server.
49
They maintain a connection to their master server, read log
50
events from the master as they arrive, and queues them into
51
a single, shared relay log file. A Master_info
52
represents each of these threads.
54
SQL Thread - One of these threads is started and reads from the relay log
55
file, executing each event. A Relay_log_info
56
represents this thread.
58
Buffering in the relay log file makes it unnecessary to reread events from
59
a master server across a slave restart. It also decouples the slave from
60
the master where long-running updates and event logging are concerned--ie
61
it can continue to log new events while a slow query executes on the slave.
63
*****************************************************************************/
66
MUTEXES in replication:
68
LOCK_active_mi: [note: this was originally meant for multimaster, to switch
69
from a master to another, to protect active_mi] It is used to SERIALIZE ALL
70
administrative commands of replication: START SLAVE, STOP SLAVE, CHANGE
71
MASTER, RESET SLAVE, end_slave() (when mysqld stops) [init_slave() does not
72
need it it's called early]. Any of these commands holds the mutex from the
73
start till the end. This thus protects us against a handful of deadlocks
74
(consider start_slave_thread() which, when starting the I/O thread, releases
75
mi->run_lock, keeps rli->run_lock, and tries to re-acquire mi->run_lock).
77
Currently active_mi never moves (it's created at startup and deleted at
78
shutdown, and not changed: it always points to the same Master_info struct),
79
because we don't have multimaster. So for the moment, mi does not move, and
80
mi->rli does not either.
82
In Master_info: run_lock, data_lock
83
run_lock protects all information about the run state: slave_running, thd
84
and the existence of the I/O thread to stop/start it, you need this mutex).
85
data_lock protects some moving members of the struct: counters (log name,
86
position) and relay log (MYSQL_BIN_LOG object).
88
In Relay_log_info: run_lock, data_lock
91
Order of acquisition: if you want to have LOCK_active_mi and a run_lock, you
92
must acquire LOCK_active_mi first.
94
In MYSQL_BIN_LOG: LOCK_log, LOCK_index of the binlog and the relay log
95
LOCK_log: when you write to it. LOCK_index: when you create/delete a binlog
96
(so that you have to update the .index file).
99
extern ulong master_retry_count;
100
extern MY_BITMAP slave_error_mask;
101
extern char slave_skip_error_names[];
102
extern bool use_slave_mask;
103
extern char *slave_load_tmpdir;
104
extern char *master_info_file, *relay_log_info_file;
105
extern char *opt_relay_logname, *opt_relaylog_index_name;
106
extern my_bool opt_skip_slave_start, opt_reckless_slave;
107
extern my_bool opt_log_slave_updates;
108
extern ulonglong relay_log_space_limit;
111
3 possible values for Master_info::slave_running and
112
Relay_log_info::slave_running.
113
The values 0,1,2 are very important: to keep the diff small, I didn't
114
substitute places where we use 0/1 with the newly defined symbols. So don't change
116
The same way, code is assuming that in Relay_log_info we use only values
118
I started with using an enum, but
119
enum_variable=1; is not legal so would have required many line changes.
121
#define MYSQL_SLAVE_NOT_RUN 0
122
#define MYSQL_SLAVE_RUN_NOT_CONNECT 1
123
#define MYSQL_SLAVE_RUN_CONNECT 2
125
#define RPL_LOG_NAME (rli->group_master_log_name[0] ? rli->group_master_log_name :\
127
#define IO_RPL_LOG_NAME (mi->master_log_name[0] ? mi->master_log_name :\
131
If the following is set, if first gives an error, second will be
132
tried. Otherwise, if first fails, we fail.
134
#define SLAVE_FORCE_ALL 4
137
void init_slave_skip_errors(const char* arg);
138
bool flush_relay_log_info(Relay_log_info* rli);
139
int register_slave_on_master(MYSQL* mysql);
140
int terminate_slave_threads(Master_info* mi, int thread_mask,
142
int start_slave_threads(bool need_slave_mutex, bool wait_for_start,
143
Master_info* mi, const char* master_info_fname,
144
const char* slave_info_fname, int thread_mask);
146
cond_lock is usually same as start_lock. It is needed for the case when
147
start_lock is 0 which happens if start_slave_thread() is called already
148
inside the start_lock section, but at the same time we want a
149
pthread_cond_wait() on start_cond,start_lock
151
int start_slave_thread(pthread_handler h_func, pthread_mutex_t* start_lock,
152
pthread_mutex_t *cond_lock,
153
pthread_cond_t* start_cond,
154
volatile uint *slave_running,
155
volatile ulong *slave_run_id,
159
/* If fd is -1, dump to NET */
160
int mysql_table_dump(THD* thd, const char* db,
161
const char* tbl_name, int fd = -1);
163
/* retrieve table from master and copy to slave*/
164
int fetch_master_table(THD* thd, const char* db_name, const char* table_name,
165
Master_info* mi, MYSQL* mysql, bool overwrite);
167
bool show_master_info(THD* thd, Master_info* mi);
168
bool show_binlog_info(THD* thd);
169
bool rpl_master_has_bug(const Relay_log_info *rli, uint bug_id, bool report,
170
bool (*pred)(const void *), const void *param);
171
bool rpl_master_erroneous_autoinc(THD* thd);
173
const char *print_slave_db_safe(const char *db);
174
void skip_load_data_infile(NET* net);
176
void end_slave(); /* release slave threads */
177
void close_active_mi(); /* clean up slave threads data */
178
void clear_until_condition(Relay_log_info* rli);
179
void clear_slave_error(Relay_log_info* rli);
180
void end_relay_log_info(Relay_log_info* rli);
181
void lock_slave_threads(Master_info* mi);
182
void unlock_slave_threads(Master_info* mi);
183
void init_thread_mask(int* mask,Master_info* mi,bool inverse);
184
int init_relay_log_pos(Relay_log_info* rli,const char* log,ulonglong pos,
185
bool need_data_lock, const char** errmsg,
186
bool look_for_description_event);
188
int purge_relay_logs(Relay_log_info* rli, THD *thd, bool just_reset,
189
const char** errmsg);
190
void set_slave_thread_options(THD* thd);
191
void set_slave_thread_default_charset(THD *thd, Relay_log_info const *rli);
192
void rotate_relay_log(Master_info* mi);
193
int apply_event_and_update_pos(Log_event* ev, THD* thd, Relay_log_info* rli);
195
pthread_handler_t handle_slave_io(void *arg);
196
pthread_handler_t handle_slave_sql(void *arg);
197
extern bool volatile abort_loop;
198
extern Master_info main_mi, *active_mi; /* active_mi for multi-master */
199
extern LIST master_list;
200
extern my_bool replicate_same_server_id;
202
extern int disconnect_slave_event_count, abort_slave_event_count ;
204
/* the master variables are defaults read from my.cnf or command line */
205
extern uint master_port, master_connect_retry, report_port;
206
extern char * master_user, *master_password, *master_host;
207
extern char *master_info_file, *relay_log_info_file, *report_user;
208
extern char *report_host, *report_password;
210
extern my_bool master_ssl;
211
extern char *master_ssl_ca, *master_ssl_capath, *master_ssl_cert;
212
extern char *master_ssl_cipher, *master_ssl_key;
214
extern I_List<THD> threads;
216
#endif /* HAVE_REPLICATION */
218
/* masks for start/stop operations on io and sql slave threads */
223
@} (end of group Replication)