mysql日志管理
mysql的日志分为如下几类:
1.错误日志
1.1记录服务器启动和关闭过程中的信息
1.2记录服务器运行过程中的错误信息.
1.3记录事件调度器运行一个事件时产生的信息.
1.4在从服务器上启动从服务器进程时产生的信息.
| log_error | /usr/local/mysql/data/idc131.err |错误日志位置
| log_warnings | 1 |将警告日志记入错误日志
2.一般查询日志
mysql> show global variables like ‘general%log%‘;
+------------------+----------------------------------+
| Variable_name | Value |
+------------------+----------------------------------+
| general_log | OFF |是否启用一般查询日志
| general_log_file | /usr/local/mysql/data/idc131.log |一般查询日志的位置
+------------------+----------------------------------+
2 rows in set (0.00 sec)
默认值取决于mysqld在启动时是否使用了--general_log的功能,如果定义,则输出位置由--log-output定义,若该值定义为none,则即使启用了该功能,也不记录任何信息.
mysql> show global variables like ‘log‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log | OFF |是否记录所有语句的操作于一般查询日志中,默认关闭,mysql5.6废弃该参数.
+---------------+-------+
1 row in set (0.00 sec)
mysql> show variables like ‘log_output‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_output | FILE |
+---------------+-------+
1 row in set (0.00 sec)
用于定义一般查询日志或慢查询日志的输出方式,有table,file,none,也可以是table和file的组合,用逗号隔开.
默认为table,如果组合中出现none,则其他的设定都失效,无论是否启用日志功能,都将不记录任何日志信息.
3.慢查询日志
mysql> show variables like ‘log_queries_not_using_indexes‘;
+-------------------------------+-------+
| Variable_name | Value |
+-------------------------------+-------+
| log_queries_not_using_indexes | OFF |
+-------------------------------+-------+
1 row in set (0.00 sec)
是否将未使用索引的查询操作记录到慢查询日志中.
mysql> show global variables like ‘long_query%‘;
+-----------------+-----------+
| Variable_name | Value |
+-----------------+-----------+
| long_query_time | 10.000000 |
+-----------------+-----------+
1 row in set (0.01 sec)
超过该值定义的时间长度的查询,均为慢查询语句.
mysql> show global variables like ‘log_slow_queries‘;
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| log_slow_queries | OFF |
+------------------+-------+
1 row in set (0.00 sec)
是否启用慢查询,mysql5.6中该参数修改为slow_query_log.
mysql> show global variables like ‘slow_query%‘;
+---------------------+---------------------------------------+
| Variable_name | Value |
+---------------------+---------------------------------------+
| slow_query_log | OFF |
| slow_query_log_file | /usr/local/mysql/data/idc131-slow.log |
+---------------------+---------------------------------------+
2 rows in set (0.00 sec)
4.二进制日志:记录任何引起或可能引起数据库变化的语句,用于复制或即时点恢复.
mysql> show global variables like ‘log_bin‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin | ON |
+---------------+-------+
1 row in set (0.00 sec)
是否启用二进制日志,如果mysqld设置了--log_bin选项,则值默认为on,否则为off.
mysql> show global variables like ‘binlog_format‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| binlog_format | MIXED |
+---------------+-------+
1 row in set (0.00 sec)
二进制日志的格式,有row,statement,mixed,默认为statement,若设置该值,但未启用二进制日志,则启动过程中会产生警告信息.
mysql> show global variables like ‘expir%‘;
+------------------+-------+
| Variable_name | Value |
+------------------+-------+
| expire_logs_days | 0 |
+------------------+-------+
1 row in set (0.00 sec)
设定二进制日志的过期天数,超出此天数的二进制日志将被自动删除.
默认为0,表示不启用自动删除功能,如果启动,作用范围发生在mysql启动或flush日志的时候,作用范围是全局.
mysql> show global variables like ‘log_bin_trust_function_creators‘;
+---------------------------------+-------+
| Variable_name | Value |
+---------------------------------+-------+
| log_bin_trust_function_creators | OFF |
+---------------------------------+-------+
1 row in set (0.00 sec)
该参数仅在启用二进制日志时有效,用于控制创建存储函数时,如果会导致不安全的日志记录二进制日志,是否禁止创建存储函数.
默认为0,表示用户除了具有create routine和alter routine权限外,还应该具有super权限,否则将禁止创建存储函数.
还要求在创建函数时必须为其使用deterministic属性,再不然就是附带read sql data或no sql属性.
其值为1时,不启用这些限制.
mysql> show global variables like ‘max_binlog_size‘;
+-----------------+------------+
| Variable_name | Value |
+-----------------+------------+
| max_binlog_size | 1073741824 |
+-----------------+------------+
1 row in set (0.00 sec)
二进制日志文件的上限,单位为字节,最小为4k,最大为1G,默认为1G.
某事物产生的日志仅能写入一个二进制日志文件.因此,实际上的二进制日志可能
mysql> show global variables like ‘max_binlog_cache%‘;
+-----------------------+----------------------+
| Variable_name | Value |
+-----------------------+----------------------+
| max_binlog_cache_size | 18446744073709547520 |
+-----------------------+----------------------+
1 row in set (0.00 sec)
二进制日志缓存空间大小,5.5.9后的版本中仅应用为事物缓存,其上限由max_binlog_stmt_cache_size决定.
mysql> show global variables like ‘max_binlog_stmt%‘;
+----------------------------+----------------------+
| Variable_name | Value |
+----------------------------+----------------------+
| max_binlog_stmt_cache_size | 18446744073709547520 |
+----------------------------+----------------------+
1 row in set (0.00 sec)
mysql> show global variables like ‘sql_log%‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sql_log_bin | ON |是否将二进制日志的信息记录到日志文件.
| sql_log_off | OFF |是否禁止一般查询类的信息记录到查询日志文件,默认不禁止.
+---------------+-------+
2 rows in set (0.00 sec)
mysql> show global variables like ‘sync_binlog%‘;
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| sync_binlog | 0 |
+---------------+-------+
1 row in set (0.00 sec)
设置多久同步一次二进制日志到磁盘中,0表示不同步,N表示对二进制日志每多少次写操作后,同步一次.
当autocommit为1的时候,每条语句执行都会引起日志同步,否则每个事务的提交都会引起日志同步.
二进制日志事件由产生时间和事件相对位置来确定.
二进制日志由索引文件盒二进制日志组成,即由mysql-bin.00000N和mysql-bin.index文件组成.
查看当前正在使用的二进制日志文件:
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000014 | 107 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
查看从二进制日志文件中的事件信息:
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000014 | 107 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
mysql> create table mytab5 select * from mytab1;
Query OK, 6 rows affected (0.28 sec)
Records: 6 Duplicates: 0 Warnings: 0
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000014 | 210 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
mysql> show binlog events in ‘mysql-bin.000014‘;
+------------------+-----+-------------+-----------+-------------+------------------------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+-------------+-----------+-------------+------------------------------------------------------+
| mysql-bin.000014 | 4 | Format_desc | 1 | 107 | Server ver: 5.5.38-log, Binlog ver: 4 |
| mysql-bin.000014 | 107 | Query | 1 | 210 | use `mydb`; create table mytab5 select * from mytab1 |
+------------------+-----+-------------+-----------+-------------+------------------------------------------------------+
2 rows in set (0.00 sec)
mysql> show binlog events in ‘mysql-bin.000014‘ from 107;
+------------------+-----+------------+-----------+-------------+------------------------------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+------------+-----------+-------------+------------------------------------------------------+
| mysql-bin.000014 | 107 | Query | 1 | 210 | use `mydb`; create table mytab5 select * from mytab1 |
+------------------+-----+------------+-----------+-------------+------------------------------------------------------+
1 row in set (0.00 sec)
mysql> help show binlog events;
Name: ‘SHOW BINLOG EVENTS‘
Description:
Syntax:
SHOW BINLOG EVENTS
[IN ‘log_name‘] [FROM pos] [LIMIT [offset,] row_count]
Shows the events in the binary log. If you do not specify ‘log_name‘,
the first binary log is displayed.
URL: http://dev.mysql.com/doc/refman/5.5/en/show-binlog-events.html
显示mysql-bin.000014二进制文件中107位置后面的3个偏移事件:
mysql> show binlog events in ‘mysql-bin.000014‘ from 107 limit 1,3;
+------------------+-----+------------+-----------+-------------+--------------------------------+
| Log_name | Pos | Event_type | Server_id | End_log_pos | Info |
+------------------+-----+------------+-----------+-------------+--------------------------------+
| mysql-bin.000014 | 210 | Query | 1 | 278 | BEGIN |
| mysql-bin.000014 | 278 | Table_map | 1 | 330 | table_id: 33 (mydb.mytab1) |
| mysql-bin.000014 | 330 | Write_rows | 1 | 385 | table_id: 33 flags: STMT_END_F |
+------------------+-----+------------+-----------+-------------+--------------------------------+
3 rows in set (0.00 sec)
使用mysqlbinlog命令显示mysql-bin.000014中的所有信息:
[root@idc131 data]# mysqlbinlog mysql-bin.000014
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#140803 23:15:16 server id 1 end_log_pos 107 Start: binlog v 4, server v 5.5.38-log created 140803 23:15:16 at startup
# Warning: this binlog is either in use or was not closed properly.
ROLLBACK/*!*/;
BINLOG ‘
BFLeUw8BAAAAZwAAAGsAAAABAAQANS41LjM4LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAEUt5TEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA==
‘/*!*/;
# at 107
#140807 6:08:30 server id 1 end_log_pos 210 Query thread_id=24 exec_time=0 error_code=0
use `mydb`/*!*/;
SET TIMESTAMP=1407362910/*!*/;
SET @@session.pseudo_thread_id=24/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=0/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C gbk *//*!*/;
SET @@session.character_set_client=28,@@session.collation_connection=28,@@session.collation_server=33/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
create table mytab5 select * from mytab1
/*!*/;
# at 210
#140807 6:13:36 server id 1 end_log_pos 278 Query thread_id=24 exec_time=0 error_code=0
SET TIMESTAMP=1407363216/*!*/;
BEGIN
/*!*/;
# at 278
# at 330
#140807 6:13:36 server id 1 end_log_pos 330 Table_map: `mydb`.`mytab1` mapped to number 33
#140807 6:13:36 server id 1 end_log_pos 385 Write_rows: table id 33 flags: STMT_END_F
BINLOG ‘
kKjiUxMBAAAANAAAAEoBAAAAACEAAAAAAAEABG15ZGIABm15dGFiMQAEAw8PAQQ8ADwAAA==
kKjiUxcBAAAANwAAAIEBAAAAACEAAAAAAAEABP/wCAAAAANCQkICQjEC8AkAAAADQ0NCAkMxAw==
‘/*!*/;
# at 385
#140807 6:13:36 server id 1 end_log_pos 412 Xid = 59
COMMIT/*!*/;
# at 412
#140807 6:13:45 server id 1 end_log_pos 480 Query thread_id=24 exec_time=0 error_code=0
SET TIMESTAMP=1407363225/*!*/;
BEGIN
/*!*/;
# at 480
# at 532
#140807 6:13:45 server id 1 end_log_pos 532 Table_map: `mydb`.`mytab1` mapped to number 33
#140807 6:13:45 server id 1 end_log_pos 587 Write_rows: table id 33 flags: STMT_END_F
BINLOG ‘
majiUxMBAAAANAAAABQCAAAAACEAAAAAAAEABG15ZGIABm15dGFiMQAEAw8PAQQ8ADwAAA==
majiUxcBAAAANwAAAEsCAAAAACEAAAAAAAEABP/wCwAAAANFRUUCRTEF8AwAAAADRkZGAkY1Bg==
‘/*!*/;
# at 587
#140807 6:13:45 server id 1 end_log_pos 614 Xid = 60
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
使用mysqlbinlog获取mysql-bin.000014中从587到826的日志信息:
[root@idc131 data]# mysqlbinlog --start-position=587 --stop-position=826 mysql-bin.000014
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#140803 23:15:16 server id 1 end_log_pos 107 Start: binlog v 4, server v 5.5.38-log created 140803 23:15:16 at startup
# Warning: this binlog is either in use or was not closed properly.
ROLLBACK/*!*/;
BINLOG ‘
BFLeUw8BAAAAZwAAAGsAAAABAAQANS41LjM4LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAEUt5TEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA==
‘/*!*/;
# at 587
#140807 6:13:45 server id 1 end_log_pos 614 Xid = 60
COMMIT/*!*/;
# at 614
#140807 6:33:04 server id 1 end_log_pos 682 Query thread_id=25 exec_time=0 error_code=0
SET TIMESTAMP=1407364384/*!*/;
SET @@session.pseudo_thread_id=25/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=0/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C gbk *//*!*/;
SET @@session.character_set_client=28,@@session.collation_connection=28,@@session.collation_server=33/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at 682
#140807 6:33:04 server id 1 end_log_pos 710 Intvar
SET INSERT_ID=14/*!*/;
# at 710
#140807 6:33:04 server id 1 end_log_pos 826 Query thread_id=25 exec_time=0 error_code=0
use `mydb`/*!*/;
SET TIMESTAMP=1407364384/*!*/;
insert into mytab1(name,class,age)values(‘UU‘,‘U1‘,8)
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
[root@idc131 data]#
使用mysqlbinlog显示2个时间段间的日志信息:
[root@idc131 data]# mysqlbinlog --start-datetime=‘2014-08-07 06:33:15‘ --stop-datetime=‘2014-08-07 06:33:18‘ mysql-bin.000014
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=1*/;
/*!40019 SET @@session.max_insert_delayed_threads=0*/;
/*!50003 SET @OLD_COMPLETION_TYPE=@@COMPLETION_TYPE,COMPLETION_TYPE=0*/;
DELIMITER /*!*/;
# at 4
#140803 23:15:16 server id 1 end_log_pos 107 Start: binlog v 4, server v 5.5.38-log created 140803 23:15:16 at startup
# Warning: this binlog is either in use or was not closed properly.
ROLLBACK/*!*/;
BINLOG ‘
BFLeUw8BAAAAZwAAAGsAAAABAAQANS41LjM4LWxvZwAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAEUt5TEzgNAAgAEgAEBAQEEgAAVAAEGggAAAAICAgCAA==
‘/*!*/;
# at 853
#140807 6:33:16 server id 1 end_log_pos 921 Query thread_id=25 exec_time=0 error_code=0
SET TIMESTAMP=1407364396/*!*/;
SET @@session.pseudo_thread_id=25/*!*/;
SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1/*!*/;
SET @@session.sql_mode=0/*!*/;
SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/;
/*!\C gbk *//*!*/;
SET @@session.character_set_client=28,@@session.collation_connection=28,@@session.collation_server=33/*!*/;
SET @@session.lc_time_names=0/*!*/;
SET @@session.collation_database=DEFAULT/*!*/;
BEGIN
/*!*/;
# at 921
#140807 6:33:16 server id 1 end_log_pos 949 Intvar
SET INSERT_ID=15/*!*/;
# at 949
#140807 6:33:16 server id 1 end_log_pos 1066 Query thread_id=25 exec_time=0 error_code=0
use `mydb`/*!*/;
SET TIMESTAMP=1407364396/*!*/;
insert into mytab1(name,class,age)values(‘OO‘,‘U2‘,88)
/*!*/;
# at 1066
#140807 6:33:16 server id 1 end_log_pos 1093 Xid = 77
COMMIT/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;
/*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
[root@idc131 data]#
滚动二进制日志:
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000014 | 1093 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
mysql> flush logs;
Query OK, 0 rows affected (0.20 sec)
mysql> show master status;
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000015 | 107 | | |
+------------------+----------+--------------+------------------+
1 row in set (0.00 sec)
重启mysql后,自动滚动日志.
[root@idc131 ~]# mysql -e ‘show master status‘
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000015 | 107 | | |
+------------------+----------+--------------+------------------+
[root@idc131 ~]# service mysqld restart
Shutting down MySQL. SUCCESS!
Starting MySQL... SUCCESS!
[root@idc131 ~]# mysql -e ‘show master status‘
+------------------+----------+--------------+------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000016 | 107 | | |
+------------------+----------+--------------+------------------+
清理二进制日志方法:
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000001 | 107 |
| mysql-bin.000002 | 107 |
| mysql-bin.000003 | 27690 |
| mysql-bin.000004 | 1070318 |
| mysql-bin.000005 | 301 |
| mysql-bin.000006 | 1345 |
| mysql-bin.000007 | 126 |
| mysql-bin.000008 | 4063 |
| mysql-bin.000009 | 3787 |
| mysql-bin.000010 | 362 |
| mysql-bin.000011 | 126 |
| mysql-bin.000012 | 126 |
| mysql-bin.000013 | 126 |
| mysql-bin.000014 | 1136 |
| mysql-bin.000015 | 126 |
| mysql-bin.000016 | 107 |
+------------------+-----------+
16 rows in set (0.00 sec)
mysql> purge binary logs to ‘mysql-bin.000003‘;
Query OK, 0 rows affected (0.03 sec)
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000003 | 27690 |
| mysql-bin.000004 | 1070318 |
| mysql-bin.000005 | 301 |
| mysql-bin.000006 | 1345 |
| mysql-bin.000007 | 126 |
| mysql-bin.000008 | 4063 |
| mysql-bin.000009 | 3787 |
| mysql-bin.000010 | 362 |
| mysql-bin.000011 | 126 |
| mysql-bin.000012 | 126 |
| mysql-bin.000013 | 126 |
| mysql-bin.000014 | 1136 |
| mysql-bin.000015 | 126 |
| mysql-bin.000016 | 107 |
+------------------+-----------+
14 rows in set (0.00 sec)
mysql> purge binary logs before ‘20140806‘;
Query OK, 0 rows affected (0.08 sec)
mysql> show binary logs;
+------------------+-----------+
| Log_name | File_size |
+------------------+-----------+
| mysql-bin.000014 | 1136 |
| mysql-bin.000015 | 126 |
| mysql-bin.000016 | 107 |
+------------------+-----------+
3 rows in set (0.00 sec)
log_bin和sql_log_bin决定了是否写二进制日志.
sql_log_off该参数决定了是否将一般查询日志写入查询日志文件.
5.中继日志:
mysql> show variables like ‘log_slave_updates‘;
+-------------------+-------+
| Variable_name | Value |
+-------------------+-------+
| log_slave_updates | OFF |
+-------------------+-------+
1 row in set (0.00 sec)
用于是否将主服务器同步过来的操作记录到二进制日志中.
mysql> show global variables like ‘relay_log%‘;
+-----------------------+----------------+
| Variable_name | Value |
+-----------------------+----------------+
| relay_log | |中继日志文件名
| relay_log_index | |中继日志索引文件名
| relay_log_info_file | relay-log.info |
| relay_log_purge | ON |对不再需要的中继日志是否自动清理.
| relay_log_recovery | OFF |
| relay_log_space_limit | 0 |设置存储中继日志的可用空间大小.
+-----------------------+----------------+
6 rows in set (0.00 sec)
6.事务日志
事务性存储引擎用来保证事务的ACID特性的,相当于oracle中的undo.
mysql> show variables like ‘innodb_flush_log_at_trx_commit‘;
+--------------------------------+-------+
| Variable_name | Value |
+--------------------------------+-------+
| innodb_flush_log_at_trx_commit | 1 |
+--------------------------------+-------+
1 row in set (0.00 sec)
0表示每秒刷新,并执行磁盘flush操作.
1表示每事务刷写,并执行磁盘flush操作.
2表示每事务同步,但不执行磁盘flush.
mysql> show variables like ‘innodb_log_file%‘;
+---------------------------+---------+
| Variable_name | Value |
+---------------------------+---------+
| innodb_log_file_size | 5242880 |事务日志文件大小
| innodb_log_files_in_group | 2 |事务日志组中的文件个数.
+---------------------------+---------+
2 rows in set (0.00 sec)
mysql> show variables like ‘innodb_mirror%‘;
+----------------------------+-------+
| Variable_name | Value |
+----------------------------+-------+
| innodb_mirrored_log_groups | 1 |事务日志镜像组的个数.
+----------------------------+-------+
1 row in set (0.00 sec)
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原文地址：http://webseven.blog.51cto.com/4388012/1537810
