日志文件记录了MySQL数据库的各种类型的活动,MySQL数据库中常见的日志文件有 查询日志,慢查询日志,错误日志,二进制日志,中继日志 ,事务日志。
修改配置或者想要使配置永久生效需将内容写入配置文件中:/etc/my.cnf.d/server.cnf
一、查询日志
查询日志在mysql中称为general log(通用日志),查询日志记录了数据库执行的命令,不管这些语句是否正确,都会被记录。由于数据库操作命令有可能非常多而且执行比较频繁,所以开启了查询日志以后,数据库可能需要不停的写入查询日志,这样会增大服务器的IO压力,增加很多系统开销,影响数据库的性能,所以默认情况下是关闭的,也不建议开启。
存储查询日志的方式:
方式1:将查询日志存放于指定的日志文件中;
方式2:将查询日志存放于mysql.general_log表中;
方式3:将查询日志同时存放于指定的日志文件与mysql库的general_log表中。
1、查看查询日志的相关参数
MariaDB [mysql]> show global variables like '%gen%log%'; +------------------+----------+ | Variable_name | Value | +------------------+----------+ | general_log | OFF | | general_log_file | ren7.log | +------------------+----------+ 2 rows in set (0.00 sec) MariaDB [mysql]> show variables where variable_name like '%general_log%' or variable_name='log_output'; +------------------+----------+ | Variable_name | Value | +------------------+----------+ | general_log | OFF | | general_log_file | ren7.log | | log_output | FILE | +------------------+----------+ 3 rows in set (0.00 sec)
2、查询日志变量详解
1 general_log: 指定是否开启查询日志(ON表示开启,OFF表示未开启,默认OFF) 2 general_log_file: 当log_output设置为“FILE”时,指定将查询日志保存成哪个文件、叫什么名,默认与主机名相同,一般位于/var/lib/mysql目录下 3 log_output: 指定将记录到的查询保存到什么位置(“NONE”、“FILE”、“TABLE”、“FILE,TABLE”) 4 file: 保存成一个文件 5 table: 保存成一张表 6 none: 不记录
二、慢查询日志**
慢查询日志用来记录响应时间超过阈值的SQL语句,所以我们可以设置一个阈值,将运行时间超过该值的所有SQL语句都记录到慢查询日志文件中。该阈值可以通过参数 slow_launch_time
来设置,默认为2秒。
1、查看慢查询日志的变量
MariaDB [mysql]> show global variables like '%slow%'; +---------------------------+--------------------------------------------------------------------------------------------------------------+ | Variable_name | Value | +---------------------------+--------------------------------------------------------------------------------------------------------------+ | log_slow_admin_statements | ON | | log_slow_filter | admin,filesort,filesort_on_disk,full_join,full_scan,query_cache,query_cache_miss,tmp_table,tmp_table_on_disk | | log_slow_rate_limit | 1 | | log_slow_slave_statements | ON | | log_slow_verbosity | | | slow_launch_time | 2 | | slow_query_log | OFF | | slow_query_log_file | ren7-slow.log | +---------------------------+--------------------------------------------------------------------------------------------------------------+ 8 rows in set (0.00 sec)
2、变量详解
1 slow_query_log = OFF|ON (0|1) #开启慢查询日志 2 slow_query_log_file = LOCALHOST-SLOW.log #慢查询日志的文件路径 3 long_query_time #慢查询时长;默认是10s 4 log_slow_rate_limit #如果要记录的慢查询日志非常多的话,会按照速率来记录,默认1秒记录一个 5 log_slow_verbosity=full | query_plan #记录的详细级别 6 log_output #指定将记录到的查询保存到什么位置
3、开启慢查询日志及测试
MariaDB [(none)]> set global slow_query_log=on; #当前会话不生效,需重新连接数据库 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> select @@global.slow_query_log; +-------------------------+ | @@global.slow_query_log | +-------------------------+ | 1 | +-------------------------+ 1 row in set (0.00 sec) MariaDB [(none)]> select sleep(15); #测试4次 +-----------+ | sleep(15) | +-----------+ | 0 | +-----------+ 1 row in set (15.00 sec) [root@ren7 mysql]# tailf /var/lib/mysql/ren7-slow.log #查看慢查询日志的文件(默认保存类型是FILE) # Time: 190907 15:47:18 # User@Host: root[root] @ localhost [] # Thread_id: 10 Schema: QC_hit: No # Query_time: 15.008583 Lock_time: 0.000000 Rows_sent: 1 Rows_examined: 0 # Rows_affected: 0 SET timestamp=1567842438; select sleep(15); MariaDB [ren]> show global status like '%slow_queries%'; #查看一共记录了多少条慢查询语句 +---------------+-------+ | Variable_name | Value | +---------------+-------+ | Slow_queries | 4 | +---------------+-------+ 1 row in set (0.00 sec)
4、mysqldumpslow命令
mysqldumpslow是mysql自带的慢查询日志统计分析工具,可以对慢查询日志进行排序、查找、统计(只有我们将log_output的值设置为“FILE”或者“FILE,TABLE”时,mysqldumpslow才可以用)
(1)使用
[root@ren7 ~]# mysqldumpslow -s t /var/lib/mysql/ren7-slow.log Reading mysql slow query log from /var/lib/mysql/ren7-slow.log Count: 4 Time=15.01s (60s) Lock=0.00s (0s) Rows_sent=1.0 (4), Rows_examined=0.0 (0), Rows_affected=0.0 (0), root[root]@localhost select sleep(N)
(2)参数说明
[root@ren7 ~]# mysqldumpslow --help Usage: mysqldumpslow [ OPTS... ] [ LOGS... ] Parse and summarize the MySQL slow query log. Options are --verbose verbose --debug debug --help write this text to standard output -v verbose -d debug -s ORDER what to sort by (aa, ae, al, ar, at, a, c, e, l, r, t), 'at' is default aa: average rows affected ae: aggregated rows examined al: average lock time(平均锁定时间) ar: average rows sent(平均返回记录数) at: average query time(平均执行时间) a: rows affected c: count(执行计数) e: rows examined l: lock time(锁定时间) r: rows sent(返回记录) t: query time(执行时间) -r reverse the sort order (largest last instead of first) -t NUM just show the top n queries(指定只查看多少条统计信息) -a don't abstract all numbers to N and strings to 'S' -n NUM abstract numbers with at least n digits within names -g PATTERN grep: only consider stmts that include this string(正则表达式) -h HOSTNAME hostname of db server for *-slow.log filename (can be wildcard), default is '*', i.e. match all -i NAME name of server instance (if using mysql.server startup script) -l don't subtract lock time from total time
三、错误日志
主要记录:(很重要的信息日志文件)
(1)mysqld启动和关闭过程中输出的事件信息
(2)mysqld运行中产生的错误信息
(3)event scheduler 运行一个event时产生的日志信息
(4)在主从复制架构中的从服务器IO复制线程时产生的信息
1、查看参数
MariaDB [mysql]> show variables like '%log_error%'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_error | | +---------------+-------+ 1 row in set (0.00 sec) MariaDB [mysql]> show variables like '%log_warnings%'; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | log_warnings | 2 | +---------------+-------+ 1 row in set (0.01 sec)
2、参数详解
1 log_error = /var/log/mysql_error.log #指定错误日志的输出位置 2 log_warnings 为0, 表示不记录告警信息。 3 log_warnings 为1, 表示告警信息写入错误日志。 4 log_warnings 大于1, 表示各类告警信息,例如有关网络故障的信息和重新连接信息写入错误日志。(默认为2)
四、二进制日志***
在mysql中二进制日志为binlog,它记录了对数据库执行更改的所有操作,但是不包括 select
和 show
这类操作,因为这类操作对数据本身并没有修改,如果你还想记录select和show操作,那只能使用查询日志了,而不是二进制日志。(增删改的SQL语句)
二进制还包括了执行数据库更改操作的时间和执行时间等信息,它主要用于时间点恢复(备份恢复)以及主从复制结构
- 恢复(recovery) : 某些数据的恢复需要二进制日志,如当一个数据库全备文件恢复后,我们可以通过二进制的日志进行
point-in-time
的恢复 - 复制(replication) : 通过复制和执行二进制日志使得一台远程的 MySQL 数据库(一般是slave 或者 standby) 与一台MySQL数据库(一般为master或者primary) 进行实时同步
- 审计(audit) :用户可以通过二进制日志中的信息来进行审计,判断是否有对数据库进行注入攻击
1、查看变量
MariaDB [mysql]> show global variables like '%bin%'; +-----------------------------------------+--------------------------------+ | Variable_name | Value | +-----------------------------------------+--------------------------------+ | binlog_annotate_row_events | ON | | binlog_cache_size | 32768 | | binlog_checksum | CRC32 | | binlog_commit_wait_count | 0 | | binlog_commit_wait_usec | 100000 | | binlog_direct_non_transactional_updates | OFF | | binlog_format | MIXED | | binlog_optimize_thread_scheduling | ON | | binlog_row_image | FULL | | binlog_stmt_cache_size | 32768 | | encrypt_binlog | OFF | | gtid_binlog_pos | 0-1-1 | | gtid_binlog_state | 0-1-1 | | innodb_locks_unsafe_for_binlog | OFF | | log_bin | ON | | log_bin_basename | /var/lib/mysql/mysql-bin | | log_bin_compress | OFF | | log_bin_compress_min_len | 256 | | log_bin_index | /var/lib/mysql/mysql-bin.index | | log_bin_trust_function_creators | OFF | | max_binlog_cache_size | 18446744073709547520 | | max_binlog_size | 1073741824 | | max_binlog_stmt_cache_size | 18446744073709547520 | | read_binlog_speed_limit | 0 | | sql_log_bin | ON | | sync_binlog | 0 | | wsrep_forced_binlog_format | NONE | +-----------------------------------------+--------------------------------+ 27 rows in set (0.00 sec)
2、变量详解
二进制日志文件的构成:
(1)日志文件:mysql-bin.xxxxxx,二进制格式
(2)索引文件:mysql-bin,index,索引文件(十进制文件)
log_bin = LOG_NAME: (只读变量)只能通过修改配置文件来指定是否启用二进制日志(全局的)
#my.cnf配置文件中没有log_bin的配置,表示未开启二进制日志,如果存在log_bin的配置,则表示开启了二进制日志,同时,二进制日志文件的名称将会以log_bin对应的值为文件名前缀,文件默认位置在/var/lib/mysql/下,二进制日志文件的后缀名会进行自动编号,每次日志滚动后,后缀名编号自动加1. log_bin_basename = /var/lib/mysql/mysql-bin: 指定二进制日志的文件的基名 log_bin_index = /var/lib/mysql/mysql-bin.index:指定二进制日志文件的索引文件 binlog_format = STATEMENT|ROW|MIXED: 指定基于哪种方式进行记录
STATEMENT: 基于“语句”记录
ROW: 基于“行”记录
MIXED: 让系统自行判定该基于哪种方式记录
sync_binlog = 1|0: 设定是否启动二进制日志同步功能 -->每次提交事务,会将缓存中的内存刷新到二进制日志文件中。 -->默认每个sql语句是一个事务,而且默认事务会自动提交,所以,默认的性能很差
-->此值为0时,表示当事务提交后,不会立即将内存中的binlog刷新到磁盘中;安全性最差,性能最高
-->此值为1时,表示每一次事务提交后,都会立即将内存中的二进制文件同步到磁盘中;安全性最高,性能最差
-->还能设置为N,当设置为3时,表示每3次事务提交后,将binlog从内存刷写到磁盘一次,值设置的越大,有可能丢失的日志数据越多,但性能会越好
max_binlog_size = SIZE: 指定二进制日志文件的上限,超过上限会滚动,以字节为单位(默认为1G,为1073741824B) max_binlog_cache_size = SIZE: 指定二进制日志缓存空间大小,空间被填满,会自动滚动 sql_log_off = on|off: 是否将一般的查询操作记录到二进制日志中 sql_log_bin = ON |OFF: 指定是否启用二进制日志(会话级别) log_bin_trust_function_creators = on|off: 指定是否允许创建可能导致不安全的函数
3、查看二进制日志文件列表及事件
SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name']
show master status;
--修改配置文件
[root@ren7 ~]# vim /etc/my.cnf.d/server.cnf ############################# [server] log_bin = mysql-binlog ##############################
--重启服务 [root@ren7 ~]# systemctl restart mariadb [root@ren7 ~]# mysql -uroot -proot -D ren; --查看二进制日志文件列表
MariaDB [ren]> show master logs; +---------------------+-----------+ | Log_name | File_size | +---------------------+-----------+ | mysql-binlog.000001 | 331 | +---------------------+-----------+ 1 row in set (0.00 sec) MariaDB [ren]> show binary logs; +---------------------+-----------+ | Log_name | File_size | +---------------------+-----------+ | mysql-binlog.000001 | 331 | +---------------------+-----------+ 1 row in set (0.00 sec) --查看当前正在使用的二进制日志文件
MariaDB [ren]> show master status; +---------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +---------------------+----------+--------------+------------------+ | mysql-binlog.000001 | 331 | | | +---------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
--修改数据库的文件 MariaDB [ren]> drop table test4; Query OK, 0 rows affected (0.00 sec) MariaDB [ren]> delete from test where name='李连杰'; Query OK, 1 row affected (0.00 sec) MariaDB [ren]> insert into test set name='漩涡鸣人'; Query OK, 1 row affected (0.01 sec) --再次查看二进制日志文件 MariaDB [ren]> show master status; +---------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +---------------------+----------+--------------+------------------+ | mysql-binlog.000001 | 840 | | | +---------------------+----------+--------------+------------------+ 1 row in set (0.00 sec)
--查看二进制日志文件中的事件(查看binlog内容)
MariaDB [ren]> show binlog events; MariaDB [ren]> show binlog events in 'mysql-binlog.000001'; +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ | Log_name | Pos | Event_type | Server_id | End_log_pos | Info | +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ | mysql-binlog.000001 | 4 | Format_desc | 1 | 256 | Server ver: 10.2.26-MariaDB-log, Binlog ver: 4 | | mysql-binlog.000001 | 256 | Gtid_list | 1 | 285 | [] | | mysql-binlog.000001 | 285 | Binlog_checkpoint | 1 | 331 | mysql-binlog.000001 | | mysql-binlog.000001 | 331 | Gtid | 1 | 373 | GTID 0-1-1 | | mysql-binlog.000001 | 373 | Query | 1 | 483 | use `ren`; DROP TABLE `test4` /* generated by server */ | | mysql-binlog.000001 | 483 | Gtid | 1 | 525 | BEGIN GTID 0-1-2 | | mysql-binlog.000001 | 525 | Query | 1 | 630 | use `ren`; delete from test where name='李连杰' | | mysql-binlog.000001 | 630 | Xid | 1 | 661 | COMMIT /* xid=22 */ | | mysql-binlog.000001 | 661 | Gtid | 1 | 703 | BEGIN GTID 0-1-3 | | mysql-binlog.000001 | 703 | Query | 1 | 809 | use `ren`; insert into test set name='漩涡鸣人' | | mysql-binlog.000001 | 809 | Xid | 1 | 840 | COMMIT /* xid=23 */ | +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ 11 rows in set (0.00 sec) MariaDB [ren]> show binlog events in 'mysql-binlog.000001' from 256; +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ | Log_name | Pos | Event_type | Server_id | End_log_pos | Info | +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ | mysql-binlog.000001 | 256 | Gtid_list | 1 | 285 | [] | | mysql-binlog.000001 | 285 | Binlog_checkpoint | 1 | 331 | mysql-binlog.000001 | | mysql-binlog.000001 | 331 | Gtid | 1 | 373 | GTID 0-1-1 | | mysql-binlog.000001 | 373 | Query | 1 | 483 | use `ren`; DROP TABLE `test4` /* generated by server */ | | mysql-binlog.000001 | 483 | Gtid | 1 | 525 | BEGIN GTID 0-1-2 | | mysql-binlog.000001 | 525 | Query | 1 | 630 | use `ren`; delete from test where name='李连杰' | | mysql-binlog.000001 | 630 | Xid | 1 | 661 | COMMIT /* xid=22 */ | | mysql-binlog.000001 | 661 | Gtid | 1 | 703 | BEGIN GTID 0-1-3 | | mysql-binlog.000001 | 703 | Query | 1 | 809 | use `ren`; insert into test set name='漩涡鸣人' | | mysql-binlog.000001 | 809 | Xid | 1 | 840 | COMMIT /* xid=23 */ | +---------------------+-----+-------------------+-----------+-------------+---------------------------------------------------------+ 10 rows in set (0.00 sec) MariaDB [ren]> show binlog events in 'mysql-binlog.000001' limit 1,2; +---------------------+-----+-------------------+-----------+-------------+---------------------+ | Log_name | Pos | Event_type | Server_id | End_log_pos | Info | +---------------------+-----+-------------------+-----------+-------------+---------------------+ | mysql-binlog.000001 | 256 | Gtid_list | 1 | 285 | [] | | mysql-binlog.000001 | 285 | Binlog_checkpoint | 1 | 331 | mysql-binlog.000001 | +---------------------+-----+-------------------+-----------+-------------+---------------------+ 2 rows in set (0.00 sec)
4、二进制日志滚动
(1)flush logs;
(2)文件超出指定大小;
(3)重启数据库(service mariadb restart / systemctl restart mariadb)
5、查看二进制日志文件(mysqlbinlog命令)
除了前面提到的可以通过show binlog events命令在mysql中查看日志内容,还可以通过mysqlbinlog命令在文件系统下查看对应的二进制日志文件。
[root@ren7 mysql]# pwd /var/lib/mysql [root@ren7 mysql]# mysqlbinlog mysql-binlog.000001 /*!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 #190907 17:15:09 server id 1 end_log_pos 256 CRC32 0x16b33f7c Start: binlog v 4, server v 10.2.26-MariaDB-log created 190907 17:15:09 at startup # Warning: this binlog is either in use or was not closed properly. ROLLBACK/*!*/; BINLOG ' HXVzXQ8BAAAA/AAAAAABAAABAAQAMTAuMi4yNi1NYXJpYURCLWxvZwAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAddXNdEzgNAAgAEgAEBAQEEgAA5AAEGggAAAAICAgCAAAACgoKAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAEEwQADQgICAoKCgF8P7MW '/*!*/; # at 256 #190907 17:15:09 server id 1 end_log_pos 285 CRC32 0x6a3abc7d Gtid list [] # at 285 #190907 17:15:09 server id 1 end_log_pos 331 CRC32 0x01d5789f Binlog checkpoint mysql-binlog.000001 # at 331 #190907 17:27:38 server id 1 end_log_pos 373 CRC32 0x17565195 GTID 0-1-1 ddl /*!100101 SET @@session.skip_parallel_replication=0*//*!*/; /*!100001 SET @@session.gtid_domain_id=0*//*!*/; /*!100001 SET @@session.server_id=1*//*!*/; /*!100001 SET @@session.gtid_seq_no=1*//*!*/; # at 373 #190907 17:27:38 server id 1 end_log_pos 483 CRC32 0xc4f951a5 Query thread_id=9 exec_time=0 error_code=0 use `ren`/*!*/; SET TIMESTAMP=1567848458/*!*/; SET @@session.pseudo_thread_id=9/*!*/; SET @@session.foreign_key_checks=1, @@session.sql_auto_is_null=0, @@session.unique_checks=1, @@session.autocommit=1, @@session.check_constraint_checks=1/*!*/; SET @@session.sql_mode=1411383296/*!*/; SET @@session.auto_increment_increment=1, @@session.auto_increment_offset=1/*!*/; /*!\C utf8 *//*!*/; SET @@session.character_set_client=33,@@session.collation_connection=33,@@session.collation_server=8/*!*/; SET @@session.lc_time_names=0/*!*/; SET @@session.collation_database=DEFAULT/*!*/; DROP TABLE `test4` /* generated by server */ /*!*/; # at 483 #190907 17:28:11 server id 1 end_log_pos 525 CRC32 0x331814aa GTID 0-1-2 trans /*!100001 SET @@session.gtid_seq_no=2*//*!*/; BEGIN /*!*/; # at 525 #190907 17:28:11 server id 1 end_log_pos 630 CRC32 0x2a7828ea Query thread_id=9 exec_time=0 error_code=0 SET TIMESTAMP=1567848491/*!*/; delete from test where name='李连杰' /*!*/; # at 630 #190907 17:28:11 server id 1 end_log_pos 661 CRC32 0x13fd72a8 Xid = 22 COMMIT/*!*/; # at 661 #190907 17:30:06 server id 1 end_log_pos 703 CRC32 0x4fd1715e GTID 0-1-3 trans /*!100001 SET @@session.gtid_seq_no=3*//*!*/; BEGIN /*!*/; # at 703 #190907 17:30:06 server id 1 end_log_pos 809 CRC32 0xd387e70f Query thread_id=9 exec_time=0 error_code=0 SET TIMESTAMP=1567848606/*!*/; insert into test set name='漩涡鸣人' /*!*/; # at 809 #190907 17:30:06 server id 1 end_log_pos 840 CRC32 0x62252207 Xid = 23 COMMIT/*!*/; DELIMITER ; # End of log file ROLLBACK /* added by mysqlbinlog */; /*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/; /*!50530 SET @@SESSION.PSEUDO_SLAVE_MODE=0*/;
二进制日志格式: #190613 14:17:32 server id 1 end_log_pos 666 CRC32 0xeb1cde6b Query thread_id=9 exec_time= 0 error_code=0 use `testdb`/*!*/; 事件发生的日期和时间:190613 14:17:32 事件发生的服务器标识:server id 1 事件的结束位置:end_log_pos 666 事件的类型:Query 事件发生时所在服务器执行此事件的线程ID:thread_id=9 语句的时间戳与将其写入二进制文件中的时间差:exec_time=0 错误代码:error_code=0 事件内容: GTID:Global Transaction ID; 专属属性:GTID
mysqlbinlog:客户端命令工具 mysqlbinlog [options] log_file ... --start-datetime= --stop-datetime= --start-position= --stop-position=
五、中继日志
复制架构中,备服务器用于保存主服务器的二进制日志中读取到的事件;用于实现mysql的主从复制。
1、查看中继日志变量
MariaDB [ren]> show global variables like "%relay%"; +-----------------------+----------------+ | Variable_name | Value | +-----------------------+----------------+ | max_relay_log_size | 1073741824 | | relay_log | | | relay_log_basename | | | relay_log_index | | | relay_log_info_file | relay-log.info | | relay_log_purge | ON | | relay_log_recovery | OFF | | relay_log_space_limit | 0 | | sync_relay_log | 10000 | | sync_relay_log_info | 10000 | +-----------------------+----------------+ 10 rows in set (0.00 sec)
2、变量详解
1 relay_log fileName: 指定中继日志的文件名。【文件名为空,表示禁用了中继日志】 2 relay_log_index: 索引表 3 relay_log_info_file: 记录中继日志文件的相关信息 4 relay_log_purge: 指定是否自动删除无用的中继日志文件 5 relay_log_recovery: 是否可以对中继日志做自动恢复相关的配置 6 relay_log_space_limit: 指定中继日志可以占用的空间大小(0表示不限制)
3、SQL线程应用中继日志流程
六、事务日志
事务日志:transaction log(ib_logfile0,ib_logfile1)
1、查看参数
MariaDB [ren]> show global variables like '%innodb%log%'; +-------------------------------------------+------------+ | Variable_name | Value | +-------------------------------------------+------------+ | innodb_encrypt_log | OFF | | innodb_flush_log_at_timeout | 1 | | innodb_flush_log_at_trx_commit | 1 | | innodb_locks_unsafe_for_binlog | OFF | | innodb_log_arch_dir | | | innodb_log_arch_expire_sec | 0 | | innodb_log_archive | OFF | | innodb_log_block_size | 0 | | innodb_log_buffer_size | 16777216 | | innodb_log_checksum_algorithm | DEPRECATED | | innodb_log_checksums | ON | | innodb_log_compressed_pages | ON | | innodb_log_file_size | 50331648 | | innodb_log_files_in_group | 2 | | innodb_log_group_home_dir | ./ | | innodb_log_optimize_ddl | ON | | innodb_log_write_ahead_size | 8192 | | innodb_max_undo_log_size | 10485760 | | innodb_mirrored_log_groups | 0 | | innodb_online_alter_log_max_size | 134217728 | | innodb_scrub_log | OFF | | innodb_scrub_log_speed | 256 | | innodb_track_redo_log_now | OFF | | innodb_undo_log_truncate | OFF | | innodb_undo_logs | 128 | | innodb_use_global_flush_log_at_trx_commit | OFF | +-------------------------------------------+------------+ 26 rows in set (0.00 sec)
2、部分参数详解
innodb_buffer_pool_size 一般设置成为物理内存的3/4,或者4/5 innodb_log_files_in_group = 2 事务日志文件的个数,默认为2个事务日志文件 innodb_log_file_size = 50331648(48m) 事务日志文件的单个大小48m innodb_log_group_home_dir = ./ 事务日志文件的所在路径,默认就在mariadb的数据目录/var/lib/mysql 事务型存储引擎自行管理和使用(Innodb,myisam引擎是不支持事务,外键,行级锁) redo log : 重做日志 undo log :撤销日志 buffer_pool:缓冲池(一般而言,装完数据库第一个要调的参数)