MySQL中的通用查询日志(General Query Log)

MySQL中的通用查询日志(General Query Log)

1. 以什么形式来记录？
log_output系统变量来决定的，可选值 TABLE, FILE, 或者 NONE，默认值是FILE，可以同时选择TABLE和FILE，中间用逗号隔开。

2. 如何开启？
设置general_log系统变量，设置为ON,OFF

3. 具体写到哪里？
如果是写到文件里，由general_log_file指定，如果要看默认值，可以使用show variables like 'general_log_file'。如果写到表里，则写到mysql.general_log

4. 何时开启？
可以在启动MySQL server的时候开启，指定--log_output，--general_log和--general_log_file选项；也可以在运行时开启，设置环境变量log_output，general_log和general_log_file

5. 记录什么内容？

The server writes information to this log when clients connect or disconnect, and it logs each SQL statement received from clients.

测试：
下面的测试中分别从db2b和db2a上连接了MySQL数据库，并进行了一些增、删、改、查的动作，看一下通用查询日志记录了哪些内容：
db2a为MySQL server:

mysql> set global general_log=1;
mysql> show variables like 'general_log_file';
+------------------+-------------------------+
| Variable_name | Value |
+------------------+-------------------------+
| general_log_file | /var/lib/mysql/db2a.log |
+------------------+-------------------------+
1 row in set (0.04 sec)

mysql> alter user 'user1'@'db2b' identified by 'user1';

db2b上：
root@db2b:~# mysql -h db2a -u user1 -pwrong sample
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'user1'@'db2b' (using password: YES)
root@db2b:~# mysql -h db2a -u user1 -puser1 sample
mysql> drop table test1;
mysql> create table test1(year);
mysql> create table test1(year int);
mysql> insert into test1 values(2007),(2010);
mysql> select * from test1 where year > 2008;
mysql> delete from test1 where year < 2008;
mysql> show variables like 'default_password_lifetime';
mysql> quit

db2a上：
root@db2a:~# mysql -u root -pqingsong sample;
mysql> select * from test2;
mysql> set global general_log=0;

看一下 cat /var/lib/mysql/db2a.log

root@db2a:~#  cat /var/lib/mysql/db2a.log 
mysqld, Version: 5.7.18-log (MySQL Community Server (GPL)). started with:
Tcp port: 3306  Unix socket: /var/run/mysqld/mysqld.sock
Time                               Id Command    Argument
2017-09-18T12:26:25.428531Z        16 Query     show variables like 'general_log_file'
2017-09-18T12:26:32.415259Z        16 Query     ALTER USER 'user1'@'db2b' IDENTIFIED WITH 'mysql_native_password' AS ''
2017-09-18T12:26:41.703283Z        23 Connect   user1@db2b on sample using SSL/TLS
2017-09-18T12:26:41.703388Z        23 Connect   Access denied for user 'user1'@'db2b' (using password: YES)
2017-09-18T12:26:50.012271Z        24 Connect   user1@db2b on sample using SSL/TLS
2017-09-18T12:26:50.049494Z        24 Query     show databases
2017-09-18T12:26:50.055891Z        24 Query     show tables
2017-09-18T12:26:50.068155Z        24 Field List        A 
2017-09-18T12:26:50.084237Z        24 Field List        B 
2017-09-18T12:26:50.084982Z        24 Field List        child 
2017-09-18T12:26:50.085600Z        24 Field List        employee 
2017-09-18T12:26:50.086364Z        24 Field List        s2 
2017-09-18T12:26:50.087536Z        24 Field List        t1 
2017-09-18T12:26:50.088150Z        24 Field List        t2 
2017-09-18T12:26:50.088679Z        24 Field List        test1 
2017-09-18T12:26:50.089221Z        24 Field List        test2 
2017-09-18T12:26:50.091282Z        24 Query     select @@version_comment limit 1
2017-09-18T12:26:56.784946Z        24 Query     drop table test1
2017-09-18T12:27:08.058195Z        24 Query     create table test1(year int)
2017-09-18T12:27:12.764736Z        24 Query     insert into test1 values(2007),(2010)
2017-09-18T12:27:16.740802Z        24 Query     select * from test1 where year > 2008
2017-09-18T12:27:22.588631Z        24 Query     delete from test1 where year < 2008
2017-09-18T12:27:26.476919Z        24 Query     show variables like 'default_password_lifetime'
2017-09-18T12:27:29.008515Z        24 Quit
2017-09-18T12:28:09.577592Z        25 Connect   root@localhost on sample using Socket
2017-09-18T12:28:09.638443Z        25 Query     show databases
2017-09-18T12:28:09.660399Z        25 Query     show tables
2017-09-18T12:28:09.661135Z        25 Field List        A 
2017-09-18T12:28:09.661638Z        25 Field List        B 
2017-09-18T12:28:09.662730Z        25 Field List        child 
2017-09-18T12:28:09.663875Z        25 Field List        employee 
2017-09-18T12:28:09.665264Z        25 Field List        s2 
2017-09-18T12:28:09.666117Z        25 Field List        t1 
2017-09-18T12:28:09.666671Z        25 Field List        t2 
2017-09-18T12:28:09.667845Z        25 Field List        test1 
2017-09-18T12:28:09.668325Z        25 Field List        test2 
2017-09-18T12:28:09.668993Z        25 Query     select @@version_comment limit 1
2017-09-18T12:28:23.349771Z        25 Query     select * from test2
2017-09-18T12:28:27.891398Z        25 Query     set global general_log=0

可以看到，执行的drop/create table， select/insert/update/delete，show variables，set，以及连接动作(成功与否)/退出都被记录了下来。

参考链接：
https://dev.mysql.com/doc/refman/5.7/en/log-destinations.html
https://dev.mysql.com/doc/refman/5.7/en/query-log.html