我们有时候需要查看mysql的执行历史，比如我们做sql优化的时候，起码要知道执行的sql是什么，框架一般会帮我们拼装sql，所以在程序中不一定能够打印出sql，这个时候就需要mysql的general
log了。

查看设置mysql genneral log

show VARIABLES like '%general_log%';

set GLOBAL general_log = off;// on-打开; off-关闭

general_log ON
general_log_file    /var/log/mysql/query.log

使用mysql general log

tail -f /path/to/log/query.log | grep yourtable 13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2) 13518 Query DESCRIBE `babysitter_tips` 13518 Close stmt 13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5 13518 Reset stmt 13518 Close stmt 13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '1') AND (is_enable = 1) AND (is_tip = 2) AND (tip_id > 15440) 13518 Close stmt 13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2) 13518 Query DESCRIBE `babysitter_tips` 13518 Close stmt 13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5 13518 Reset stmt 13518 Close stmt 13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '3') AND (is_enable = 1) AND (is_tip = 2) AND (tip_id > '') 13518 Close stmt 13518 Prepare SELECT count(*) AS `count` FROM `babysitter_tips` WHERE (tip_type = '2') AND (is_enable = 1) AND (is_tip = 2) 13518 Query DESCRIBE `babysitter_tips` 13518 Close stmt 13518 Prepare SELECT `babysitter_tips`.* FROM `babysitter_tips` WHERE (tip_type = '2') AND (is_enable = 1) AND (is_tip = 2) ORDER BY `created_time` desc LIMIT 5 13518 Reset stmt 13518 Close stmt

清理mysql general log

general log会比较大，所以默认市关闭的，所以最好需要的时候打开，随手关闭。如果发现query.log过大，可以手动删除。在general log打开的情况下，query.log文件类似于mysql表的lock情况，不允许修改和删除，关闭general log就可以操作了。