mysql---慢查询

最新推荐文章于 2024-07-08 00:42:02 发布

xing2233

最新推荐文章于 2024-07-08 00:42:02 发布

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默认慢查询是没有开启的
mysql> show variables like '%slow%';
+---------------------+---------------------------------+
| Variable_name       | Value                           |
+---------------------+---------------------------------+
| log_slow_queries    | OFF                             |
| slow_launch_time    | 2                               |
| slow_query_log      | OFF                             |
| slow_query_log_file | /var/run/mysqld/mysqld-slow.log |
+---------------------+---------------------------------+

永久开启慢查询
vi /etc/my.cnf
在[mysqld]下添加
long_query_time=1	#设置超过多少秒的查询算慢查询
log-slow-queries=/var/run/mysqld/mysqld-slow.log	#设置慢查询日志，这个是默认路径

然后/etc/init.d/mysqld restart

慢查询日志默认查看工具mysqldumpslow
[root@localhost ~]# 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 (al, at, ar, c, l, r, t), 'at' is default
                al: average lock time
                ar: average rows sent
                at: average query time
                 c: count
                 l: lock time
                 r: rows sent
                 t: query time
  -r           reverse the sort order (largest last instead of first)
  -t NUM       just show the top n queries
  -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
  -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