MySQL查找占用CPU、MEMORY比较高的SQL
通过top -p mysqlpid -H 可以找到thread_os_id ->
通过thread_os_id 和 performance_schema.threads 找到thread_id ->
通过thread_id和performance_schema.events_statements_current 找到sql语句
[root@node2 ~]# ps -ef | grep -i mysql
mysql 2296 1211 18 14:17 ? 00:03:46 /home/db/mysql/product/bin/mysqld --basedir=/home/db/mysql/product --datadir=/mysqldata/data --plugin-dir=/home/db/mysql/product/lib/plugin --user=mysql --log-error=/mysqldata/logs/mysql_error.log --pid-file=/mysqldata/data/mysqld.pid --socket=/home/db/mysql/product/mysql.sock --port=13306
[root@node2 ~]# top -p 2296 -H
top - 14:59:55 up 42 min, 4 users, load average: 0.41, 0.81, 1.39
Threads: 67 total, 2 running, 65 sleeping, 0 stopped, 0 zombie
%Cpu(s): 94.7 us, 4.7 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.7 si, 0.0 st
KiB Mem : 2238208 total, 77696 free, 943520 used, 1216992 buff/cache
KiB Swap: 2621436 total, 2621436 free, 0 used. 1139404 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAN
2966 mysql 20 0 6212608 868916 30128 R 97.3 38.8 11:46.51 mysqld
2460 mysql 20 0 6212608 868916 30128 R 0.3 38.8 0:09.28 mysqld
2296 mysql 20 0 6212608 868916 30128 S 0.0 38.8 0:00.79 mysqld 系统PID=2966 占用CPU 97%
通过performance_schema.threads.thread_os_id=2966可以找到thread_id,processlist_id ;
root@localhost 15:03:34 [performance_schema]>select thread_id,name ,PROCESSLIST_ID,THREAD_OS_ID from threads where thread_os_id = 2966 ;
+-----------+---------------------------+----------------+--------------+
| thread_id | name | PROCESSLIST_ID | THREAD_OS_ID |
+-----------+---------------------------+----------------+--------------+
| 78 | thread/sql/one_connection | 10 | 2966 |
+-----------+---------------------------+----------------+--------------+ 通过performance_schema.events_statements_current.thread_id = 78 可以找到当前占用cpu的SQL：
root@localhost 15:07:37 [performance_schema]>select DIGEST_TEXT from performance_schema.events_statements_current where thread_id = 78 ;
+---------------------------------------------------------------------+
| DIGEST_TEXT |
+---------------------------------------------------------------------+
| SELECT * FROM `t` AS `t1` , `t` AS `t2` , `t` AS `t3` , `t` AS `t4` |
+---------------------------------------------------------------------+DIGEST_TEXT 的长度由变量max_digest_length控制:
root@localhost 16:08:01 [performance_schema]>show variables like 'max_digest_length' ;
+-------------------+-------+
| Variable_name | Value |
+-------------------+-------+
| max_digest_length | 1024 |
+-------------------+-------+