MySQL 5.7定位消耗CPU高的SQL
MySQL 5.7.23
1.先查看CPU飙高的线程，top -H -p
top - 15:09:26 up 135 days, 7:11, 2 users, LOAD average: 0.12, 0.08, 0.02
Tasks: 34 total, 1 running, 33 sleeping, 0 stopped, 0 zombie
Cpu(s): 12.7%us, 0.0%sy, 0.0%ni, 87.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 32880780k total, 17577884k used, 15302896k free, 601816k buffers
Swap: 4128760k total, 3916k used, 4124844k free, 7478260k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
23974 mysql 20 0 1658m 358m 12m R 99.9 1.1 0:05.52 mysqld
12295 mysql 20 0 1658m 358m 12m S 0.3 1.1 0:02.44 mysqld
12283 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:01.60 mysqld
12284 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:00.00 mysqld
12285 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:02.63 mysqld
12286 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:02.24 mysqld
12287 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:01.68 mysqld
12288 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:01.77 mysqld
12289 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:01.64 mysqld
12290 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:01.80 mysqld
12291 mysql 20 0 1658m 358m 12m S 0.0 1.1 0:02.37 mysqld
2.使用MySQL内部的表定位问题SQL。
SELECT a.THREAD_OS_ID,b.user,b.host,b.db,b.command,b.time,b.state,b.info
FROM performance_schema.threads a,information_schema.processlist b
WHERE b.id = a.processlist_id;
THREAD_OS_ID USER HOST db command TIME state info
20891 root 10.10.18.153:1499 jira SLEEP 345 (NULL)
20892 root 10.10.18.153:1500 jira SLEEP 345 (NULL)
23651 root 10.10.18.201:19387 (NULL) SLEEP 2198 (NULL)
23650 root 10.10.18.201:21445 (NULL) QUERY 0 executing SELECT a.THREAD_OS_ID,b.user,b.host,b.db,b.command,b.time,b.state,b.info
FROM performance_schema.threads a,information_schema.processlist b
WHERE b.id = a.processlist_id LIMIT 0, 1000
23970 root 10.10.18.201:21446 (NULL) SLEEP 199 (NULL)
23974 root 10.10.18.201:21466 sys QUERY 29 Sending DATA SELECT a.* FROM test a,test b,test c ,test d
ORDER BY a.value
LIMIT 0, 1000