che_type' OR Variable_name = 'query_cache_size' OR Variable_name = 'init_connect'
2017-07-20T21:45:02.738868Z28556029 Query SHOW COLLATION
2017-07-20T21:45:02.739941Z28556029 Query SET character_set_results = NULL
2017-07-20T21:45:02.740275Z28556029 Query SET autocommit=1
那问题基本确定了,客户端请求都没到我们这边就抛出了上述的异常,和平台方再三沟通确认下,最后平台方查证是因为在执行插入前他们需要先从 SQL task 表取出 SQL 和更新 task 状态,结果这张表由于在整点存在大量 insert 和 update 并发,导致部分 SQL 等待 lock 超时了。。。
3、MySQL 日志分析脚本
由于凌晨是数据仓库的业务高峰,很多问题都是在这个时候爆发,一些诡异的问题往往是过了这个村就没这个店了,白天无法复现。如何能捕获我们关心的日志,便于快速的定位问题,这个是重中之重,这里我写了个小脚本,crontab 部署,可以选择时间范围开启,每分钟采样一次日志,需要说明的是 general log 没事别轻易开启,否则对数据库性能损耗较大。
# crontab 部署方式:
# */1 0-10 * * * cd /opt/ooxx/script && bash mysql_perf.sh >> logs/mysql_perf.log.`date -I` 2>&1
date -Iseconds
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> top -bn1|head'
top -bn1|head
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SHOW ENGINE INNODB STATUS\G '
mysql -uroot -pooxx -h127.0.0.1 -e 'SHOW ENGINE INNODB STATUS\G'
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> show open tables where in_use>0;'
mysql -uroot -pooxx -h127.0.0.1 -e 'show open tables where in_use>0;'
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> show full processlist;'
mysql -uroot -pooxx -h127.0.0.1 -e 'show full processlist;'
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SELECT * FROM `information_schema`.`innodb_trx` ORDER BY `trx_started`; '
mysql -uroot -pooxx -h127.0.0.1 -e 'SELECT * FROM `information_schema`.`innodb_trx` ORDER BY `trx_started`;'
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> SELECT * FROM `information_schema`.`innodb_locks`;'
mysql -uroot -pooxx -h127.0.0.1 -e 'SELECT * FROM `information_schema`.`innodb_locks`;'
echo
echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>> show status like '%lock%';"
mysql -uroot -pooxx -h127.0.0.1 -e "show status like '%lock%';"
echo
echo '>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> show global status like "table_locks%";'
mysql -uroot -pooxx -h127.0.0.1 -e 'show global status like "table_locks%";'
echo
echo ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>> too long omit..."
mysql -uroot -pooxx -h127.0.0.1 -e "select r.trx_isolation_level, r.trx_id waiting_trx_id, r.trx_mysql_thread_id waiting_trx_thread, r.trx_state waiting_trx_state, lr.lock_mode waiting_trx_lock_mode, lr.lock_type waiting_trx_lock_type, lr.lock_table waiting_trx_l