Zend Framework多个数据库停止使用慢查询

Question

I'm running a big Zend Framework web application with 5 database, independent of each other, distributed on 2 database servers running on Mysql 5.6.36 - CentOS7 with 16gb ram 8 core processor each. However, if one of the 2 database servers stops responding because of slows query, the users on the other server cannot access the web application. The only way to turn on the application is to restart mysql on that server. I try different things without success. The strange thing is that if I turn off one of the servers the system continues to work correctly.

Answer 1

It's hard to offer a meaningful answer, because you've given us no information about your tables or your queries (in fact, you haven't asked a question at all, you've just told us a story! :-).

I will offer a guess that you are using MyISAM for one or more of your tables. This means a query from one client locks the table(s) it queries, and blocks concurrent updates from other clients.

To confirm you have this problem, use SHOW PROCESSLIST on each of your two database servers at the time you experience the contention between web apps. You might see a bunch of queries stuck waiting for a lock (it may appear in the processlist with the state of "Updating").

If so, you might have better luck if you alter your tables' storage engine to InnoDB. See https://dev.mysql.com/doc/refman/5.7/en/converting-tables-to-innodb.html