Running Mysqlcheck After 5.6.35 Update Causes Connections Errors (Doc ID 2240421.1)

Last updated on MAY 14, 2017

Applies to:

MySQL Server - Version 5.6 and later
Information in this document applies to any platform.
mysqlcheck tool is used for both MyISAM and InnoDB engines. The MEMORY engine doesn't support the mysqlcheck

For a mix of engines on a single MySQL instance, mysqlcheck may lock tables for an extensive period of time, depending on the tables size. Mysqlcheck can also prevent some InnoDB engine operations. On InnoDB tables it is recommended to add the quick option for a faster health check. For example for all tables on the server:
shell# mysqlcheck -Acq --auto-repair

Mysqlcheck is also invoked by the mysql_upgrade.

For certain scenarios, the mysqlcheck may lock tables and the MySQL Connector or Application due to timeout limitations may create new sessions until the max_connections is reached. New connections will be refused, "Server unresponsive". We recommend adding the quick option and / or increase the number of max_connections during the mysqlcheck running schedule.

Goal

The mysqlcheck makes the MySQL Sever unresponsive: mysqlcheck -Ac --auto-repair

Solution

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