With Connector/J load balancing, we're often seeing: Com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications Link Failure

(Doc ID 1526709.1)

Last updated on FEBRUARY 16, 2017

Applies to:

MySQL Connectors - Version 5.2 and later
Information in this document applies to any platform.


We are using the Connector/J load balancing with a URL similar to this:


We have keep alive functionality enabled in our connection pool and we also enabled the functionality to check connection validity at checkout in our connection pool. That's why it's not expected. The X in the error above is also less than wait_timeout.

We need to find out why this is still happening.


Sign In with your My Oracle Support account

Don't have a My Oracle Support account? Click to get started

My Oracle Support provides customers with access to over a
Million Knowledge Articles and hundreds of Community platforms