KB-1943 The application server fails to start with a "Too many connections" error thrown in the application server log

Symptoms

The application server fails to start with the following error observed in the application server log:

ERROR [org.jboss.jca.core.tx.jbossts.XAResourceRecoveryImpl] (Periodic Recovery) IJ000906: Error during crash recovery: jdbc/AppianPrimaryDS (Could not create connection): javax.resource.ResourceException: Could not create connection
	at org.jboss.jca.adapters.jdbc.xa.XAManagedConnectionFactory.getXAManagedConnection(XAManagedConnectionFactory.java:522)
...
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection,  message from server: "Too many connections"

Cause

The application server will throw this error when attempting to connect to the database server, and all available connections are in use by other clients. More information regarding this database error can be found in the MySQL documentation.

Action

Set the max_connections variable to a larger value. For MySQL, this can be done without having to restart the database. Refer to the respective database documentation for the exact steps on how to perform this action on the database server.
Restart the database server which will reset the connections if you wish to not increase the max_connections variable.

Affected Versions

This article applies to all versions of Appian.

Last Reviewed: May 2019