KB-2184 "java.sql.SQLException: Unable to obtain a connection within configured timeout" observed in application server log

Symptoms

The following exception appears in the tomcat-stdOut.log file:

Caused by: java.sql.SQLException: Unable to obtain a connection within configured timeout

In cases where this exception is encountered regularly, application features that interact with databases may experience degraded performance. This can manifest in a number of ways, ranging from user-facing application slowness to frequently failing process model execution.

Cause

The application server was unable to establish a connection to the business database within the default 10 second timeout. The timeout is in place to prevent the application from locking up if a large number of threads are blocked waiting for a database connection to initialize. In many cases, this error message is a symptom of an unreliable network configuration between the web server and the database, rather than an issue localized to either of those components.

Action

Work with your database administrators, network operations team, and/or Appian Support to verify the reliability of the network connection between the application server and the database instance.

Workaround

In cases when the network conditions or database responsiveness cannot be improved, increase or disable the connection timeout properties. 

DISCLAIMER: These properties only affect the way the application server reacts to slow connection attempts. Without addressing the underlying issues, modifications to these values may degrade application performance.

Self-Managed

1. Modify or add the following properties to the custom.properties file:
   • conf.data.datasources.internal.CONNECTION_TIMEOUT_MS=<time in milliseconds>
   • conf.data.datasources.internal.connectionTimeout.enabled=false
2. Restart the application server.

Notes: