KB-2084 Engines fail to start following hotfix deployment or upgrade to Appian versions 19.2 / 19.3 / 19.4

Symptoms

In an Self-manageds environment, Appian engines fail to start following a hotfix deployment or version upgrade due to transaction replay error with the following message in the service_manager.log:

ERROR com.appian.komodo.translog.OutstandingRequestsTracker - Outstanding write requests was decremented again after the all writes logged event.

Cause

This issue has been hotfixed via AN-150186 in Appian versions 19.2 and later.

Action

Apply the latest hotfix to your Appian installation or upgrade to the latest version of Appian.

Workaround

Open a support case with Appian Technical Support to receive the fix for this issue and follow the instructions below to apply the fix:

1. Download and unzip the komodo-1.236.0.zip file provided by Appian Support to any directory that is not <APPIAN_HOME>.
2. Shutdown all components of Appian gracefully.
3. Rename <APPIAN_HOME>/services/bin to <APPIAN_HOME>/services/bin_backup.
4. Rename <APPIAN_HOME>/services/lib to <APPIAN_HOME>/services/lib_backup.
5. From the unzipped komodo-1.236.0.zip file, copy the ‘bin’ directory into <APPIAN_HOME>/services.
6. From the unzipped komodo-1.236.0.zip file, copy the ‘lib’ directory into <APPIAN_HOME>/services.
7. Start the engines and associated services (Service Manager, Kafka, Zookeeper) on all engine nodes using the start script.
8. Stop the engines and associated services on all engine nodes using the stop script. 
9. Start Appian normally using the steps provided in our Starting and Stopping Appian documentation.

After completing Appian startup, follow the procedures below:

1. Remove <APPIAN_HOME>/services/bin_backup.
2. Remove <APPIAN_HOME>/services/lib_backup.
   

Affected Versions

This article applies to Appian 19.2, 19.3, and 19.4.

Last Reviewed: June 2020