Difference Between Tomcat Logs and Performance Logs in Appian ?

Tomcat logs are for troubleshooting application server errors. Performance logs are for monitoring performance, measuring execution times, and finding bottlenecks.

Tomcat logs

The main file is tomcat-stdOut.log. It helps you investigate:

1. Application server errors and their messages
2. Java exceptions and stack traces
3. Plug-in problems during deployment, initialization, or execution
4. Startup errors, which depending on configuration may appear in Tomcat output or in separate application server logs

For example, suppose a process model uses a custom plug-in smart service and the node takes unusually long to finish. Appian may log a work-poller error saying it couldn’t get the execution threads it needed. tomcat-stdOut.log is where you’d confirm that.

Appian also writes tomcat-access.log, which records HTTP requests, response status codes, and request processing times.

Performance logs

These are in <APPIAN_HOME>/logs/perflogs/ and show which operations are slow and how Appian resources are being used.

If users report that an interface takes several seconds to load, check these files:

1. sail_details.csv for slow interface evaluations
2. data_store_details.csv for slow data store operations
3. expressions_details.csv for expensive expression evaluations

Together they show whether the delay comes from interface evaluation, database access, or expression execution.

Performance logs have three levels of detail:

1. Summary: aggregated metrics, typically recorded every five minutes
2. Details: more granular metrics, typically written hourly
3. Trace: event-level diagnostics, disabled by default for many log types

Tomcat logs are only one category of Appian system logs, so not every Appian error ends up in tomcat-stdOut.log.

Official reference: Appian Documentation — System Logs