Server with jBPM 6 application takes long time to start

Issue

Startup time of a Tomcat instance with jBPM application has increased significantly recently. Generally it happens when many pending timers exist for jBPM processes.

Inspecting the log during the startup, we see a lot of request statements for the SessionInfo table:

select sessioninf0_.id as id3290_0_, sessioninf0_.lastModificationDate as lastModificationDate3290_0_, sessioninf0_.rulesByteArray as rulesByteArray3290_0_, sessioninf0_.startDate as startDate3290_0_, sessioninf0_.OPTLOCK as OPTLOCK3290_0_ from SessionInfo sessioninf0_ where sessioninf0_.id=7812

In addition, we found out that this is happening only when we use runtime manager type as PER_PROCESS_INSTANCE. If we use SINGLETON then this behavior is not observed.