Why does Quartz Scheduler(JobSToreCMT) require the use of two datasources?

Question

I found this annswer: 1. Long answer to Quartz requiring to data sources, however, if you want an even deeper answer, I believe I’ll need to dig into the source code or do more research: a. JobStoreCMT relies upon transactions being managed by the application which is using Quartz. A JTA transaction must be in progress before attempt to schedule (or unschedule) jobs/triggers. This allows the "work" of scheduling to be part of the applications "larger" transaction. JobStoreCMT actually requires the use of two datasources - one that has it's connection's transactions managed by the application server (via JTA) and one datasource that has connections that do not participate in global (JTA) transactions. JobStoreCMT is appropriate when applications are using JTA transactions (such as via EJB Session Beans) to perform their work. (Ref; http://quartz-scheduler.org/documentation/quartz-1.x/configuration/ConfigJobStoreCMT)

However, there is a believed conflict with a non transactional driver in our particular application. Does anyone know if Quartz (JobsStoreCMT) can just work with just a transactional data source?

Answer 1

Does anyone know if Quartz (JobsStoreCMT) can just work with just a transactional data source?

No you must have a datasource of each type. Invocations on the API by the client application use the connections that are XA-capable, so that the work join's the application's transaction. Work done by the scheduler's internal threads use the non-XA connections.