Requests stuck in Pending Standby

[VinodN]

Hi Erman,

Faced a weird problem yesterday. In a test instance a user's requests were going into Pending Standby. Also, at the same time the requests were seen in Standard Manager, Custom Mgr (which we had created) and CRM queue in the Administer form.

I found this note - Concurrent Requests Stuck In Pending Status In Conflict Resolution Manager (Doc ID 2604091.1) and executed the query from it:

select * from fnd_concurrent_requests where concurrent_program_id in
(SELECT p.concurrent_program_id FROM FND_CONCURRENT_PROGRAM_SERIAL s, fnd_concurrent_programs_tl p WHERE
(s.to_run_application_id in (select application_id from fnd_concurrent_programs_tl where user_concurrent_program_name='Program Name'))
and
(s.to_run_concurrent_program_id in (select concurrent_program_id from fnd_concurrent_programs_tl where user_concurrent_program_name='Program Name'))
and s.running_concurrent_program_id=p.concurrent_program_id)
and phase_code <> 'C';

The query returned 3 rows. One of them was our user's request and other two were requets from Nov 2023. I updated their status to completed and immediately the user's request ran and completed.
Could you please help me understand what happened here?

[ErmanArslansOracleBlog]

You can define that a concurrent program is incompatible with other concurrent programs. Say that
you define an incompatible rule for concurrent program A with program B. As a results, program A will not
run in parallel with program B. Whenever the request is being submitted, it will check for any incompatible
rules, and if it finds any incompatibilities, then that request will go in the pending phase and wait for other
dependent requests to complete. It will continue to run only after the completion of the currently running
dependent incompatible concurrent request. These concurrent manager dependencies are managed by the
conflict resolution manager

In your case, you should check 2 things; incompatible rules and the specialization rules.

[VinodN]

Thanks Erman!