pgq.maint_retry_events(): lock table to allow only single mover
pgq.maint_retry_events(): lock table to allow only single mover

Use SHARE UPDATE EXCLUSIVE lock, which will not conflict with inserts.

tarvip/skytools,tarvip/skytools,overdrive3000/skytools,overdrive3000/skytools,markokr/skytools,overdrive3000/skytools,tarvip/skytools,markokr/skytools,markokr/skytools