If a regular backend worker becomes blocked waiting for a lock held by an autovacuum worker, then , depending on some decision made by deadlock detector, the autovacuum worker may be signalled to terminate
This results in messages such as these in the statement log
ERROR: canceling autovacuum task CONTEXT: automatic vacuum of table "somedb.aschema.thistable"
Is there any configuration parameter which controls this? including deferring or even completely eliminating this cancelling? so that, in the eliminate case, the waiter would simply go on waiting until the autovacuum eventually finishes "thistable"?
I have not seen any parameter to do this. Note that I don't mean some parameter which affects all locking behaviour, only this autovacuum case.
Why would you want this?
If the autovacuum is cancelled, it will re-execute again in the near future, once your interrupting SQL has released locks.
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Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
