On 11/29/14, 2:22 AM, Andres Freund wrote:
Hi,I've more than once seen that autovacuums on certain tables never succeed because regular exclusive (or similar) lockers cause it to give way/up before finishing. Usually if some part of the application uses explicit exclusive locks. In general I think it's quite imortant that autovacuum bheaves that way. But I think it might be worhtwile to offer an option to disable that behaviour. If some piece of application logic requires exclusive locks and that leads to complete starvation of autovacuum, there's really nothing that can be done but to manually schedule vacuums right now. I can see two possible solutions: 1) Add a reloption that allows to configure whether autovacuum gives way to locks acquired by user backends. 2) Add a second set of autovacuum_*_scale_factor variables that governs a threshhold after which autovacuum doesn't get cancelled anymore. Opinions?
What do you mean by "never succeed"? Is it skipping a large number of pages? Might re-trying the locks within the same vacuum help, or are the user locks too persistent? -- Jim Nasby, Data Architect, Blue Treble Consulting Data in Trouble? Get it in Treble! http://BlueTreble.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
