* Tom Lane (t...@sss.pgh.pa.us) wrote: > "Joshua D. Drake" <j...@commandprompt.com> writes: > > At PGConf US Philly last week I was talking with Jim and Jan about > > performance. One of the items that came up is that PostgreSQL can't run > > full throttle for long periods of time. The long and short is that no > > matter what, autovacuum can't keep up. This is what I have done: > > Try reducing autovacuum_vacuum_cost_delay more, and/or increasing > autovacuum_vacuum_cost_limit.
Or get rid of the cost delay entirely and let autovacuum actually go as fast as it can when it's run. The assertion that it can't keep up is still plausible, but configuring autovacuum to sleep regularly and then complaining that it's not able to keep up doesn't make sense. Reducing the nap time might also be helpful if autovacuum is going as fast as it can and it's able to clear a table in less than a minute. There have been discussions on this list about parallel vacuum of a particular table as well; to address this issue I'd encourage reviewing those discussions and looking at writing a patch to implement that feature as that would address the case where the table is large enough that autovacuum simply can't get through all of it before the other backends have used all space available and then substantially increased the size of the relation (leading to vacuum on the table running for longer). Thanks! Stephen
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