Itagaki Takahiro <itagaki.takah...@gmail.com> writes: > On Wed, Nov 17, 2010 at 01:12, Alvaro Herrera <alvhe...@alvh.no-ip.org> wrote: >> So for the initial implementation, we could just have each worker set >> its local maintenance_work_mem to autovacuum_maintenance_memory / >> max_workers. >> That way there's never excessive memory usage.
> It sounds reasonable, but is there the same issue for normal connections? > We can limit max connections per user, but there are no quota for total > memory consumed by the user. It might not be an autovacuum-specifix issue. I agree with Itagaki-san: this isn't really autovacuum's fault. Another objection to the above approach is that anytime you have fewer than max_workers AV workers, you're not using the memory well. And not using the memory well has a *direct* cost in terms of increased effort, ie, extra indexscans. So this isn't something to mess with lightly. I can see the possible value of decoupling autovacuum's setting from foreground operations, though. What about creating autovacuum_maintenance_mem but defining it as being the maintenance_work_mem setting that each AV worker can use? If people can't figure out that the total possible hit is maintenance_work_mem times max_workers, their license to use a text editor should be revoked. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers