On Fri, 21 May 2021 at 03:52, Laurenz Albe <laurenz.a...@cybertec.at> wrote: > Just sending a reply to -hackers so I can add it to the commitfest.
I had a look at the patch in [1] and I find it a bit weird that we'd write the following about autovacuum_work_mem in our docs: + <para> + Note that <command>VACUUM</command> has a hard-coded limit of 1GB + for the amount of memory used, so setting + <varname>autovacuum_work_mem</varname> higher than that has no effect. + </para> Since that setting is *only* used for auto vacuum, why don't we just limit the range of the GUC to 1GB? Of course, it wouldn't be wise to backpatch the reduced limit of autovacuum_work_mem as it might upset people who have higher values in their postgresql.conf when their database fails to restart after an upgrade. I think what might be best is just to reduce the limit in master and apply the doc patch for just maintenance_work_mem in all supported versions. We could just ignore doing anything with autovacuum_work_mem in the back branches and put it down to a historical mistake that can't easily be fixed now. I've attached what I came up with. What do you think? [1] https://www.postgresql.org/message-id/514fe5ce4714b7b33cb0a611f0c7b72df413bef5.camel%40cybertec.at
limit_vacuum_memory_to_1gb.patch
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