On Wed, Jul 7, 2021 at 8:44 PM David Rowley <dgrowle...@gmail.com> wrote: > > On Sun, 4 Jul 2021 at 22:38, David Rowley <dgrowle...@gmail.com> wrote: > > I could do with a 2nd opinion about if we should just adjust the > > maximum value for the autovacuum_work_mem GUC to 1GB in master. > > > > I'm also not sure if since we'd not backpatch the GUC max value > > adjustment if we need to document the upper limit in the manual. > > I was just looking at this again and I see that GIN indexes are able > to use more than 1GB of memory during VACUUM.
I think you meant that autovacuums can use more than 1GB of memory during cleaning up a gin pending list (in ginInsertCleanup()). The description updated by that commit is not true as of now as you pointed out but IIUC it uses maintenance_work_mem *in addition to* the same amount memory used by lazy vacuum. This memory usage seems rather weird to me. Is it worh considering having gin pending list cleanup use work_mem instead of maintenance_work_mem also in autovacuum cases like btree indexes do? If we do that, the description will become true, although we might need to update work_mem section somewhat. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
