On Tue, Jun 7, 2016 at 12:28 AM, Alvaro Herrera <alvhe...@2ndquadrant.com> wrote: > Tom Lane wrote: >> Alvaro Herrera <alvhe...@2ndquadrant.com> writes: > >> > I can't imagine that the server is avoiding hash aggregation on a 1MB >> > work_mem limit for data that's a few dozen of bytes. Is it really doing >> > that? >> >> Yup: > > Aha. Thanks for testing. > >> Now that you mention it, this does seem a bit odd, although I remember >> that there's a pretty substantial fudge factor in there when we have >> no statistics (which we don't in this example). If I ANALYZE ctv_data >> then it sticks to the hashagg plan all the way down to 64kB work_mem. > > Hmm, so we could solve the complaint by adding an ANALYZE. I'm open to > that; other opinions?
We could just enforce work_mem to 64kB and then reset it. -- Michael -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers