On 11 October 2010 18:37, Tom Lane <t...@sss.pgh.pa.us> wrote: > Dean Rasheed <dean.a.rash...@gmail.com> writes: >> The estimate of 200 x 8K is below work_mem, so it uses a hash >> aggregate. In reality, each tuplesort allocates around 30K initially, >> so it very quickly uses over 1GB. A better estimate for the aggregate >> wouldn't improve this situation much. > > Sure it would: an estimate of 30K would keep the planner from using > hash aggregation. >
Not if work_mem was 10MB. Regards, Dean -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
