Jon Nelson <jnelson+pgsql@xxxxxxxxxxx> writes: > Your comment regarding "each individual de-duplication looked like it > would fit in work_mem" doesn't really make sense, exactly. Maybe I'm > misunderstanding you. Yeah. What I was suggesting was to NOT add the DISTINCT's, but instead raise work_mem high enough so you get just one HashAggregation step at the top level. (Although I think this only works in 8.4 and up.) That should be faster than two levels of de-duplication. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
