On Tue, Dec 23, 2008 at 11:14 AM, George Pavlov <gpavlov@xxxxxxxxxxxxxx> wrote: > You don't say what PG version you are on, but just for kicks you may try > using GROUP BY instead of DISTINCT. Yes, the two should perform the > same, but with 8.1 (or maybe 8.0) I had seen situations where GROUP BY > was faster (admittedly this happened with more complex queries). So, try > this: Even in 8.3 it looks like group by is faster. Tested it on a decent sized table and group by used a hash agg and ran in ~600 ms, while distinct used a sort and ran in 1300 ms. That was on 500k rows. On a much larger table, one with about 10M rows, a similar statement runs in 1500 ms with group by and in 2390 ms when run with distinct. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
