On Fri, Mar 14, 2003 at 14:19:46 -0600, Taral <[EMAIL PROTECTED]> wrote: > Same setup, different query: > > test=> explain select max(time) from test where id = '1'; > NOTICE: QUERY PLAN: > > Aggregate (cost=5084.67..5084.67 rows=1 width=0) > -> Index Scan using idx on test (cost=0.00..5081.33 rows=1333 width=0) > > Since the index is (id, time), why isn't the index being used to > retrieve the maximum value?
It looks like an index scan is being done. If the index was on (time, id) instead of (id, time), then you could get a further speed up by rewriting the query as: select time from test where id = '1' order by time desc limit 1; ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html
