Re: Speeding up SELECT MAX(),... GROUP BY ... ?

Chris,

> EXPLAIN
> select max(timepoint),lid,mid,sid from onfvalue
> where timepoint <= '2002-05-01 08:00:00' and sid in (1,3,5,7) group by
sid,lid,mid;

Having indexes on all four columns will help. Beyond that, there's not a lot
you can do; aggregate queries are slow. Rely on raw hardware power
(multi-channel SCSI, fast processor, lots of RAM and a very high sort_mem
setting).

BTW, if those four columns are the only data in the table, a Seq Scan is
actually the fastest method.

--
-Josh Berkus

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