"Mike Charnoky" <noky@nextbus.com> writes:
> I altered the table in question, with "set statistics 100" on the
> timestamp column, then ran analyze. This seemed to help somewhat. Now,
> queries don't seem to hang, but it still takes a long time to do the count:
> * "where evtime between '2007-09-26' and '2007-09-27'"
> took 37 minutes to run (result was ~12 million)
> * "where evtime between '2007-09-25' and '2007-09-26'"
> took 40 minutes to run (result was ~14 million)
>
> Still stymied about the seemingly random performance, especially since I
> have seen this query execute in 2 minutes.
And the "explain analyze" for these?
Are you still sure it's certain date ranges which are consistently problems
and others are consistently fast? Or could it be something unrelated.
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
