| From: | Chris Browne <cbbrowne(at)acm(dot)org> |
|---|---|
| To: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: BUG #2658: Query not using index |
| Date: | 2006-10-03 19:18:36 |
| Message-ID: | 60d599gqcz.fsf@dba2.int.libertyrms.com |
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| Lists: | pgsql-bugs pgsql-performance |
gdavis(at)refractions(dot)net (Graham Davis) writes:
> 40 seconds is much too slow for this query to run and I'm assuming
> that the use of an index will make it much faster (as seen when I
> removed the GROUP BY clause). Any tips?
Assumptions are dangerous things.
An aggregate like this has *got to* scan the entire table, and given
that that is the case, an index scan is NOT optimal; a seq scan is.
An index scan is just going to be slower.
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