| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Don Bowman <don(at)sandvine(dot)com>, "'pgsql-performance(at)postgresql(dot)org'" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: not using index for select min(...) |
| Date: | 2003-01-31 23:31:12 |
| Message-ID: | 200301311531.12605.josh@agliodbs.com |
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| Lists: | pgsql-hackers pgsql-performance |
Don,
> I have a table which is very large (~65K rows). I have
> a column in it which is indexed, and I wish to use for
> a join. I'm finding that I'm using a sequential scan
> for this when selecting a MIN.
Due to Postgres' system of extensible aggregates (i.e. you can write your own
aggregates), all aggregates will trigger a Seq Scan in a query. It's a
known drawrback that nobody has yet found a good way around.
--
-Josh Berkus
Aglio Database Solutions
San Francisco
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