Re: Re: Postgres slowdown on large table joins

On Mon, Feb 19, 2001 at 12:22:11PM -0500, Tom Lane wrote:
> Dave Edmondson <david(at)jlc(dot)net> writes:
> > Ack! I just timed it at 74 seconds.
> > Added two indexes, here's the query plan... it doesn't seem to be using the
> > indexes at all. I'm sure I'm doing something wrong here...
>
> Have you done a VACUUM ANALYZE on these tables since filling them?
> Are the estimated rows counts in the plan anywhere near reality? The
> rows=145972 for data looks particularly fishy ... how many rows of data
> do you think will match the conf_id extracted from config?
>
> regards, tom lane

yes. I ran VACUUM ANALYZE after creating the indicies. (Actually, I VACUUM
the database twice a day.) The data table literally has 145972 rows, and
145971 will match conf_id 4... which is why I'm getting the feeling that an
index on conf_id in data won't actually solve the problem (after reading
about what indicies actually do). I think I might just have split to the one
table join into separate queries, and ignore any entries before a certain
date/time... guess I'll just have to get creative for that part. :)

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David Edmondson <david(at)jlc(dot)net>
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