From: | Josh Berkus <josh(at)agliodbs(dot)com> |
---|---|
To: | Greg Stark <gsstark(at)mit(dot)edu> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, David Fetter <david(at)fetter(dot)org>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: More thoughts about planner's cost estimates |
Date: | 2006-06-02 22:15:43 |
Message-ID: | 200606021515.44174.josh@agliodbs.com |
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Lists: | pgsql-hackers |
Greg, Tom,
> But for most users analyze doesn't really have to run as often as
> vacuum. One sequential scan per night doesn't seem like that big a deal
> to me.
Clearly you don't have any 0.5 TB databases.
> > I'd still be worried about the CPU pain though. ANALYZE can afford to
> > expend a pretty fair number of cycles per sampled tuple, but with a
> > whole-table sample that's going to add up.
Agreed. Despite conventional wisdom, most PostgreSQL databases ... even
those with high level OLTP or very large DW ... are CPU-bound. We
really don't want an ANALYZE which is an order-of-magnitude increase in
CPU activity.
--
--Josh
Josh Berkus
PostgreSQL @ Sun
San Francisco
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