Re: Index Scans become Seq Scans after VACUUM ANALYSE - Mailing list pgsql-hackers

From mlw
Subject Re: Index Scans become Seq Scans after VACUUM ANALYSE
Date
Msg-id 3CBDE4C6.CFC1CC2D@mohawksoft.com
Whole thread Raw
In response to Re: Index Scans become Seq Scans after VACUUM ANALYSE  (mlw <markw@mohawksoft.com>)
Responses Re: Index Scans become Seq Scans after VACUUM ANALYSE  (Bruce Momjian <pgman@candle.pha.pa.us>)
List pgsql-hackers
Andrew Sullivan wrote:

> > Now, given the choice of the two strategies on a table, both pretty
> > close to one another, the risk of poor performance for using the
> > index scan is minimal based on the statistics, but the risk of poor
> > performance for using the sequential scan is quite high on a large
> > table.
> 
> I thought that's what the various cost estimates were there to cover.
> If this is all you're saying, then the feature is already there.

The point is that if the index plan is < 20% more costly than the sequential
scan, it is probably less risky.


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