Re: Why won't it index scan? - Mailing list pgsql-general

From Tom Lane
Subject Re: Why won't it index scan?
Date
Msg-id 15660.1148337802@sss.pgh.pa.us
Whole thread Raw
In response to Re: Why won't it index scan?  ("Jim C. Nasby" <jnasby@pervasive.com>)
Responses Re: Why won't it index scan?  (Alban Hertroys <alban@magproductions.nl>)
Re: Why won't it index scan?  (Ed Loehr <ed@loehrtech.com>)
Re: Why won't it index scan?  ("Jim C. Nasby" <jnasby@pervasive.com>)
List pgsql-general
"Jim C. Nasby" <jnasby@pervasive.com> writes:
> On Wed, May 17, 2006 at 10:29:14PM -0400, Tom Lane wrote:
>> The reason the default is currently 10 is just conservatism: it was
>> already an order of magnitude better than what it replaced (a *single*
>> representative value) and I didn't feel I had the evidence to justify
>> higher values.  It's become clear that the default ought to be higher,
>> but I've still got no good fix on a more reasonable default.  100 might
>> be too much, or then again maybe not.

> Is the only downside to a large value planning speed? It seems it would
> be hard to bloat that too much, except in cases where people are
> striving for millisecond response times, and those folks had better know
> enough about tuning to be able to adjust the stats target...

It would be nice to have some *evidence*, not unsupported handwaving.

            regards, tom lane

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