Re: Potential autovacuum optimization: new tables - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Potential autovacuum optimization: new tables
Date
Msg-id 19389.1350158753@sss.pgh.pa.us
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In response to Re: Potential autovacuum optimization: new tables  (Joshua Berkus <josh@agliodbs.com>)
Responses Re: Potential autovacuum optimization: new tables  (Joshua Berkus <josh@agliodbs.com>)
List pgsql-hackers
Joshua Berkus <josh@agliodbs.com> writes:
> I've been going over the notes and email archives from the period
> where Matt O'Connor and I arrived at the current settings.  All of our
> testing was devoted to autovacuum, not autoanalyze.
> Our mistake was assuming that the same formula which worked well for
> vacuum would work well for analyze.

Ah.  Okay, maybe we can agree that that wasn't a good idea.

> So, problem #1 is coming up with a mathematical formula.  My initial target values are in terms of # of rows in the
tablevs. # of writes before analyze is triggered:
 

> 1 : 3
> 10 : 5
> 100 : 10
> 1000 : 100
> 100000 : 2000
> 1000000 : 5000
> 10000000 : 25000
> 100000000 : 100000

I don't really see that we need to bend over backwards to exactly match
some data points that you made up out of thin air.  How about
ceil(sqrt(N)) to start with?
        regards, tom lane



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