Re: Auto-analyse on insert operations

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Bertrand Roos <bertrand(dot)roos(at)areal(dot)fr>
Cc: Bill Moran <wmoran(at)potentialtech(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Auto-analyse on insert operations
Date: 2015-11-04 15:56:10
Message-ID: 3051.1446652570@sss.pgh.pa.us
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Bertrand Roos <bertrand(dot)roos(at)areal(dot)fr> writes:
> In fact, I was telling the question because I have read on some forums
> that the auto vacuum deamon only count dead tuple so only update and
> delete operations can cause the scheduling of auto-analyse.

That might have been true years ago, don't remember at the moment.
But in modern PG versions auto-vacuum is driven by the estimated number
of dead tuples while auto-analyze is driven by the total count of
inserts+updates+deletes. It's easy to show in a standalone experiment
that auto-analyze *will* run against a table that's only had inserts.

With the numbers you're showing, auto-analyze should trigger once the
table gets to 20% new tuples. It would be interesting to see the
pg_stat_all_tables values for one of your problematic tables.

regards, tom lane

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