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Date: Fri, 13 May 2011 10:44:47 +0200
Subject: Re: [ADMIN] since when has pg_stat_user_indexes.idx_scan
	been counting?
From: tv@fuzzy.cz
To: "Greg Smith" <greg@2ndquadrant.com>
Cc: "Tomas Vondra" <tv@fuzzy.cz>,
 pgsql-performance@postgresql.org
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> It's not synchronous at all.  The clients create a temporary file for
> the statistics collector and move on.  The actual statistics don't get
> updated until the statistics collector decides enough time has passed to
> bother, which defaults to at most every 500ms.

Really? I thought the clients send the updates using a socket, at least
that's what I see in backend/postmaster/pgstat.c (e.g. in
pgstat_send_bgwriter where the data are sent, and in PgstatCollectorMain
where it's read from the socket and applied).

But no matter how exactly this works, this kind of stats has nothing to do
with ANALYZe - it's asynchronously updated every time you run a query.

regards
Tomas