Date: Sun, 15 Mar 2020 05:01:50 -0500
From: Justin Pryzby <pryzby@telsasoft.com>
To: Andres Freund <andres@anarazel.de>
Cc: David Rowley <dgrowleyml@gmail.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	Tomas Vondra <tomas.vondra@2ndquadrant.com>,
	Amit Kapila <amit.kapila16@gmail.com>,
	Masahiko Sawada <sawada.mshk@gmail.com>,
	Darafei =?utf-8?Q?Kom=D1=8Fpa?= Praliaskouski <me@komzpa.net>,
	pgsql-hackers@lists.postgresql.org,
	Alvaro Herrera <alvherre@2ndquadrant.com>,
	Michael Banck <mbanck@gmx.net>
Subject: Re: Berserk Autovacuum (let's save next Mandrill)
Message-ID: <20200315100150.GB26184@telsasoft.com>
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On Fri, Mar 13, 2020 at 02:38:51PM -0700, Andres Freund wrote:
> > Having now played with the patch, I'll suggest that 10000000 is too high a
> > threshold.  If autovacuum runs without FREEZE, I don't see why it couldn't be
> > much lower (100000?) or use (0.2 * n_ins + 50) like the other autovacuum GUC.
> 
> ISTM that the danger of regressing workloads due to suddenly repeatedly
> scanning huge indexes that previously were never / rarely scanned is
> significant

You're right - at one point, I was going to argue to skip index cleanup, and I
think wrote that before I finished convincing myself why it wasn't ok to skip.

-- 
Justin