Date: Mon, 24 Sep 2018 18:11:17 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Sergei Kornilov <sk@zsrv.org>
Cc: "Nasby, Jim" <nasbyj@amazon.com>, Andres Freund <andres@anarazel.de>,
	Robert Haas <robertmhaas@gmail.com>,
	Michael Paquier <michael@paquier.xyz>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Improve autovacuum logging for aggressive and
 anti-wraparound ru
Message-ID: <20180924211117.tpwxemzd3372nagj@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <23209391537822541@iva4-6d7004ac8463.qloud-c.yandex.net>
User-Agent: NeoMutt/20180716
Precedence: bulk

On 2018-Sep-24, Sergei Kornilov wrote:

> Hi
> 
> > An autovacuum can't be just aggressive; it's either anti-wraparound or normal.
> But autovacuum _can_ be aggressive and not anti-wraparound.
> I build current master and can see 3 different line types:
> 2018-09-24 23:47:31.500 MSK 27939 @ from  [vxid:4/272032 txid:0] [] LOG:  automatic aggressive vacuum of table "postgres.public.foo": index scans: 0
> 2018-09-24 23:49:27.892 MSK 28333 @ from  [vxid:4/284297 txid:0] [] LOG:  automatic aggressive vacuum to prevent wraparound of table "postgres.public.foo": index scans: 0
> 2018-09-24 23:49:29.093 MSK 28337 @ from  [vxid:4/284412 txid:0] [] LOG:  automatic vacuum of table "postgres.public.foo": index scans: 0

Exactly.

It cannot be anti-wraparound and not aggressive, which is the line type
not shown.

"Aggressive" means it scans all pages; "anti-wraparound" means it does
not let itself be cancelled because of another process waiting for a
lock on the table.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services