Horton

Re: pgsql: Improve autovacuum logging for aggressive and anti-wraparound ru

Alvaro Herrera <alvherre@2ndquadrant.com>

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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>
Date: 2018-09-24T21:11:17Z
Lists: pgsql-hackers 
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

Commits

  1. Skip redundant anti-wraparound vacuums

  2. Improve autovacuum logging for aggressive and anti-wraparound runs

  3. In relevant log messages, indicate whether vacuums are aggressive.

  4. Don't vacuum all-frozen pages.