Re: Clarification Needed: When does autovacuum daemon run?

From: "Narasimha Murthy-VRFX87" <VRFX87(at)motorola(dot)com>
To: "Alvaro Herrera" <alvherre(at)alvh(dot)no-ip(dot)org>
Cc: "Ian Lea" <ian(dot)lea(at)gmail(dot)com>, Devrim GÜNDÜZ <devrim(at)gunduz(dot)org>, "pgsql-admin" <pgsql-admin(at)postgresql(dot)org>
Subject: Re: Clarification Needed: When does autovacuum daemon run?
Date: 2010-05-20 06:47:21
Message-ID: 58FEF525AF1E664D9503ACDEAC926BBC03BE7D8D@ZMY16EXM66.ds.mot.com
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Hi Alvaro Herrera,

Since, my original plan was to run the auto-vacuum daily EXACTLY at 5 am, I wanted to know which seconds of a minute. My query in other word was, if I set autovacuum_naptime to 1 hr, which minute of an hour the auto-vacuum runs (oth min, 15th min or something else).

From the clarification given by the you and other community members, I now understood that autovacuum is designed to run frequently in the background, not designed to run once a day at a specific time. Due to this design intent, autovacuum_naptime is set to 1 min by default and autovacuum runs lazy/plain/standard vacuum commands (so that Vacuum can run concurrently with other normal DB operations).

Regards, Narasimha Murthy
Cell +91 95814 98895, +91-94940 62794 | 040-2347 2025 (O) | x2025 (O)

-----Original Message-----
From: pgsql-admin-owner(at)postgresql(dot)org [mailto:pgsql-admin-owner(at)postgresql(dot)org] On Behalf Of Alvaro Herrera
Sent: Thursday, May 20, 2010 2:21 AM
To: Narasimha Murthy-VRFX87
Cc: Ian Lea; Devrim GÜNDÜZ; pgsql-admin
Subject: Re: [ADMIN] Clarification Needed: When does autovacuum daemon run?

Excerpts from Narasimha Murthy-VRFX87's message of mar may 18 07:04:34 -0400 2010:

> I need some more clarification. autovacuum_naptime takes one minute by
> default. In this case, which second of each minute the autovacuum
> daemon runs (provided it is enabled)?

Why does it matter which second it runs?

> What is the "activity rounds" mentioned in the manual??

Each worker start is a new round.
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