From: Gnanakumar <gnanam@zoniac.com>
To: 'Alvaro Herrera' <alvherre@commandprompt.com>
Cc: 'pgsql-admin' <pgsql-admin@postgresql.org>
Subject: Re: Autovacuum daemon internal handling
Date: Thu, 12 Aug 2010 10:26:34 +0530
Message-ID: <002401cb39da$bf04aec0$3d0e0c40$@com> (raw)
In-Reply-To: <1281539491-sup-7017@alvh.no-ip.org>
References: <001d01cb3913$0e5c8f60$2b15ae20$@com>
<1281539491-sup-7017@alvh.no-ip.org>
> in 8.2 "naptime" means "time to sleep after we finish a job". So even
> if the previous task takes an hour, it will still sleep a minute before
> doing another round. (Note that this setting has a different meaning in
> later releases).
I couldn’t understand the difference in meaning of "autovacuum_naptime" between 8.2 and later releases from the documentation. May be I'm not understanding/seeing the subtle difference in the documentation lines mentioned. I referred these 3 doc links:
http://www.postgresql.org/docs/8.2/interactive/runtime-config-autovacuum.htmlhttp://www.postgresql.org/docs/8.3/interactive/runtime-config-autovacuum.htmlhttp://www.postgresql.org/docs/8.4/interactive/runtime-config-autovacuum.html
8.2 doc says "Specifies the delay between activity rounds for the autovacuum daemon...."
8.3 & 8.4 doc says "Specifies the minimum delay between autovacuum runs on any given database....."
Can you please make me clear on this?
> If autovacuum cannot keep up with all the vacuumable tables, you're in
> trouble and should probably schedule vacuum externally. (This also
> changed in later releases).
Can you please point me to relevant documentation links on this change?
>> 2. The columns "last_autovaccum" and 'last_autoanalyze" in
>> pg_stat_user_tables shows the start time or end time of the operation?
> End time.
Is there any way to find out the start time of "last_autovaccum" and/or 'last_autoanalyze" for a given table in 8.2.3? So that I can isolate the tables that are taking too long time to complete vacuum and/or analyze and I can perform them externally if need.
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To: pgsql-admin@postgresql.org
Cc: gnanam@zoniac.com, alvherre@commandprompt.com
Subject: Re: Autovacuum daemon internal handling
In-Reply-To: <002401cb39da$bf04aec0$3d0e0c40$@com>
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