From: Michael Riess <mlriess@gmx.de>
To: pgsql-performance@postgresql.org
Subject: Re: Autovacuum / full vacuum
Date: Tue, 17 Jan 2006 16:04:41 +0100
Message-ID: <dqj121$3jm$1@news.hub.org> (raw)
In-Reply-To: <20060117145649.GE21092@phlogiston.dyndns.org>
References: <dqigaf$1b98$1@news.hub.org>
<20060117145649.GE21092@phlogiston.dyndns.org>
Hi,
>> hi,
>>
>> I'm curious as to why autovacuum is not designed to do full vacuum. I
>
> Because nothing that runs automatically should ever take an exclusive
> lock on the entire database, which is what VACUUM FULL does.
I thought that vacuum full only locks the table which it currently
operates on? I'm pretty sure that once a table has been vacuumed, it can
be accessed without any restrictions while the vacuum process works on
the next table.
>
>> activity. Increasing the FSM so that even during these bursts most space
>> would be reused would mean to reduce the available memory for all
>> other database tasks.
>
> I don't believe the hit is enough that you should even notice it.
> You'd have to post some pretty incredible use cases to show that the
> tiny loss of memory to FSM is worth (a) an exclusive lock and (b) the
> loss of efficiency you get from having some preallocated pages in
> tables.
I have 5000 tables and a workstation with 1 GB RAM which hosts an Apache
Web Server, Tomcat Servlet Container and PostgreSQL. RAM is not
something that I have plenty of ... and the hardware is fixed and cannot
be changed.
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: mlriess@gmx.de
Subject: Re: Autovacuum / full vacuum
In-Reply-To: <dqj121$3jm$1@news.hub.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox