Message-ID: <4BBCC51A.8090407@2ndquadrant.com>
Date: Wed, 07 Apr 2010 13:47:06 -0400
From: Greg Smith <greg@2ndquadrant.com>
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To: Renato Oliveira <renato.oliveira@grant.co.uk>
CC: pgsql-admin <pgsql-admin@postgresql.org>
Subject: Re: turn pitr 'on' on PostgreSQL 8.2 - pg_standby
References: <7965A9DCF12CC14984420BCC37B1608F25ABF310AB@Elzar.grant.co.uk>
In-Reply-To: <7965A9DCF12CC14984420BCC37B1608F25ABF310AB@Elzar.grant.co.uk>
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Renato Oliveira wrote:
>
> What is the difference between:
>
> archive_command = on (is this command for 8.2?)
>
> |archive_mode = on (This one is for 8.3!)|
>

8.2 doesn't have a archive_mode setting, that was added in 8.3. With 
8.2, you set the archive_command in the same way as you do in 8.3. There 
just isn't a dedicated parameters to toggle archiving on and off that's 
separate from changing the command used.

> |In order to bring the standby online I need a trigger file, something 
> like:|
>
> |can I call the trigger file whatever I want? for example; 
> ‘/var/log/postgres/postgresql.8.2.trigger’|
>

It doesn't matter where the trigger file is at so long as you use it 
correctly.

The other thing to be careful of, that you already noted, is that since 
8.2 doesn't ship with pg_standby, you need to grab your version of that. 
You should try to use the one that ships with 8.4. Also, it's not going 
to support the "%r" syntax in the restore_command, so you need to set 
the "-k" setting to a moderately high value for 8.2 servers. It's 
difficult to say exactly how high that must be for any possible 
workload. Something like "-k 256" is a reasonable starter setting that 
will save the last 4GB of archive logs shipped over on the standby, 
which is high enough to make deleting one of them prematurely unlikely 
(but not impossible for the right difficult workload).

-- 
Greg Smith  2ndQuadrant US  Baltimore, MD
PostgreSQL Training, Services and Support
greg@2ndQuadrant.com   www.2ndQuadrant.us