Skip site navigation (1) Skip section navigation (2)

Re: pg_start_backup and pg_stop_backup Re: Re: [COMMITTERS] pgsql: Make CheckRequiredParameterValues() depend upon correct

From: Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>
To: Simon Riggs <simon(at)2ndQuadrant(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, Fujii Masao <masao(dot)fujii(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: pg_start_backup and pg_stop_backup Re: Re: [COMMITTERS] pgsql: Make CheckRequiredParameterValues() depend upon correct
Date: 2010-04-28 18:49:20
Message-ID: 4BD88330.4030006@enterprisedb.com (view raw or flat)
Thread:
Lists: pgsql-hackers
Simon Riggs wrote:
> On Wed, 2010-04-28 at 14:21 -0400, Tom Lane wrote:
>> Is there any use in looking
>> at wal_keep_segments as part of this test?
> 
> I would hope that pg_stop_backup() will have a conditional ERROR message
> to say
> 
> ERROR backup inconsistent and cannot be used for SR
> HINT increase wal_keep_segments or enable archiving for your base backup

Hmm, you could start streaming the WAL before you start the backup, so
the fact that you've already removed some segments that are needed to
restore from the backup by the time pg_stop_backup() is called doesn't
necessarily mean that the backup is useless.

You'd need a stand-alone tool to do the streaming in that case, and no
such tool exists yet, but I would be surprised if one doesn't appear on
pgfoundry sooner or later :-).

In case it's not clear to casual readers out there:
You will get an error as soon as you try to start the standby,
complaining that it can't find the WAL segment it needs in the primary
anymore. Not silent corruption.

-- 
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

In response to

Responses

pgsql-hackers by date

Next:From: Greg StarkDate: 2010-04-28 18:54:53
Subject: Re: Differential backup
Previous:From: Kevin GrittnerDate: 2010-04-28 18:39:28
Subject: Re: explicit (void *) casts

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group