From: Tom Lane <tgl@sss.pgh.pa.us>
To: Elliot Chance <elliotchance@gmail.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: pg_dump and XID limit
Date: Wed, 24 Nov 2010 01:07:49 -0500
Message-ID: <6420.1290578869@sss.pgh.pa.us> (raw)
In-Reply-To: <DC1E3319-08CD-4C61-9565-06D744260261@gmail.com>
References: <DC1E3319-08CD-4C61-9565-06D744260261@gmail.com>
Elliot Chance <elliotchance@gmail.com> writes:
> This is a hypothetical problem but not an impossible situation. Just curious about what would happen.
> Lets say you have an OLTP server that keeps very busy on a large database. In this large database you have one or more tables on super fast storage like a fusion IO card which is handling (for the sake of argument) 1 million transactions per second.
> Even though only one or a few tables are using almost all of the IO, pg_dump has to export a consistent snapshot of all the tables to somewhere else every 24 hours. But because it's such a large dataset (or perhaps just network congestion) the daily backup takes 2 hours.
> Heres the question, during that 2 hours more than 4 billion transactions could of occurred - so what's going to happen to your backup and/or database?
The DB will shut down to prevent wraparound once it gets 2 billion XIDs
in front of the oldest open snaphot.
regards, tom lane
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-admin@postgresql.org
Cc: tgl@sss.pgh.pa.us, elliotchance@gmail.com
Subject: Re: pg_dump and XID limit
In-Reply-To: <6420.1290578869@sss.pgh.pa.us>
* 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