From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: Michael Nacos <m.nacos@gmail.com>
To: pgsql-admin@postgresql.org
Subject: Re: How do i compare 2 postgresql instanses ?
Date: Tue, 08 Jul 2008 09:28:14 -0500
Message-ID: <4873335D.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <407fa4640807080620r33a3463fgff195d8ae5ef708e@mail.gmail.com>
References: <49982.1215520948@ismartpanache.com>
<200807081602.39336.achill@matrix.gatewaynet.com>
<407fa4640807080620r33a3463fgff195d8ae5ef708e@mail.gmail.com>
>>> "Michael Nacos" <m.nacos@gmail.com> wrote:
> what if you actually want to look at the data? I have been
> thinking about row checksums, would you say this would be a
reasonable way
> of verifying two databases are equivalent?
Our home-grown replication technique does synchronization checks
during idle time. It works pretty well for us, and we do use md5sum
techniques to minimize bandwidth.
In summary, a process requests a middle tier on a "source" machine to
send "sync" information; that middle tier reads some set of rows and
sends the md5 sum of all data in the rows, along with information on
what rows from which table were used to develop the number. The
requesting process then asks similar middle tiers on all replication
targets to return their md5sum for the same set of rows. If there are
any differences, the source and all differing replication targets are
queried for the actual values, which are compared using match-merge
type logic on the primary key sequence.
Something similar might work for you.
-Kevin
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: Kevin.Grittner@wicourts.gov, m.nacos@gmail.com
Subject: Re: How do i compare 2 postgresql instanses ?
In-Reply-To: <4873335D.EE98.0025.0@wicourts.gov>
* 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