From: Bruce Momjian <bruce@momjian.us>
To: Matthew Rantala <mjrantal@umn.edu>
Cc: pgsql-admin@postgresql.org
Subject: Re: How to find calculated CRC checksum of pg_controldata
Date: Wed, 9 Apr 2014 12:44:55 -0400
Message-ID: <20140409164455.GC8686@momjian.us> (raw)
In-Reply-To: <533D6902.9080300@umn.edu>
References: <533D6902.9080300@umn.edu>
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On Thu, Apr 3, 2014 at 08:58:26AM -0500, Matthew Rantala wrote:
> Hello,
>
> Question: Is there a way to obtain the calculated CRC checksum for
> pg_controldata from the command line?
>
> I'm asking this because we had our database get wiped out, and for a
> variety of reasons, did not have a clean backup of the data
> directory. I did, however, have a complete set of WAL files for the
> database from the origin of the instance's life. I was able to use
> these to restore the database into a new database that I engineered
> look like a copy of the original by editing the pg_control file (and
> first log file) by changing the Database system identifier and the
> CRC checksum.
>
> Finding the correct CRC checksum, however, was a pain. I downloaded
> the code and modified pg_controldata.exe so it would display the
> file CRC and calculated checksums so I would know what the correct
> value was.
>
> I'm in the process of documenting what I did and it would make the
> whole process much easier if there is a way to determine the CRC
> checksum without having to dig into the source code. I am currently
> using 9.2.6.
>
> Thanks for any info,
>
> Matt, who was extremely lucky that I initiated WAL logging at the
> very beginning.
Did you try pg_resetxlog? That should set the checksum properly.
--
Bruce Momjian <bruce@momjian.us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
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To: pgsql-admin@postgresql.org
Cc: bruce@momjian.us, mjrantal@umn.edu
Subject: Re: How to find calculated CRC checksum of pg_controldata
In-Reply-To: <20140409164455.GC8686@momjian.us>
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