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* How to find calculated CRC checksum of pg_controldata
@ 2014-04-03 13:58 Matthew Rantala <mjrantal@umn.edu>
2014-04-09 16:44 ` Re: How to find calculated CRC checksum of pg_controldata Bruce Momjian <bruce@momjian.us>
0 siblings, 1 reply; 3+ messages in thread
From: Matthew Rantala @ 2014-04-03 13:58 UTC (permalink / raw)
To: pgsql-admin
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.
--
Matthew J Rantala, GISP
Minnesota Geological Survey
University of Minnesota
2642 University Ave.
St. Paul, MN 55114-1057
(612) 627-4780 x206
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^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: How to find calculated CRC checksum of pg_controldata
2014-04-03 13:58 How to find calculated CRC checksum of pg_controldata Matthew Rantala <mjrantal@umn.edu>
@ 2014-04-09 16:44 ` Bruce Momjian <bruce@momjian.us>
2014-04-10 17:38 ` Re: How to find calculated CRC checksum of pg_controldata Matthew Rantala <mjrantal@umn.edu>
0 siblings, 1 reply; 3+ messages in thread
From: Bruce Momjian @ 2014-04-09 16:44 UTC (permalink / raw)
To: Matthew Rantala <mjrantal@umn.edu>; +Cc: pgsql-admin
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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^ permalink raw reply [nested|flat] 3+ messages in thread
* Re: How to find calculated CRC checksum of pg_controldata
2014-04-03 13:58 How to find calculated CRC checksum of pg_controldata Matthew Rantala <mjrantal@umn.edu>
2014-04-09 16:44 ` Re: How to find calculated CRC checksum of pg_controldata Bruce Momjian <bruce@momjian.us>
@ 2014-04-10 17:38 ` Matthew Rantala <mjrantal@umn.edu>
0 siblings, 0 replies; 3+ messages in thread
From: Matthew Rantala @ 2014-04-10 17:38 UTC (permalink / raw)
To: pgsql-admin
On 4/9/2014 11:44 AM, Bruce Momjian wrote:
> 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?
> Did you try pg_resetxlog? That should set the checksum properly.
>
Thanks, Bruce
I think I actually tried that and while it did correct the checksum, I
think it also closed/finalized the first log file
(00000001000000000000001) and modified the checkpoint locations which
wasn't going to work in my recovery. There may be a way to avoid that by
passing the correct parameters, but I found digging into the source code
easier.
Thanks again,
Matt
--
Matthew J Rantala, GISP
Minnesota Geological Survey
University of Minnesota
2642 University Ave.
St. Paul, MN 55114-1057
(612) 627-4780 x206
--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin
^ permalink raw reply [nested|flat] 3+ messages in thread
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2014-04-03 13:58 How to find calculated CRC checksum of pg_controldata Matthew Rantala <mjrantal@umn.edu>
2014-04-09 16:44 ` Bruce Momjian <bruce@momjian.us>
2014-04-10 17:38 ` Matthew Rantala <mjrantal@umn.edu>
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