Re: Data corruption zero a file - help!!

On Wed, Mar 01, 2006 at 04:12:53PM +1100, Noel Faux wrote:
> Now after doing some searches I managed to work out that the data
> corruption starts at 902292.137
> using this sql:
> SELECT * FROM gap WHERE ctid = '(902292,$x)'
> Where $x I changed from 1-150.
>
> as mentioned on this
> post:http://archives.postgresql.org/pgsql-general/2005-11/msg01148.php
>
> Following this post it seems all we need to do is re-zero from this
> point on. However we're not sure which file to do this in.

This earlier message in that thread should be helpful:

http://archives.postgresql.org/pgsql-general/2005-11/msg01141.php

> I've worked out the database/relation files are
> $PGDATA/37958/111685332.* with the max * being 101.

Is your table really over 100G? Anyway, if the block size is 8192
then 902292 sould be in the .6 file. If you can spare the time
then you might run the dd and od commands that Tom Lane mentions
in the above message and post the output. I think the command would
be

dd bs=8k skip=115860 count=1 if=$PGDATA/37958/111685332.6 | od -x

See Tom's message for how I arrived at .6 and 115860 (and verify
the math yourself).

--
Michael Fuhr