recovering a control file from a shutdown database....
Somehow in upgrading from 7.1.2 to 7.1.3 (and with much operator error
along the way), my database became corrupted.
I believe it is only the pg_control file that was damaged.
The database was completely shutdown at the time.
Is there anyway to create a new pg_control file, based on the contents of
the database itself?
The symptoms are that the
data/global/1262 file has a file size of 8192 bytes and a time stamp of
last June.
data/global/pg_control has a file size of 16384 bytes and a time stamp of
today.
When the postmaster starts up, it tells me that:
database was initialized with BLCKSZ 16384,
but the backend was compiled with BLCKSZ 8192.
looks like you need an initdb.
Bleh! I would prefer to not waste my db, and I assume initdb will do just
that.
Can anything be done to recover the pg_control file?
Thanks,
Jerry
========================================================
Jerry Asher jerry@theashergroup.com
1678 Shattuck Avenue Suite 161 Tel: (510) 549-2980
Berkeley, CA 94709 Fax: (877) 311-8688
When the postmaster starts up, it tells me that:
database was initialized with BLCKSZ 16384,
but the backend was compiled with BLCKSZ 8192.
looks like you need an initdb.
It sounds from that error message like your 7.1.2 version of PostgreSQL was
modified and compiled from source. The default BLCKSZ is 8192, which is what
your 7.1.3 version is using. I think you need to modify the BLCKSZ for 7.1.3
to match that of your database, and recompile, if you want to avoid losing
it.
See <postgres source tree>/src/include/config.h for the section that looks
like the following:
--------------------------------------------------------------
/*
* Size of a disk block --- this also limits the size of a tuple.
* You can set it bigger if you need bigger tuples (although TOAST
* should reduce the need to have large tuples, since fields can now
* be spread across multiple tuples).
*
* The maximum possible value of BLCKSZ is currently 2^15 (32768).
* This is determined by the 15-bit widths of the lp_off and lp_len
* fields in ItemIdData (see include/storage/itemid.h).
*
* CAUTION: changing BLCKSZ requires an initdb.
*/
#define BLCKSZ 8192
--------------------------------------------------------------
and change
#define BLCKSZ 8192
to
#define BLCKSZ 16384
Then recompile.
Hope this helps,
-- Joe
Jerry Asher <jerry@theashergroup.com> writes:
Can anything be done to recover the pg_control file?
I've already been talking to Jerry off-list, and I trust he's managed
to recover his data --- but for the archives, the answer to this is to
hack up contrib/pg_resetxlog to force whatever data you need into the
pg_control file.
It is an *extremely* good idea to back up your whole $PGDATA directory
tree (with tar or some such) before attempting such desperate measures,
so that you can undo any self-inflicted damage if you get it wrong...
regards, tom lane