Re: Vacuumdb error - corruption

Hi Tom,

We recreated the index and that fixed it last week. We also had similar
failure few days back on a table but fortunately we had the luxury of
recreating it as the data was not so important, so we survived.
Yesterday we upgraded our postgres databases to 8.0.15 as suggested and
again we got error while vacuum analayze was run on the database and
this time it is on a different database and different table. I am not
able to access the table in question. Here is the error I get while
accessing the table. How do we recover this table from the error.

ectest=# select count(*) from securityevent;
ERROR: could not access status of transaction 33554431
DETAIL: could not open file "/pgdata/ec/data/pg_clog/001F": No such
file or directory

Error in the database vacuum log.
INFO: vacuuming "public.securityevent"
WARNING: relation "securityevent" TID 21/3: OID is invalid
vacuumdb: vacuuming of database "ectest" failed: ERROR: could not
access status of transaction 33554431
DETAIL: could not open file "/pgdata/ec/data/pg_clog/001F": No such
file or directory

Here are the machine specifics on which this database is running:
Platform: Linux x86_64
OS: Red Hat Enterprise Linux ES release 4 Kernel version: 2.6.9-34

According to our sysadmin there are no bad disks on the emc storage. So
what do you suggest we should do to narrow out the problem. Any help
will be highly appreciated. I have looked into the postgres archives and
people have reported this problem but there were no responses as to how
they resolved this issue. Do you still think it is due to block
corruption on disk? Please advice.

Thanks
Paramjeet Kaur

-----Original Message-----
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Thursday, April 17, 2008 5:18 PM
To: Bhella Paramjeet-PFCW67
Cc: pgsql-admin(at)postgresql(dot)org; Subbiah Stalin-XCGF84
Subject: Re: [ADMIN] Vacuumdb error

"Bhella Paramjeet-PFCW67" <PBhella(at)Motorola(dot)com> writes:
> We have our production postgres 8.0.10 database running on linux
> x86_64 machine. Recently we have started getting an error from one of
> our database while running vacuumdb. We are not getting this error
> during backups just only during vacuuming of a database. Can anyone
> please help us figure out why we are getting this error and how we can

> get rid of it. Any help will be appreciated.

> Here is the error:
> tst_021 ERROR: invalid page header in block 8 of relation
> "securityevent_pkey"

Well, since it's just an index, you should be able to fix it by
reindexing. But I'd worry a bit about what caused the corruption.
8.0.10 is not exactly current --- you should update to 8.0.latest.
And running some memory and disk diagnostics might not be wasted effort.

regards, tom lane