Re: Various serverlog messages

If an IDE drive has a bad block, doesn't it just mark the block as bad
and map in a new one, perhaps taking as much of the old block as it can?
Maybe that is the cause.

From my experience, SCSI reports a block error and will not read it.

---------------------------------------------------------------------------

Tom Lane wrote:
> CSN <cool_screen_name90001@yahoo.com> writes:
> > Yes, pg_dump and pg_dumpall appear to work fine. The
> > output for all of the dbs (except one) for the select
> > above is:
> > [ normal looking ]
> > Here's the exception:
>
> >  16656 | pg_toast_16384_index |           99 |       0
> > |        1 |   403 |  3682590432 |        1 |
> > 0 |             0 |             0 | f           | f
> >        | i       |        2 |         0 |           0
> > |        0 |        0 |       0 | f          | f
> >    | f           | f              |
> > (1 row)
>
> Sure enough, the relfilenode column (which determines the actual on-disk
> filename) is clobbered.  Weird as can be ... could you have suffered a
> hardware glitch affecting just that one word?  Doesn't seem real likely
> --- the glitches I've seen in the past tend to take out more than a word
> at a time.  But it's not easy to credit as a software error either.
>
> You could fix this database with a quick UPDATE command to set
> relfilenode back to what it should be in this pg_class row.  However,
> it'd be wise to wonder what other issues might be lurking.  If I were
> you I'd do a pg_dumpall/initdb/reload cycle, and also spend some time on
> hardware testing (if you're on Intel hardware, memtest86 has a good
> reputation for finding RAM problems, and people have successfully found
> disk problems with badblocks).
>
>             regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
>                http://archives.postgresql.org
>

--
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073