Re: random system table corruption ...

Tom Lane wrote:
> =?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <postgres(at)cybertec(dot)at> writes:
>
>>in the past we have faced a couple of problems with corrupted system
>>tables. this seems to be a version independent problem which occurs on
>>hackers' from time to time.
>>i have checked a broken file and i have seen that the corrupted page has
>>actually been zeroed out.
>
>
> That sounds to me like a hardware problem --- disk or disk controller
> momentarily writing zeroes instead of what it should write. Have you
> seen this on more than one physical machine? Do you have any evidence
> for the implication that it only happens to system tables and not user
> tables?
>
> Also, you don't have zero_damaged_pages turned on by any chance?
>
> regards, tom lane

tom,

well, there is some evidence that this is not a hardware related issue.
we have only seen this problem from time to time but it happened on
different machines. it cannot be reproduced. it can even happen when
somebody runs a script which has been called million times before.
in my current scenario the page header only consists of 0x00 bytes and
therefore the page checks fails when reading the system table.

i have never seen this in data files up to now (at least not when the
hardware was still intact).

did anybody face similar problems? maybe on sun?
by the way: currently the broken system is running PostgreSQL 7.4 but as
I said - we have also seen that on 8.0 once.

best regards,

hans

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