Re: WAL replay failure after file truncation(?)

Tom Lane wrote:
> =?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <postgres(at)cybertec(dot)at> writes:
>
>>My question is: What happens if the system is killed inside
>>rebuild_relation or inside swap_relfilenodes which is called by
>>rebuild_relation?
>
>
> Nothing at all, because the system catalog updates aren't committed yet,
> and we haven't done anything to the relation's old physical file.

This is actually what I expected.
I have gone through the code and it looks correct.
TRUNCATE is the only command in this application which can potentially
cause the problem (it is very unlikely that INSERT removes a file).

> If I were you I'd be looking into whether your disk hardware honors
> write ordering properly. This sounds like something allowed the
> directory change to reach disk before the transaction commit WAL record
> did; which is impossible if fsync is doing what it's supposed to.
>
> regards, tom lane

We are on sun Solaris (x86) box here. I am not sure what Sun has
corrupted to make this error happen. Obviously it happens only once per
1.000.000 tries ...
I am just trying to figure out whether the bug could potentially be
inside PostgreSQL. It would have been surprised if somebody had overseen
a problem like that.

many thanks and best regards,

Hans

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