Re: WAL replay failure after file truncation(?)

Tom Lane wrote:
> =?ISO-8859-1?Q?Hans-J=FCrgen_Sch=F6nig?= <postgres@cybertec.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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