Re: race condition for drop schema cascade?

Tom Lane wrote:

>Andrew Dunstan <andrew@dunslane.net> writes:
>  
>
>>You're right - my query was not sufficiently specific. There have in 
>>fact been 4 failures:
>>    
>>
>
>  
>
>>pgbuildfarm=# select sysname, snapshot, stage, branch from build_status 
>>where log ~ 'tablespace "testspace" is not empty.*tablespace "testspace" 
>>is not empty' and not log ~ 'No space left';
>> sysname |      snapshot       |    stage     | branch
>> --------+---------------------+--------------+--------
>> hare    | 2004-12-09 05:15:05 | Check        | HEAD
>> otter   | 2004-12-11 15:50:09 | Check        | HEAD
>> otter   | 2004-12-15 15:50:10 | Check        | HEAD
>> gibbon  | 2004-12-28 23:55:05 | InstallCheck | HEAD
>>    
>>
>
>Why does the last show as an "install" failure?
>  
>


We run the standard regression suite twice - the failure on Gibbon 
occurred on the second of these. Clearly this is very transient.


>Anyway, given the small number of machines involved, I'm once again
>wondering what filesystem they are using.  They wouldn't be running
>the check over NFS, by any chance, for instance?
>
>The theory that is in my mind is that the bgwriter could have written
>out a page for the table in the test tablespace, and thereby be holding
>an open file pointer for it.  On standard Unix filesystems this would
>not disrupt the backend's ability to unlink the table at the DROP stage,
>but I'm wondering about nonstandard filesystems ...
>
>  
>

Jim Buttafuoco reported on December 16th that he had rebuilt the 
filesystem on his MIPS box - I assume this means that he isn't using 
NFS. In any case, we have not seen the problem since then. His Alpha box 
has not been reporting buildfarm results since before then.

The Cygwin box is running on NTFS - and we know we've encountered plenty 
of problems with unlinking on Windows.

I know it's not much to go on.

cheers

andrew