Re: 9.2 pg_upgrade regression tests on WIndows

On 09/05/2012 09:42 PM, Bruce Momjian wrote:
> On Wed, Sep 5, 2012 at 09:07:05PM -0400, Andrew Dunstan wrote:
>>> OK, I worked with Andrew on this issue, and have applied the attached
>>> patch which explains what is happening in this case. Andrew's #ifndef
>>> WIN32 was the correct fix. I consider this issue closed.
>>>
>>
>> It looks like we still have problems in this area :-( see <http://www.pgbuildfarm.org/cgi-bin/show_log.pl?nm=pitta&dt=2012-09-05%2023%3A05%3A16>
>>
>> Now it looks like somehow the fopen on the log file that isn't
>> commented out is failing. But the identical code worked on the same
>> machine on HEAD. SO this does rather look like a timing issue.
>>
>> Investigating ...
> Yes, that is very odd. It is also right after the code we just changed
> to use binary mode to split the pg_dumpall file, split_old_dump().
>
> The code is doing pg_ctl -w stop, then starting a new postmaster with
> pg_ctl -w start. Looking at the pg_ctl.c code (that you wrote), what
> pg_ctl -w stop does is to wait for the postmaster.pid file to disappear,
> then it returns complete. I suppose it is possible that the pid file is
> getting removed, pg_ctl is returning done, but the pg_ctl binary is
> still running, holding open those log files.
>
> I guess the buildfarm is showing us the problems in pg_upgrade, as it
> should. I think you might be right that we need to add a sleep(1) at
> the end of stop_postmaster on Windows, and document it is to give the
> postmaster time to release its log files.

Icky. I wish there were some nice portable flock() mechanism we could use.

I just re-ran the test on the same machine, same code, same everything
as the reporte3d failure, and it passed, so it definitely looks like
it's a timing issue.

I'd be inclined to put a loop around that fopen() to try it once every
second for, say, 5 seconds.

cheers

andrew