Horton

Re: Thread-unsafe coding in ecpg

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andrew Dunstan <andrew@dunslane.net>, "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>, Michael Meskes <meskes@postgresql.org>, "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Date: 2019-01-21T20:21:50Z
Lists: pgsql-hackers 
Hi,

On 2019-01-21 15:05:23 -0500, Tom Lane wrote:
> Andres Freund <andres@anarazel.de> writes:
> > Seems jacana might not have like this change?
> > https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=jacana&dt=2019-01-21%2019%3A01%3A28
> 
> Hmm.  So mingw doesn't provide access to _configthreadlocale().
> That's unfortunate, at least if we think that mingw is still a viable
> production platform, because it means we can't make ecpg thread-safe
> on that platform.
> 
> Is there a newer version of mingw that does have this functionality?
> I'm not sure whether to install a version check or just assume that
> it's never there.

It does seem like newer versions do have it:
https://sourceforge.net/p/mingw-w64/mailman/message/34765722/
https://sourceforge.net/p/mingw-w64/mingw-w64/ci/master/tree/mingw-w64-crt/misc/_configthreadlocale.c

We could just refuse to support thread safety on mingw if that's not
supported? Or is that too aggressive?

Greetings,

Andres Freund

Commits

  1. Remove _configthreadlocale() calls in ecpg test suite.

  2. Remove infinite-loop hazards in ecpg test suite.

  3. Blind attempt to fix _configthreadlocale() failures on MinGW.

  4. Avoid thread-safety problem in ecpglib.

  5. Second try at fixing ecpglib thread-safety problem.