From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alexander Lakhin <exclusion@gmail.com>
cc: Victor Spirin <v.spirin@postgrespro.ru>,
        pgsql-hackers@lists.postgresql.org
Subject: Re: Sometimes the output to the stdout in Windows disappears
In-reply-to: <229665.1603044291@sss.pgh.pa.us>
References: <ac976d8c-03df-d6b8-025c-15a2de8d9af1@postgrespro.ru>
 <4124040.1598898684@sss.pgh.pa.us>
 <b92a7e09-9a60-d76b-e226-7e191fdc6f34@postgrespro.ru>
 <855416.1600022228@sss.pgh.pa.us>
 <ee02eaa2-03f7-74ea-bbdf-3196e506bae3@gmail.com>
 <4156857.1602865112@sss.pgh.pa.us>
 <b32688da-fafc-bbf6-b786-2dd7d0a4d578@gmail.com>
 <117919.1602949857@sss.pgh.pa.us> <132799.1602960277@sss.pgh.pa.us>
 <fca9beed-4902-d955-a691-96950fa54eaa@gmail.com>
 <229665.1603044291@sss.pgh.pa.us>
Comments: In-reply-to Tom Lane <tgl@sss.pgh.pa.us>
	message dated "Sun, 18 Oct 2020 14:04:51 -0400"
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-ID: <230798.1603045446.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Sun, 18 Oct 2020 14:24:06 -0400
Message-ID: <230799.1603045446@sss.pgh.pa.us>
Precedence: bulk

I wrote:
>> diff -w -U3
>> .../src/interfaces/ecpg/test/expected/thread-descriptor.stderr
>> .../src/interfaces/ecpg/test/results/thread-descriptor.stderr
>> --- .../src/interfaces/ecpg/test/expected/thread-descriptor.stderr=C2=A0=
=C2=A0=C2=A0
>> 2019-12-04 16:05:46 +0300
>> +++ .../src/interfaces/ecpg/test/results/thread-descriptor.stderr=C2=A0=
=C2=A0=C2=A0
>> 2020-10-18 20:20:27 +0300
>> @@ -0,0 +1 @@
>> +SQL error: descriptor "mydesc" not found on line 31

> does not look like the same kind of failure as what we've been dealing
> with up to now.  So maybe what we've got is that we fixed the stdio
> loss problem, and now the error rate is down to the point where we can
> notice other, even-lower-probability issues.

Yeah, I think so.  I grepped the buildfarm logs for similar failures and
found three occurrences:

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dbowerbird&dt=3D2=
019-02-03%2018%3A36%3A05
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dbowerbird&dt=3D2=
019-01-17%2014%3A30%3A07
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Ddrongo&dt=3D2020=
-01-02%2018%3A03%3A52

All of these are in the thread/descriptor test, failing at the deallocate
step in =


	for (i =3D 1; i <=3D REPEATS; ++i)
	{
		EXEC SQL ALLOCATE DESCRIPTOR mydesc;
		EXEC SQL DEALLOCATE DESCRIPTOR mydesc;
	}

where the test is running several of these in different threads.
I wonder whether there's some missing thread-locking in the ECPG
descriptor support.  It is odd though that we have seen this only
on Windows members.  Low-probability or not, you'd think we'd have
some similar reports from non-Windows critters if it were possible.

			regards, tom lane