From: Tom Lane <tgl@sss.pgh.pa.us>
To: Petr Jelinek <petr@2ndquadrant.com>
cc: Amit Langote <amitlangote09@gmail.com>,
        Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
        Rafia Sabih <rafia.pghackers@gmail.com>,
        PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: adding partitioned tables to publications
In-reply-to: <63961884-6d56-a12b-d3f5-9a5dcbcc37f4@2ndquadrant.com>
References: 
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 <CA+HiwqFZbbJzAZgTjqbRarp_xeqyymuNmGg8Q5tDKTZbk3=c2A@mail.gmail.com>
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 <CA+HiwqE+6gNgr-BVYeCMT38naRi9cJaanJb7+FCNsX9XgMwHsQ@mail.gmail.com>
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 <9684.1585929105@sss.pgh.pa.us> <63961884-6d56-a12b-d3f5-9a!
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Comments: In-reply-to Petr Jelinek <petr@2ndquadrant.com>
	message dated "Sat, 04 Apr 2020 07:07:29 +0200"
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Date: Sat, 04 Apr 2020 01:25:07 -0400
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Petr Jelinek <petr@2ndquadrant.com> writes:
> On 03/04/2020 17:51, Tom Lane wrote:
>> But the forked-off children have to write the gcov files independently,
>> don't they?

> Hmm that's very good point. I did see these missing coverage issue when 
> running tests that explicitly start more instances of postgres before 
> though. And with some quick googling, parallel testing seems to be issue 
> with gcov for more people.

I poked around and found this:

https://gcc.gnu.org/legacy-ml/gcc-help/2005-11/msg00074.html

which says

    gcov instrumentation is multi-process safe, but not multi-thread
    safe. The multi-processing safety relies on OS level file locking,
    which is not available on some systems.

That would explain why it works for me, but then there's a question
of why it doesn't work for you ...

			regards, tom lane