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