Re: [COMMITTERS] pgsql: Change the way that LWLocks for extensions are allocated.

On Sat, Aug 27, 2016 at 3:30 AM, Andres Freund <andres(at)anarazel(dot)de> wrote:
> Hi,
>
> On 2016-02-04 21:43:14 +0000, Robert Haas wrote:
>> Change the way that LWLocks for extensions are allocated.
>>
>> The previous RequestAddinLWLocks() method had several disadvantages.
>> First, the locks would be in the main tranche; we've recently decided
>> that it's useful for LWLocks used for separate purposes to have
>> separate tranche IDs. Second, there wasn't any correlation between
>> what code called RequestAddinLWLocks() and what code called
>> LWLockAssign(); when multiple modules are in use, it could become
>> quite difficult to troubleshoot problems where LWLockAssign() ran out
>> of locks. To fix, create a concept of named LWLock tranches which
>> can be used either by extension or by core code.
>>
>> Amit Kapila and Robert Haas
>
> I noticed that this code has no test coverage:
>
> http://coverage.postgresql.org/src/backend/storage/lmgr/lwlock.c.gcov.html
>
> It'd be good to add some, although I'm not entirely sure what the best
> way is. Maybe add a simple pg_stat_statements test?

That would also have the advantage of improving the test coverage for
pg_stat_statements, which is at the moment quite a bit thinner than
the coverage for lwlock.c.

--
Robert Haas
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