Re: [HACKERS] Moving relation extension locks out of heavyweight lock manager

On Sun, Mar 15, 2020 at 1:15 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Sat, Mar 14, 2020 at 7:39 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Fri, Mar 13, 2020 at 7:02 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > >
> > > Apart from that, I have also extended the solution for the page lock.
> > > And, I have also broken down the 3rd patch in two parts for relation
> > > extension and for the page lock.
> > >
> >
> > Thanks, I have made a number of cosmetic changes and written
> > appropriate commit messages for all patches. See the attached patch
> > series and let me know your opinion? BTW, did you get a chance to test
> > page locks by using the extension which I have posted above or by some
> > other way? I think it is important to test page-lock related patches
> > now.
>
> I have reviewed the updated patches and looks fine to me. Apart from
> this I have done testing for the Page Lock using group locking
> extension.
>
> --Setup
> create table gin_test_tbl(i int4[]) with (autovacuum_enabled = off);
> create index gin_test_idx on gin_test_tbl using gin (i);
> create table gin_test_tbl1(i int4[]) with (autovacuum_enabled = off);
> create index gin_test_idx1 on gin_test_tbl1 using gin (i);
>
> --session1:
> select become_lock_group_leader();
> select gin_clean_pending_list('gin_test_idx');
>
> --session2:
> select become_lock_group_member(session1_pid);
> select gin_clean_pending_list('gin_test_idx1');
>
> --session3:
> select become_lock_group_leader();
> select gin_clean_pending_list('gin_test_idx1');
>
> --session4:
> select become_lock_group_member(session3_pid);
> select gin_clean_pending_list('gin_test_idx');
>
> ERROR: deadlock detected
> DETAIL: Process 61953 waits for ExclusiveLock on page 0 of relation
> 16399 of database 13577; blocked by process 62197.
> Process 62197 waits for ExclusiveLock on page 0 of relation 16400 of
> database 13577; blocked by process 61953.
> HINT: See server log for query details.
>
>
> Session1 and Session3 acquire the PageLock on two different index's
> meta-pages and blocked in gdb, meanwhile, their member tries to
> acquire the page lock as shown in the above example and it detects the
> deadlock which is solved after applying the patch.

I have modified 0001 and 0002 slightly, Basically, instead of two
function CheckAndSetLockHeld and CheckAndReSetLockHeld, I have created
a one function.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com