Thread: Re: [HACKERS] [COMMITTERS] pgsql: Add amcheck extension to contrib.

Andres Freund <andres@anarazel.de> writes:
> Add amcheck extension to contrib.

axolotl just failed on this:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=axolotl&dt=2017-03-13%2017%3A49%3A24

***************
*** 78,86 ****  -- make sure we don't have any leftover locks SELECT * FROM pg_locks WHERE relation IN
('bttest_a_idx'::regclass,'bttest_b_idx'::regclass); 
!  locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid |
virtualtransaction| pid | mode | granted | fastpath  
!
----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-----+------+---------+----------
! (0 rows)  COMMIT; -- cleanup
--- 78,87 ----  -- make sure we don't have any leftover locks SELECT * FROM pg_locks WHERE relation IN
('bttest_a_idx'::regclass,'bttest_b_idx'::regclass); 
!  locktype | database | relation | page | tuple | virtualxid | transactionid | classid | objid | objsubid |
virtualtransaction|  pid  |      mode       | granted | fastpath  
!
----------+----------+----------+------+-------+------------+---------------+---------+-------+----------+--------------------+-------+-----------------+---------+----------
!  relation |    57562 |    57573 |      |       |            |               |         |       |          | 4/29
       | 20342 | AccessShareLock | t       | t 
! (1 row)  COMMIT; -- cleanup


I could be wrong, but the most obvious explanation for this failure is
that autovacuum had a lock on the table or index when we looked.
Even if that isn't why axolotl failed in this particular case, I think
it's dead certain that we will see such failures from time to time
if this test script isn't tightened up.  IIUC what the test is trying
to look for, I think adding "AND pid = pg_backend_pid()" to this query
would be an appropriate fix.
        regards, tom lane

Hi,

On 2017-03-13 15:45:01 -0400, Tom Lane wrote:
> I could be wrong, but the most obvious explanation for this failure is
> that autovacuum had a lock on the table or index when we looked.
> Even if that isn't why axolotl failed in this particular case, I think
> it's dead certain that we will see such failures from time to time
> if this test script isn't tightened up.  IIUC what the test is trying
> to look for, I think adding "AND pid = pg_backend_pid()" to this query
> would be an appropriate fix.

Yes, that sounds reasonable.  Will do in a bit.  Thanks for noticing.

- Andres

On 2017-03-13 14:09:39 -0700, Andres Freund wrote:
> Hi,
> 
> On 2017-03-13 15:45:01 -0400, Tom Lane wrote:
> > I could be wrong, but the most obvious explanation for this failure is
> > that autovacuum had a lock on the table or index when we looked.
> > Even if that isn't why axolotl failed in this particular case, I think
> > it's dead certain that we will see such failures from time to time
> > if this test script isn't tightened up.  IIUC what the test is trying
> > to look for, I think adding "AND pid = pg_backend_pid()" to this query
> > would be an appropriate fix.
> 
> Yes, that sounds reasonable.  Will do in a bit.  Thanks for noticing.

Pushed.

- Andres