Horton

Re: On login trigger: take three

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Daniel Gustafsson <daniel@yesql.se>
Cc: Alexander Lakhin <exclusion@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>, Mikhail Gribkov <youzhick@gmail.com>, Michael Paquier <michael@paquier.xyz>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Greg Nancarrow <gregn4422@gmail.com>, Ivan Panchenko <wao@mail.ru>, Teodor Sigaev <teodor@sigaev.ru>, Ibrar Ahmed <ibrar.ahmad@gmail.com>, vignesh C <vignesh21@gmail.com>, Pavel Stehule <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, Amit Kapila <amit.kapila16@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>
Date: 2024-01-17T21:25:02Z
Lists: pgsql-hackers 
On Mon, Jan 15, 2024 at 11:29 AM Daniel Gustafsson <daniel@yesql.se> wrote:
> > On 13 Jan 2024, at 17:00, Alexander Lakhin <exclusion@gmail.com> wrote:
>
> > I suspected that this failure was caused by autovacuum, and I've managed to
> > reproduce it without Valgrind or slowing down a machine.
>
> This might be due to the fact that the cleanup codepath to remove the flag when
> there is no login event trigger doesn't block on locking pg_database to avoid
> stalling connections.  There are no guarantees when the flag is cleared, so a
> test like this will always have potential to be flaky it seems.

+1
Thank you, Daniel.  I think you described everything absolutely
correctly.  As I wrote upthread, it doesn't seem much could be done
with this, at least within a regression test.  So, I just removed this
query from the test.

------
Regards,
Alexander Korotkov

Commits

  1. Fix some typos in event trigger docs

  2. Use heap_inplace_update() to unset pg_database.dathasloginevt

  3. Remove the flaky check in event_trigger_login regression test

  4. Fix instable 006_login_trigger.pl test

  5. Add support event triggers on authenticated login

  6. Add GUC for temporarily disabling event triggers

  7. Fix typo in reference to __FreeBSD__.

  8. Restore robustness of TAP tests that wait for postmaster restart.

  9. Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.