Horton

Re: logical replication and PANIC during shutdown checkpoint in publisher

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Petr Jelinek <petr.jelinek@2ndquadrant.com>, Fujii Masao <masao.fujii@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2017-06-01T23:38:51Z
Lists: pgsql-hackers 
On Fri, Jun 2, 2017 at 7:05 AM, Andres Freund <andres@anarazel.de> wrote:
> I'm a unhappy how this is reusing SIGINT for WalSndLastCycleHandler.
> Normally INT is used cancel interrupts, and since walsender is now also
> working as a normal backend, this overlap is bad.  Even for plain
> walsender backend this seems bad, because now non-superusers replication
> users will terminate replication connections when they do
> pg_cancel_backend().  For replication=dbname users it's especially bad
> because there can be completely legitimate uses of pg_cancel_backend().

Signals for WAL senders are set in WalSndSignals() which uses SIG_IGN
for SIGINT now in ~9.6, and StatementCancelHandler does not get set up
for a non-am_walsender backend. Am I missing something?
-- 
Michael

Commits

  1. Prevent possibility of panics during shutdown checkpoint.

  2. Revert "Prevent panic during shutdown checkpoint"

  3. Prevent panic during shutdown checkpoint