Horton

Re: NOTIFY does not work as expected

Andres Freund <andres@anarazel.de>

View thread View on postgr.es
From: Andres Freund <andres@anarazel.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Andrey <parihaaraka@gmail.com>, Jeff Janes <jeff.janes@gmail.com>, Pg Bugs <pgsql-bugs@postgresql.org>
Date: 2018-10-19T23:14:35Z
Lists: pgsql-bugs 
Hi,

On 2018-10-19 13:45:42 -0700, Andres Freund wrote:
> On 2018-10-19 13:36:31 -0400, Tom Lane wrote:
> > If we're willing to accept a ProcDie interrupt during secure_read at all,
> > I don't see why not to do it even if we got some data.  We'll accept the
> > interrupt anyway the next time something happens to do
> > CHECK_FOR_INTERRUPTS; and it's unlikely that that would not be till after
> > we'd completed the query, so the net effect is just going to be that we
> > waste some cycles first.
> 
> I don't immediately see a problem with changing this for reads.

One argument against changing it, although not a very strong one, is
that processing a proc die even when non-blocking prevents us from
processing commands like a client's X/terminate even if we already have
the necessary input.

Greetings,

Andres Freund

Commits

  1. Client-side fixes for delayed NOTIFY receipt.

  2. Server-side fix for delayed NOTIFY and SIGTERM processing.

  3. Introduce and use infrastructure for interrupt processing during client reads.