Re: [BUGS] BUG #14830: Missed NOTIFications, PostgreSQL 9.1.24 - Mailing list pgsql-bugs

From Marko Tiikkaja
Subject Re: [BUGS] BUG #14830: Missed NOTIFications, PostgreSQL 9.1.24
Date
Msg-id CAL9smLD0GFhpw+EB9EcEWvYFZ2p-qvhi5qSkJTHb32bUSi9UXg@mail.gmail.com
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In response to Re: [BUGS] BUG #14830: Missed NOTIFications, PostgreSQL 9.1.24  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-bugs
On Tue, Oct 10, 2017 at 3:58 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Marko Tiikkaja <marko@joh.to> writes:
> So I managed to accidentally kill and/or restart both servers while trying
> to install debug symbols, but I'm doing a new run now and I noticed
> something interesting: the listening backend's RecentXmin doesn't seem to
> ever go forward.  By my reading of this code, that would mean trouble for
> this piece of code in TransactionIdIsInProgress:

>   if (TransactionIdPrecedes(xid, RecentXmin))
>       return false;

Hmm ... I suppose it's possible that that happens if the listening
backend isn't executing any SQL commands but is just sitting.
While that might describe your test harness, does it describe any
real-world application?

Yes.  It's a service which only does LISTEN and UNLISTEN and forwards notifications to its clients.


.m

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