From: Tom Lane <tgl@sss.pgh.pa.us>
To: mark@inomial.com
cc: pgsql-docs@postgresql.org
Subject: Re: Prepare transaction doesn't mention NOTIFY
In-reply-to: <20171024010602.1488.80066@wrigleys.postgresql.org>
References: <20171024010602.1488.80066@wrigleys.postgresql.org>
Comments: In-reply-to mark@inomial.com
	message dated "Tue, 24 Oct 2017 01:06:02 -0000"
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Date: Fri, 27 Oct 2017 10:59:00 -0400
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mark@inomial.com writes:
> Hi, in prepare transaction documentation in PG10 and earlier, it says that
> you can't prepare a transaction with LISTEN or UNLISTEN but it doesn't
> mention NOTIFY.

Yup, that's an oversight --- fixed.

> I know this isn't the place to ask (and I'll never see the answer :) but I'm
> baffled by the lack of support for NOTIFY in prepared transactions,

The big problem is that we can't do anything at PREPARE time to guarantee
that the NOTIFY will succeed.  Admittedly, the queue is large enough that
failure to insert the message isn't too likely, but "probably it will
work" is not the semantics we want from PREPARE.

			regards, tom lane


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