Feedback-ID: ia2694551:Fastmail
Date: Sun, 4 Feb 2024 16:39:21 +0100
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Jelte Fennema-Nio <postgres@jeltef.nl>
Cc: vignesh C <vignesh21@gmail.com>, Thomas Munro <thomas.munro@gmail.com>,
	Denis Laxalde <denis.laxalde@dalibo.com>, Greg Stark <stark@mit.edu>,
 Tom Lane <tgl@sss.pgh.pa.us>,
	"Gregory Stark (as CFM)" <stark.cfm@gmail.com>,
 Jelte Fennema <Jelte.Fennema@microsoft.com>,
	Daniel Gustafsson <daniel@yesql.se>, Peter Eisentraut <peter@eisentraut.org>,
	Andres Freund <andres@anarazel.de>, Justin Pryzby <pryzby@telsasoft.com>,
	Robert Haas <robertmhaas@gmail.com>,
	"pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>
Subject: Re: [EXTERNAL] Re: Add non-blocking version of PQcancel
Message-ID: <202402041539.xv5n3pg2x57c@alvherre.pgsql>
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On 2024-Feb-02, Jelte Fennema-Nio wrote:

> The only reasonable thing I can think of to make that situation better
> is to move that part of the function outside of PQcancelPoll and
> create a dedicated PQcancelStart function for it. It introduces an
> extra function, but it does seem more in line with how we do the
> regular connection establishment. Basically you would have code like
> this then, which looks quite nice honestly:
> 
>     cancelConn = PQcancelConn(conn);
>     if (!PQcancelStart(cancelConn))
>         pg_fatal("bad cancel connection: %s", PQcancelErrorMessage(cancelConn));
>     while (true)
>     {
>          // polling using PQcancelPoll here
>     }

Maybe this is okay?  I'll have a look at the whole final situation more
carefully later; or if somebody else wants to share an opinion, please
do so.

In the meantime I pushed your 0002 and 0003 patches, so you can take
this as an opportunity to rebase the remaining ones.

-- 
Álvaro Herrera         PostgreSQL Developer  —  https://www.EnterpriseDB.com/
"The saddest aspect of life right now is that science gathers knowledge faster
 than society gathers wisdom."  (Isaac Asimov)