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Date: Wed, 22 Nov 2023 15:29:45 -0600
Message-Id: <CX5NSE8R07D8.9D8M8LBKP119@neon.tech>
From: "Tristan Partin" <tristan@neon.tech>
Cc: "Tom Lane" <tgl@sss.pgh.pa.us>, <pgsql-hackers@postgresql.org>, "Shlok
 Kyal" <shlok.kyal.oss@gmail.com>
Subject: Re: psql not responding to SIGINT upon db reconnection
To: "Heikki Linnakangas" <hlinnaka@iki.fi>
References: <CUAJJDVD8L61.2AH6VEEDMTXX3@gonk>
 <CUAKHCX5472I.SJP0AWQRYVFA@gonk> <CUAKIOVISECO.2S7MSQFOP1304@gonk>
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 <CWRWDTTPP0WZ.2W75ZAVL5ND1M@neon.tech>
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 <9b3693b7-0bc3-430a-b43f-eae44e8a39b6@iki.fi>
In-Reply-To: <9b3693b7-0bc3-430a-b43f-eae44e8a39b6@iki.fi>
Archived-At: 
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On Wed Nov 22, 2023 at 3:00 PM CST, Heikki Linnakangas wrote:
> On 22/11/2023 19:29, Tristan Partin wrote:
> > On Thu Nov 16, 2023 at 8:33 AM CST, Heikki Linnakangas wrote:
> >> On 06/11/2023 19:16, Tristan Partin wrote:
> >>>>> That sounds like a much better solution. Attached you will find a v=
4
> >>>>> that implements your suggestion. Please let me know if there is
> >>>>> something that I missed. I can confirm that the patch works.
> >>
> >> This patch is missing a select(). It will busy loop until the connecti=
on
> >> is established or cancelled.
> >=20
> > If I add a wait (select, poll, etc.), then I can't control-C during the
> > blocking call, so it doesn't really solve the problem.
>
> Hmm, they should return with EINTR on signal. At least on Linux; I'm not=
=20
> sure how portable that is. See signal(7) man page, section "Interruption=
=20
> of system calls and library functions by signal handlers". You could=20
> also use a timeout like 5 s to ensure that you wake up and notice that=20
> the signal was received eventually, even if it doesn't interrupt the=20
> blocking call.

Ha, you're right. I had this working yesterday, but convinced myself it=20
didn't. I had a do while loop wrapping the blocking call. Here is a v4,=20
which seems to pass the tests that were pointed out to be failing=20
earlier.

Noticed that I copy-pasted pqSocketPoll() into the psql code. I think=20
this may be controversial. Not sure what the best solution to the issue=20
is. I will pay attention to the buildfarm animals when they pick this=20
up.

--=20
Tristan Partin
Neon (https://neon.tech)

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