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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Tristan Partin <tristan@neon.tech>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org, Shlok Kyal <shlok.kyal.oss@gmail.com>
Subject: Re: psql not responding to SIGINT upon db reconnection
Date: Wed, 22 Nov 2023 23:00:03 +0200
Message-ID: <9b3693b7-0bc3-430a-b43f-eae44e8a39b6@iki.fi> (raw)
In-Reply-To: <CX5IOLTR8MAD.1UUDEG0X673Z4@neon.tech>
References: <CUAJJDVD8L61.2AH6VEEDMTXX3@gonk>
	<CUAKHCX5472I.SJP0AWQRYVFA@gonk>
	<CUAKIOVISECO.2S7MSQFOP1304@gonk>
	<1588058.1690220636@sss.pgh.pa.us>
	<CUAO24Z1Y72E.2069AD01EB4LO@gonk>
	<CANhcyEVBQWoPJK+C_h1CKyN3Wr2VKHuPx=bSB4PH2LuGdut4qg@mail.gmail.com>
	<CWRWDTTPP0WZ.2W75ZAVL5ND1M@neon.tech>
	<5e28b89f-0033-4e42-8184-b71b731c1aa2@iki.fi>
	<CX5IOLTR8MAD.1UUDEG0X673Z4@neon.tech>

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 v4
>>>>> 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 connection
>> is established or cancelled.
> 
> 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 
sure how portable that is. See signal(7) man page, section "Interruption 
of system calls and library functions by signal handlers". You could 
also use a timeout like 5 s to ensure that you wake up and notice that 
the signal was received eventually, even if it doesn't interrupt the 
blocking call.

-- 
Heikki Linnakangas
Neon (https://neon.tech)






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