Re: psql not responding to SIGINT upon db reconnection

Heikki Linnakangas <hlinnaka@iki.fi>

From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Tristan Partin <tristan@neon.tech>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org, Shlok Kyal <shlok.kyal.oss@gmail.com>
Date: 2023-11-22T21:00:03Z
Lists: pgsql-hackers
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)




Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. Fix old, misleading comment for PGRES_POLLING_ACTIVE.

  2. Remove reachable call to pg_unreachable().

  3. Allow SIGINT to cancel psql database reconnections.

  4. Expose PQsocketPoll via libpq

  5. Fix query cancellation handling in psql