Horton

Re: A new function to wait for the backend exit after termination

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: "David G. Johnston" <david.g.johnston@gmail.com>
Cc: Magnus Hagander <magnus@hagander.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Fujii Masao <masao.fujii@oss.nttdata.com>
Date: 2020-10-22T04:12:33Z
Lists: pgsql-hackers 
On Thu, Oct 22, 2020 at 8:39 AM David G. Johnston
<david.g.johnston@gmail.com> wrote:
>
>> If the backend is terminated within the user specified timeout then
>> the function returns true, otherwise false.
>
> I’m suggesting an option for the second case to fail instead of returning false.
>

That seems fine.

>
>> >
>> > I could imagine, in theory at least, wanting to wait for a backend to go idle as well as for it disappearing.  Scope creep in terms of this patch's goal but worth at least considering now.
>> >
>>
>> IIUC, do we need a new option, something like pg_wait_backend(pid,
>> timeout, waituntil) where "waituntil" if specified "idle" waits until
>> the given backend goes to idle mode, or "termination" waits until
>> termination?
>>
>> If my understanding is wrong, could you please explain more?
>
>
> Yes, this describes what i was thinking.
>

+1.

I will implement these functionality and post a new patch soon.

With Regards,
Bharath Rupireddy.
EnterpriseDB: http://www.enterprisedb.com

Commits

  1. Copy-edit text for the pg_terminate_backend() "timeout" parameter.

  2. Remove pg_wait_for_backend_termination().

  3. Add functions to wait for backend termination

  4. Fix typo in comment.