Re: Can a long running procedure detect when smart shutdown is pending?

so 6. 7. 2024 v 8:19 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
napsal:

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> so 6. 7. 2024 v 8:06 odesílatel Achilleas Mantzios <
> a(dot)mantzios(at)cloud(dot)gatewaynet(dot)com> napsal:
>
>> Στις 6/7/24 08:39, ο/η Pavel Stehule έγραψε:
>>
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>> so 6. 7. 2024 v 1:36 odesílatel Dennis White <dwhite(at)seawardmoon(dot)com>
>> napsal:
>>
>>> Thanks for responding.
>>> This will be a stored procedure written in plpgsql that's kicked off by
>>> pg_cron.
>>> I wasn't sure a normal smart shutdown would stop it.
>>>
>>
>> shutdown try to cancel any query. The plpgsql routine should be canceled
>> without problems.
>>
>> fast mode will have this effect. smart mode not, from my testing. The
>> running queries do not get interrupted in smart shutdown.
>>
>
> ok
>
> but you can set timeout there. It doesn't help?
>
> You can create some aux postgresql connection with specific app name, and
> then you can monitor if this process still live from pg_stat_activity
>
> one process
>
> connect
> set application_name to 'xxxx';
>
> second process
> if not exists(select * from pg_stat_activity where appname = 'xxxx') then
> exit
> end if;
>
>
sorry - it cannot to help too

probably only one solution can be to write some extension and read some
internal state

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>
>>
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>>>
>>> Thanks
>>>
>>> On Fri, Jul 5, 2024 at 4:57 PM Achilleas Mantzios <
>>> a(dot)mantzios(at)cloud(dot)gatewaynet(dot)com> wrote:
>>>
>>>> Στις 5/7/24 21:12, ο/η Dennis White έγραψε:
>>>>
>>>> My project's DB has a mutli-step stored procedure using Transaction
>>>> Control that may take 30 minutes or more to complete.
>>>> I am curious if there is a way to make it more smart shutdown friendly
>>>> so it can stop between steps?
>>>>
>>>> We are using both PG 14 and PG 16 on Rhel 8.
>>>> Pardon me if it's obvious but is there a function to call or a table
>>>> that could be checked after a commit within the procedure to determine a
>>>> shutdown is pending?
>>>>
>>>> Maybe somehow checking the log for a message like :
>>>>
>>>> received smart shutdown request
>>>>
>>>> Or use tail_n_mail against the log and then implement some logic using
>>>> NOTIFY , ideally you want your procedure to be interrupted rather than do
>>>> polling.
>>>>
>>>>
>>>> Thanks,
>>>> Dennis
>>>>
>>>> --
>>>> Achilleas Mantzios
>>>> IT DEV - HEAD
>>>> IT DEPT
>>>> Dynacom Tankers Mgmt (as agents only)
>>>>
>>>> --
>> Achilleas Mantzios
>> IT DEV - HEAD
>> IT DEPT
>> Dynacom Tankers Mgmt (as agents only)
>>
>>