Re: RFC: Logging plan of the running query

On 2023-10-24 16:12, Étienne BERSAC wrote:
>> Hi,
>>
>> Yeah, and when we have a situation where we want to run
>> pg_log_query_plan(), we can run it in any environment as long as it
>> is bundled with the core.
>
> Is it possible to get the plan of a backend programmatically without
> access to the logs?
>
> Something like pg_get_query_plan(pid, format) which output would be the
> same as EXPLAIN.

Do you imagine a function like below?

=# select pg_get_query_plan(100, 'plain');
QUERY PLAN
-------------------------------------------------------------------
Limit (cost=0.00..0.04 rows=1 width=273)
-> Seq Scan on pg_class (cost=0.00..17.14 rows=414 width=273)

If so, we once tried to implement such function for getting memory
contexts.
However, this attempt didn't succeed because it could lead dead lock
situation[1].

I think the same problem can occur when implementing
pg_get_query_plan().

[1]
https://www.postgresql.org/message-id/9a50371e15e741e295accabc72a41df1%40oss.nttdata.com
>
> Regards,
> Étienne BERSAC
> Dalibo

--
Regards,

--
Atsushi Torikoshi
NTT DATA Group Corporation