Re: RFC: Logging plan of the running query

On 2021/07/09 14:05, torikoshia wrote:
> On 2021-07-02 23:21, Bharath Rupireddy wrote:
>> On Tue, Jun 22, 2021 at 8:00 AM torikoshia <torikoshia(at)oss(dot)nttdata(dot)com> wrote:
>>> Updated the patch.
>>
>> Thanks for the patch. Here are some comments on the v4 patch:
>
> Thanks for your comments and suggestions!
> I agree with you and updated the patch.
>
> On Thu, Jul 1, 2021 at 3:34 PM Fujii Masao <masao(dot)fujii(at)oss(dot)nttdata(dot)com> wrote:
>
>>      DO $$
>>      BEGIN
>>      PERFORM pg_sleep(100);
>>      END$$;
>>
>> When I called pg_log_current_query_plan() to send the signal to
>> the backend executing the above query, I got the following log message.
>> I think that this is not expected message. I guess this issue happened
>> because the information about query text and plan is retrieved
>> from ActivePortal. If this understanding is right, ISTM that we should
>> implement new mechanism so that we can retrieve those information
>> even while nested query is being executed.
>
> I'm now working on this comment.

One idea is to define new global pointer, e.g., "QueryDesc *ActiveQueryDesc;".
This global pointer is set to queryDesc in ExecutorRun()
(also maybe ExecutorStart()). And this is reset to NULL in ExecutorEnd() and
when an error is thrown. Then ProcessLogCurrentPlanInterrupt() can
get the plan of the currently running query from that global pointer
instead of ActivePortal, and log it. Thought?

Regards,

--
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION