Re: Is it useful to record whether plans are generic or custom?

On 2021-02-04 11:19, Kyotaro Horiguchi wrote:
> At Thu, 04 Feb 2021 10:16:47 +0900, torikoshia
> <torikoshia(at)oss(dot)nttdata(dot)com> wrote in
>> Chengxi Sun, Yamada-san, Horiguchi-san,
>>
>> Thanks for all your comments.
>> Adding only the number of generic plan execution seems acceptable.
>>
>> On Mon, Jan 25, 2021 at 2:10 PM Kyotaro Horiguchi
>> <horikyota(dot)ntt(at)gmail(dot)com> wrote:
>> > Note that ActivePortal is the closest nested portal. So it gives the
>> > wrong result for nested portals.
>>
>> I may be wrong, but I thought it was ok since the closest nested
>> portal is the portal to be executed.
>
> After executing the inner-most portal, is_plan_type_generic has a
> value for the inner-most portal and it won't be changed ever after. At
> the ExecutorEnd of all the upper-portals see the value for the
> inner-most portal left behind is_plan_type_generic nevertheless the
> portals at every nest level are independent.
>
>> ActivePortal is used in ExecutorStart hook in the patch.
>> And as far as I read PortalStart(), ActivePortal is changed to the
>> portal to be executed before ExecutorStart().
>>
>> If possible, could you tell me the specific case which causes wrong
>> results?
>
> Running a plpgsql function that does PREPRE in a query that does
> PREPARE?

Thanks for your explanation!

I confirmed that it in fact happened.

To avoid it, attached patch preserves the is_plan_type_generic before
changing it and sets it back at the end of pgss_ExecutorEnd().

Any thoughts?

Regards,

--
Atsushi Torikoshi