Re: calling procedures is slow and consumes extra much memory against calling function

po 11. 5. 2020 v 7:25 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
napsal:

> Hi
>
> ne 10. 5. 2020 v 22:20 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> napsal:
>
>> Hi
>>
>> I try to use procedures in Orafce package, and I did some easy
>> performance tests. I found some hard problems:
>>
>> 1. test case
>>
>> create or replace procedure p1(inout r int, inout v int) as $$
>> begin v := random() * r; end
>> $$ language plpgsql;
>>
>> This command requires
>>
>> do $$
>> declare r int default 100; x int;
>> begin
>> for i in 1..300000 loop
>> call p1(r, x);
>> end loop;
>> end;
>> $$;
>>
>> about 2.2GB RAM and 10 sec.
>>
>> When I rewrite same to functions then
>>
>> create or replace function p1func2(inout r int, inout v int) as $$
>> begin v := random() * r; end
>> $$ language plpgsql;
>>
>> do $$
>> declare r int default 100; x int; re record;
>> begin
>> for i in 1..300000 loop
>> re := p1func2(r, x);
>> end loop;
>> end;
>> $$;
>>
>> Then execution is about 1 sec, and memory requirements are +/- zero.
>>
>> Minimally it looks so CALL statements has a memory issue.
>>
>
> The problem is in plpgsql implementation of CALL statement
>
> In non atomic case - case of using procedures from DO block, the
> expression plan is not cached, and plan is generating any time. This is
> reason why it is slow.
>
> Unfortunately, generated plans are not released until SPI_finish. Attached
> patch fixed this issue.
>

But now, recursive calling doesn't work :-(. So this patch is not enough

> Regards
>
> Pavel
>
>
>> Regards
>>
>> Pavel
>>
>>