Re: SQLFunctionCache and generic plans
| От | Pavel Stehule |
|---|---|
| Тема | Re: SQLFunctionCache and generic plans |
| Дата | |
| Msg-id | CAFj8pRD2Fa84HoH_R_S5aKngyA6a+Au7U6NyidfBMrwEjFAc9g@mail.gmail.com обсуждение исходный текст |
| Ответ на | SQLFunctionCache and generic plans (Ronan Dunklau <ronan.dunklau@aiven.io>) |
| Ответы |
Re: SQLFunctionCache and generic plans
|
| Список | pgsql-hackers |
Hi
čt 30. 1. 2025 v 9:50 odesílatel Alexander Pyhalov <a.pyhalov@postgrespro.ru> napsal:
Alexander Pyhalov писал(а) 2025-01-29 17:35:
> Tom Lane писал(а) 2025-01-17 21:27:
>> Alexander Pyhalov <a.pyhalov@postgrespro.ru> writes:
>>> I've rebased patch on master. Tests pass here.
>>
>> The cfbot still doesn't like it; my guess is that you built without
>> --with-libxml and so didn't notice the effects on xml.out.
>
> Hi. Thank you for review.
>
> I've updated patch.
Sorry, missed one local patch to fix memory bloat during replaning. Also
fixed a compiler warning.
Did you do some performance checks?
I tried some worst case
CREATE OR REPLACE FUNCTION fx(int)
RETURNS int AS $$
SELECT $1 + $1
$$ LANGUAGE SQL IMMUTABLE;
CREATE OR REPLACE FUNCTION fx2(int)
RETURNS int AS $$
SELECT $1 * 2
$$ LANGUAGE SQL IMMUTABLE;
do $$
begin
for i in 1..1000000 loop
perform fx(i); -- or fx2
end loop;
end;
$$;
DO
begin
for i in 1..1000000 loop
perform fx(i); -- or fx2
end loop;
end;
$$;
DO
The patched version reduces the difference between execution fx and fx2, but patched version is about 10% slower than unpatched.
The overhead of plan cache looks significant for simple cases (and a lot of SQL functions are very simple).
Regards
Pavel
--
Best regards,
Alexander Pyhalov,
Postgres Professional
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