Re: plan cache overhead on plpgsql expression

po 24. 2. 2020 v 18:47 odesílatel Pavel Stehule <pavel.stehule@gmail.com> napsal:

čt 20. 2. 2020 v 20:15 odesílatel Pavel Stehule <pavel.stehule@gmail.com> napsal:

st 19. 2. 2020 v 8:09 odesílatel Amit Langote <amitlangote09@gmail.com> napsal:

On Wed, Feb 19, 2020 at 3:56 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Wed, Feb 19, 2020 at 3:38 PM Pavel Stehule <pavel.stehule@gmail.com> wrote:
> > st 19. 2. 2020 v 7:30 odesílatel Pavel Stehule <pavel.stehule@gmail.com> napsal:
> >> út 18. 2. 2020 v 17:08 odesílatel Amit Langote <amitlangote09@gmail.com> napsal:
> >>> > I updated the patch to do that.
> >>> >
> >>> > With the new patch, `select foo()`, with inline-able sql_incr() in it,
> >>> > runs in 679 ms.
> >>> >
> >>> > Without any inline-able function, it runs in 330 ms, whereas with
> >>> > HEAD, it takes 590 ms.
> >>>
> >>> I polished it a bit.
> >>
> >>
> >> the performance looks very interesting - on my comp the execution time of  100000000 iterations was decreased from 34 sec to 15 sec,
> >>
> >> So it is interesting speedup
> >
> > but regress tests fails
>
> Oops, I failed to check src/pl/plpgsql tests.
>
> Fixed in the attached.

Added a regression test based on examples discussed here too.

It is working without problems

I think this patch is very interesting for Postgres 13

I checked a performance of this patch again and I think so there is not too much space for another optimization - maybe JIT can help.

There is relative high overhead of call of strict functions - the params are repeatedly tested against NULL.

But I found one issue - I don't know if this issue is related to your patch or plpgsql_check.

plpgsql_check try to clean after it was executed - it cleans all plans. But some pointers on simple expressions are broken after catched exceptions.

expr->plan = 0x80. Is interesting, so other fields of this expressions are correct.

Regards

Pavel

Regards

Pavel

Thanks,
Amit