Horton

Re: plan cache overhead on plpgsql expression

Amit Langote <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Pavel Stehule <pavel.stehule@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2020-03-19T09:47:17Z
Lists: pgsql-hackers 
Hi Pavel,

Sorry it took me a while to look at this.

On Tue, Feb 25, 2020 at 4:28 AM Pavel Stehule <pavel.stehule@gmail.com> wrote:
> po 24. 2. 2020 v 18:56 odesílatel Pavel Stehule <pavel.stehule@gmail.com> napsal:
>> 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.
>
> I am not sure, but after patching the SPI_prepare_params the current memory context is some short memory context.
>
> Can SPI_prepare_params change current memory context? It did before. But after patching different memory context is active.

I haven't been able to see the behavior you reported.  Could you let
me know what unexpected memory context you see in the problematic
case?

--
Thank you,
Amit

Commits

  1. Rearrange validity checks for plpgsql "simple" expressions.

  2. Improve performance of "simple expressions" in PL/pgSQL.

  3. Ensure that plpgsql cleans up cleanly during parallel-worker exit.