Horton

Re: PG 15 (and to a smaller degree 14) regression due to ExprEvalStep size

Corey Huinker <corey.huinker@gmail.com>

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From: Corey Huinker <corey.huinker@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgresql.org, Nikita Glukhov <n.gluhov@postgrespro.ru>, Andrew Dunstan <andrew@dunslane.net>, David Rowley <dgrowleyml@gmail.com>
Date: 2023-02-23T18:39:14Z
Lists: pgsql-hackers 
On Wed, Feb 22, 2023 at 5:47 PM Andres Freund <andres@anarazel.de> wrote:

> Hi,
>
> On 2023-02-22 16:34:44 -0500, Tom Lane wrote:
> > I wrote:
> > > Andres Freund <andres@anarazel.de> writes:
> > >> Maybe it's worth sticking a StaticAssert() for the struct size
> > >> somewhere.
> >
> > > Indeed.  I thought we had one already.
> >
> > >> I'm a bit wary about that being too noisy, there are some machines
> with
> > >> odd alignment requirements. Perhaps worth restricting the assertion to
> > >> x86-64 + armv8 or such?
> >
> > > I'd put it in first and only reconsider if it shows unfixable problems.
> >
> > Now that we've got the sizeof(ExprEvalStep) under control, shouldn't
> > we do the attached?
>
> Indeed. Pushed.
>
> Let's hope there's no rarely used architecture with odd alignment rules.
>
> Greetings,
>
> Andres Freund
>
>
>
I have a question about this that may affect some of my future work.

My not-ready-for-16 work on CAST( ... ON DEFAULT ... ) involved making
FuncExpr/IoCoerceExpr/ArrayCoerceExpr have a safe_mode flag, and that
necessitates adding a reserror boolean to ExprEvalStep for subsequent steps
to test if the error happened.

Will that change be throwing some architectures over the 64 byte count?

Commits

  1. JSON_TABLE: Add support for NESTED paths and columns

  2. Add basic JSON_TABLE() functionality

  3. Add SQL/JSON query functions

  4. Add soft error handling to some expression nodes

  5. Adjust populate_record_field() to handle errors softly

  6. Refactor code used by jsonpath executor to fetch variables

  7. Add more SQL/JSON constructor functions

  8. SQL/JSON: support the IS JSON predicate

  9. SQL/JSON: add standard JSON constructor functions

  10. Add static assertion ensuring sizeof(ExprEvalStep) <= 64 bytes

  11. Remove size increase in ExprEvalStep caused by hashed saops

  12. pgstat: reduce timer overhead by leaving timer running.

  13. expression eval: Fix EEOP_JSON_CONSTRUCTOR and EEOP_JSONEXPR size.

  14. SQL/JSON query functions

  15. Speedup ScalarArrayOpExpr evaluation