Horton

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

Amit Langote <amitlangote09@gmail.com>

View thread View on postgr.es
From: Amit Langote <amitlangote09@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: "Jonathan S. Katz" <jkatz@postgresql.org>, Andrew Dunstan <andrew@dunslane.net>, David Rowley <dgrowleyml@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Michael Paquier <michael@paquier.xyz>, John Naylor <john.naylor@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Peter Geoghegan <pg@bowt.ie>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Nikita Glukhov <n.gluhov@postgrespro.ru>
Date: 2022-08-10T13:27:08Z
Lists: pgsql-hackers 
On Wed, Aug 10, 2022 at 3:57 AM Andres Freund <andres@anarazel.de> wrote:
> One way this code could be drastically simplified is to force all
> type-coercions to go through the "io coercion" path, which could be
> implemented as a single execution step (which thus could trivially
> start/finish a subtransaction) and would remove a lot of the complicated code
> around coercions.

Could you please clarify how you think we might do the io coercion
wrapped with a subtransaction all as a single execution step?  I
would've thought that we couldn't do the sub-transaction without
leaving ExecInterpExpr() anyway, so maybe you meant the io coercion
itself was done using some code outside ExecInterpExpr()?

The current JsonExpr code does it by recursively calling
ExecInterpExpr() using the nested ExprState expressly for the
coercion.

-- 
Thanks, Amit Langote
EDB: http://www.enterprisedb.com

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