Re: remaining sql/json patches

John Naylor <johncnaylorls@gmail.com>

From: John Naylor <johncnaylorls@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Andrew Dunstan <andrew@dunslane.net>, Amit Langote <amitlangote09@gmail.com>, Andres Freund <andres@anarazel.de>, jian he <jian.universality@gmail.com>, Erik Rijkers <er@xs4all.nl>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-01-22T06:19:17Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →
  1. SQL/JSON: Various improvements to SQL/JSON query function docs

  2. SQL/JSON: Fix some obsolete comments.

  3. SQL/JSON: Fix issues with DEFAULT .. ON ERROR / EMPTY

  4. JSON_TABLE: Add support for NESTED paths and columns

  5. Fix JsonExpr deparsing to emit QUOTES and WRAPPER correctly

  6. Fix typo introduced in 6185c9737

  7. Add basic JSON_TABLE() functionality

  8. Avoid splitting errmsg string to span multiple lines

  9. Add SQL/JSON query functions

  10. Implement various jsonpath methods

  11. Add soft error handling to some expression nodes

  12. Adjust populate_record_field() to handle errors softly

  13. Refactor code used by jsonpath executor to fetch variables

  14. Test EXPLAIN (FORMAT JSON) ... XMLTABLE

  15. Simplify productions for FORMAT JSON [ ENCODING name ]

  16. Add trailing commas to enum definitions

  17. doc: add missing <returnvalue> and whitespace

  18. Add more SQL/JSON constructor functions

  19. Rename a nonterminal used in SQL/JSON grammar

  20. Some refactoring to export json(b) conversion functions

  21. Don't include CaseTestExpr in JsonValueExpr.formatted_expr

  22. Code review for commit b6e1157e7d

  23. Pass constructName to transformJsonValueExpr()

  24. Unify JSON categorize type API and export for external use

  25. Make some indentation in gram.y consistent

  26. Allow most keywords to be used as column labels without requiring AS.

  27. Reduce size of backend scanner's tables.

  28. Use perfect hashing, instead of binary search, for keyword lookup.

On Mon, Nov 27, 2023 at 9:06 PM Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
> At this point one thing that IMO we cannot afford to do, is stop feature
> progress work on the name of parser speed.  I mean, parser speed is
> important, and we need to be mindful that what we add is reasonable.
> But at some point we'll probably have to fix that by parsing
> differently (a top-down parser, perhaps?  Split the parser in smaller
> pieces that each deal with subsets of the whole thing?)

I was reorganizing some old backups and rediscovered an experiment I
did four years ago when I had some extra time on my hands, to use a
lexer generator that emits a state machine driven by code, rather than
a table. It made parsing 12% faster on the above info-schema test, but
only (maybe) 3% on parsing pgbench-like queries. My quick hack ended
up a bit uglier and more verbose than Flex, but that could be
improved, and in fact small components could be shared across the
whole code base. I might work on it again; I might not.