Horton

Re: remaining sql/json patches

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: John Naylor <johncnaylorls@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, 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: 2023-11-29T00:32:07Z
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.

Andrew Dunstan <andrew@dunslane.net> writes:
> Cool, I took this and ran with it a bit. (See attached) Here are 
> comparative timings for 1000 iterations parsing most of the 
> information_schema.sql, all the way back to 9.3:
> ...
> ==== REL_15_STABLE ====
> Time: 3372.491 ms (00:03.372)
> ==== REL_16_STABLE ====
> Time: 1654.056 ms (00:01.654)
> ==== HEAD ====
> Time: 1614.949 ms (00:01.615)
> This is fairly repeatable.

These results astonished me, because I didn't recall us having done
anything that'd be likely to double the speed of the raw parser.
So I set out to replicate them, intending to bisect to find where
the change happened.  And ... I can't replicate them.  What I got
is essentially level performance from HEAD back to d10b19e22
(Stamp HEAD as 14devel):

HEAD: 3742.544 ms
d31d30973a (16 stamp): 3871.441 ms
596b5af1d (15 stamp): 3759.319 ms
d10b19e22 (14 stamp): 3730.834 ms

The run-to-run variation is a couple percent, which means that
these differences are down in the noise.  This is using your
test code from github (but with 5000 iterations not 1000).
Builds are pretty vanilla with asserts off, on an M1 MacBook Pro.
The bison version might matter here: it's 3.8.2 from MacPorts.

I wondered if you'd tested assert-enabled builds, but there
doesn't seem to be much variation with that turned on either.

So I'm now a bit baffled.  Can you provide more color on what
your test setup is?

			regards, tom lane