Horton

Re: remaining sql/json patches

amit <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Nikita Malakhov <hukutoc@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew@dunslane.net>, jian he <jian.universality@gmail.com>, Erik Rijkers <er@xs4all.nl>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-10-17T11:12:22Z
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, Oct 16, 2023 at 5:21 PM Nikita Malakhov <hukutoc@gmail.com> wrote:
>
> Hi!
>
> With the latest set of patches we encountered failure with the following query:
>
> postgres@postgres=# SELECT JSON_QUERY(jsonpath '"aaa"', '$' RETURNING text);
> server closed the connection unexpectedly
>         This probably means the server terminated abnormally
>         before or while processing the request.
> The connection to the server was lost. Attempting reset: Failed.
> The connection to the server was lost. Attempting reset: Failed.
> Time: 11.165 ms
>
> A colleague of mine, Anton Melnikov, proposed the following changes which slightly
> alter coercion functions to process this kind of error correctly.
>
> Please check attached patch set.

Thanks for the patches.

I think I understand patch 1. It makes each of JSON_{QUERY | VALUE |
EXISTS}() use FORMAT JSON for the context item by default, which I
think is the correct behavior.

As for patch 2, maybe the executor part is fine, but I'm not so sure
about the parser part.  Could you please explain why you think the
parser must check error-safety of the target type for allowing IO
coercion for non-ERROR behaviors?

Even if we consider that that's what should be done, it doesn't seem
like a good idea for the parser to implement its own logic for
determining error-safety.  IOW, the parser should really be using some
type cache API.  I thought there might have been a flag in pg_proc
(prosafe) or pg_type (typinsafe), but apparently there isn't.

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