Horton

Re: remaining sql/json patches

amit <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: "Anton A. Melnikov" <a.melnikov@postgrespro.ru>
Cc: jian he <jian.universality@gmail.com>, Nikita Malakhov <hukutoc@gmail.com>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew@dunslane.net>, Erik Rijkers <er@xs4all.nl>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-10-17T04:02:45Z
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 10:44 PM Anton A. Melnikov
<a.melnikov@postgrespro.ru> wrote:
> On 16.10.2023 15:49, jian he wrote:
> > add the following code after ExecEvalJsonExprCoercion if
> > (!InputFunctionCallSafe(...) works, but seems like a hack.
> >
> > if (!val_string)
> > {
> > *op->resnull = true;
> > *op->resvalue = (Datum) 0;
> > }
>
> It seems the constraint should work here:
>
> After
>
> CREATE TABLE test (
>         js text,
>         i int,
>         x jsonb DEFAULT JSON_QUERY(jsonb '[1,2]', '$[*]' WITH WRAPPER)
>         CONSTRAINT test_constraint
>                 CHECK (JSON_QUERY(js::jsonb, '$.a' RETURNING char(5) OMIT QUOTES EMPTY ARRAY ON EMPTY) > 'a')
> );
>
> INSERT INTO test_jsonb_constraints VALUES ('[]');
>
> one expected to see an error like that:
>
> ERROR:  new row for relation "test" violates check constraint "test_constraint"
> DETAIL:  Failing row contains ([], null, [1, 2]).
>
> not "INSERT 0 1"

Yes, the correct thing here is for the constraint to fail.

One thing jian he missed during the debugging is that
ExecEvalJsonExprCoersion() receives the EMPTY ARRAY value via
*op->resvalue/resnull, set by ExecEvalJsonExprBehavior(), because
that's the ON EMPTY behavior specified in the constraint.  The bug was
that the code in ExecEvalJsonExprCoercion() failed to set val_string
to that value ("[]") before passing to InputFunctionCallSafe(), so the
latter would assume the input is NULL.

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