Horton

Re: remaining sql/json patches

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Amit Langote <amitlangote09@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew@dunslane.net>, Erik Rijkers <er@xs4all.nl>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2023-11-23T10:46:51Z
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.

+/*
+ * Evaluate or return the step address to evaluate a coercion of a JSON item
+ * to the target type.  The former if the coercion must be done right away by
+ * calling the target type's input function, and for some types, by calling
+ * json_populate_type().
+ *
+ * Returns the step address to be performed next.
+ */
+void
+ExecEvalJsonCoercionViaPopulateOrIO(ExprState *state, ExprEvalStep *op,
+ ExprContext *econtext)

the comment seems not right? it does return anything. it did the evaluation.

some logic in ExecEvalJsonCoercionViaPopulateOrIO, like if
(SOFT_ERROR_OCCURRED(escontext_p)) and if
(!InputFunctionCallSafe){...}, seems validated twice,
ExecEvalJsonCoercionFinish also did it. I uncommented the following
part, and still passed the test.
/src/backend/executor/execExprInterp.c
4452: // if (SOFT_ERROR_OCCURRED(escontext_p))
4453: // {
4454: // post_eval->error.value = BoolGetDatum(true);
4455: // *op->resvalue = (Datum) 0;
4456: // *op->resnull = true;
4457: // }

4470: // post_eval->error.value = BoolGetDatum(true);
4471: // *op->resnull = true;
4472: // *op->resvalue = (Datum) 0;
4473: return;

Correct me if I'm wrong.
like in "empty array on empty empty object on error", the "empty
array" refers to constant literal '[]' the assumed data type is jsonb,
the "empty object" refers to const literal '{}', the assumed data type
is jsonb.

--these two queries will fail very early, before ExecEvalJsonExprPath.
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.a' RETURNING int4range
default '[1.1,2]' on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.a' RETURNING int4range
default '[1.1,2]' on empty);

-----these four will fail later, and will call
ExecEvalJsonCoercionViaPopulateOrIO twice.
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
object on empty empty object on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
array on empty empty array on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
array on empty empty object on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
object on empty empty array on error);

-----however these four will not fail.
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
object on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
array on error);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
array on empty);
SELECT JSON_QUERY(jsonb '{"a":[3,4]}', '$.z' RETURNING int4range empty
object on empty);

should the last four query fail or just return null?