Horton

Re: remaining sql/json patches

jian he <jian.universality@gmail.com>

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From: jian he <jian.universality@gmail.com>
To: Amit Langote <amitlangote09@gmail.com>
Cc: Tomas Vondra <tomas.vondra@enterprisedb.com>, Himanshu Upadhyaya <upadhyaya.himanshu@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Erik Rijkers <er@xs4all.nl>, Andres Freund <andres@anarazel.de>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-03-26T10:16:00Z
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 Fri, Mar 22, 2024 at 12:08 AM Amit Langote <amitlangote09@gmail.com> wrote:
>
> On Wed, Mar 20, 2024 at 9:53 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > I'll push 0001 tomorrow.
>
> Pushed that one.  Here's the remaining JSON_TABLE() patch.
>

hi. minor issues i found json_table patch.

+ if (!IsA($5, A_Const) ||
+ castNode(A_Const, $5)->val.node.type != T_String)
+ ereport(ERROR,
+ errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("only string constants are supported in JSON_TABLE"
+   " path specification"),
+ parser_errposition(@5));
as mentioned in upthread, this error message should be one line.


+const TableFuncRoutine JsonbTableRoutine =
+{
+ JsonTableInitOpaque,
+ JsonTableSetDocument,
+ NULL,
+ NULL,
+ NULL,
+ JsonTableFetchRow,
+ JsonTableGetValue,
+ JsonTableDestroyOpaque
+};
should be:

const TableFuncRoutine JsonbTableRoutine =
{
.InitOpaque = JsonTableInitOpaque,
.SetDocument = JsonTableSetDocument,
.SetNamespace = NULL,
.SetRowFilter = NULL,
.SetColumnFilter = NULL,
.FetchRow = JsonTableFetchRow,
.GetValue = JsonTableGetValue,
.DestroyOpaque = JsonTableDestroyOpaque
};

+/*
+ * JsonTablePathSpec
+ * untransformed specification of JSON path expression with an optional
+ * name
+ */
+typedef struct JsonTablePathSpec
+{
+ NodeTag type;
+
+ Node   *string;
+ char   *name;
+ int name_location;
+ int location; /* location of 'string' */
+} JsonTablePathSpec;
the comment still does not explain the distinction between "location"
and "name_location"?


JsonTablePathSpec needs to be added to typedefs.list.
JsonPathSpec should be removed from typedefs.list.


+/*
+ * JsonTablePlanType -
+ * flags for JSON_TABLE plan node types representation
+ */
+typedef enum JsonTablePlanType
+{
+ JSTP_DEFAULT,
+ JSTP_SIMPLE,
+ JSTP_JOINED,
+} JsonTablePlanType;
+
+/*
+ * JsonTablePlanJoinType -
+ * JSON_TABLE join types for JSTP_JOINED plans
+ */
+typedef enum JsonTablePlanJoinType
+{
+ JSTP_JOIN_INNER,
+ JSTP_JOIN_OUTER,
+ JSTP_JOIN_CROSS,
+ JSTP_JOIN_UNION,
+} JsonTablePlanJoinType;
I can guess the enum value meaning of JsonTablePlanJoinType,
but I can't guess the meaning of "JSTP_SIMPLE" or "JSTP_JOINED".
adding some comments in JsonTablePlanType would make it more clear.

I think I can understand JsonTableScanNextRow.
but i don't understand JsonTablePlanNextRow.
maybe we can add some comments on JsonTableJoinState.


+-- unspecified plan (outer, union)
+select
+ jt.*
+from
+ jsonb_table_test jtt,
+ json_table (
+ jtt.js,'strict $[*]' as p
+ columns (
+ n for ordinality,
+ a int path 'lax $.a' default -1 on empty,
+ nested path 'strict $.b[*]' as pb columns ( b int path '$' ),
+ nested path 'strict $.c[*]' as pc columns ( c int path '$' )
+ )
+ ) jt;
+ n | a  | b | c
+---+----+---+----
+ 1 |  1 |   |
+ 2 |  2 | 1 |
+ 2 |  2 | 2 |
+ 2 |  2 | 3 |
+ 2 |  2 |   | 10
+ 2 |  2 |   |
+ 2 |  2 |   | 20
+ 3 |  3 | 1 |
+ 3 |  3 | 2 |
+ 4 | -1 | 1 |
+ 4 | -1 | 2 |
+(11 rows)
+
+-- default plan (outer, union)
+select
+ jt.*
+from
+ jsonb_table_test jtt,
+ json_table (
+ jtt.js,'strict $[*]' as p
+ columns (
+ n for ordinality,
+ a int path 'lax $.a' default -1 on empty,
+ nested path 'strict $.b[*]' as pb columns ( b int path '$' ),
+ nested path 'strict $.c[*]' as pc columns ( c int path '$' )
+ )
+ plan default (outer, union)
+ ) jt;
+ n | a  | b | c
+---+----+---+----
+ 1 |  1 |   |
+ 2 |  2 | 1 | 10
+ 2 |  2 | 1 |
+ 2 |  2 | 1 | 20
+ 2 |  2 | 2 | 10
+ 2 |  2 | 2 |
+ 2 |  2 | 2 | 20
+ 2 |  2 | 3 | 10
+ 2 |  2 | 3 |
+ 2 |  2 | 3 | 20
+ 3 |  3 |   |
+ 4 | -1 |   |
+(12 rows)
these two query results should be the same, if i understand it correctly.