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: 2024-03-29T03:20:00Z
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.

Attachments

On Thu, Mar 28, 2024 at 1:23 PM Amit Langote <amitlangote09@gmail.com> wrote:
>
> On Wed, Mar 27, 2024 at 1:34 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > On Wed, Mar 27, 2024 at 12:42 PM jian he <jian.universality@gmail.com> wrote:
> > > hi.
> > > I don't fully understand all the code in json_table patch.
> > > maybe we can split it into several patches,
> >
> > I'm working on exactly that atm.
> >
> > > like:
> > > * no nested json_table_column.
> > > * nested json_table_column, with PLAN DEFAULT
> > > * nested json_table_column, with PLAN ( json_table_plan )
> >
> > Yes, I think it will end up something like this.  I'll try to post the
> > breakdown tomorrow.
>
> Here's patch 1 for the time being that implements barebones
> JSON_TABLE(), that is, without NESTED paths/columns and PLAN clause.
> I've tried to shape the interfaces so that those features can be added
> in future commits without significant rewrite of the code that
> implements barebones JSON_TABLE() functionality.  I'll know whether
> that's really the case when I rebase the full patch over it.
>
> I'm still reading and polishing it and would be happy to get feedback
> and testing.
>

+static void
+JsonValueListClear(JsonValueList *jvl)
+{
+ jvl->singleton = NULL;
+ jvl->list = NULL;
+}
 jvl->list is a List structure, do we need to set it like "jvl->list = NIL"?

+ if (jperIsError(res))
+ {
+ /* EMPTY ON ERROR case */
+ Assert(!planstate->plan->errorOnError);
+ JsonValueListClear(&planstate->found);
+ }
i am not sure the comment is right.
`SELECT * FROM JSON_TABLE(jsonb'"1.23"', 'strict $.a' COLUMNS (js2 int
PATH '$') );`
will execute jperIsError branch.
also
SELECT * FROM JSON_TABLE(jsonb'"1.23"', 'strict $.a' COLUMNS (js2 int
PATH '$') default '1' on error);

I think it means applying path_expression, if the top level on_error
behavior is not on error
then ` if (jperIsError(res))` part may be executed.



--- a/src/include/utils/jsonpath.h
+++ b/src/include/utils/jsonpath.h
@@ -15,6 +15,7 @@
 #define JSONPATH_H

 #include "fmgr.h"
+#include "executor/tablefunc.h"
 #include "nodes/pg_list.h"
 #include "nodes/primnodes.h"
 #include "utils/jsonb.h"

should be:
+#include "executor/tablefunc.h"
 #include "fmgr.h"


+<synopsis>
+JSON_TABLE (
+    <replaceable>context_item</replaceable>,
<replaceable>path_expression</replaceable> <optional> AS
<replaceable>json_path_name</replaceable> </optional> <optional>
PASSING { <replaceable>value</replaceable> AS
<replaceable>varname</replaceable> } <optional>, ...</optional>
</optional>
+    COLUMNS ( <replaceable
class="parameter">json_table_column</replaceable> <optional>,
...</optional> )
+    <optional> { <literal>ERROR</literal> | <literal>EMPTY</literal>
} <literal>ON ERROR</literal> </optional>
+)
top level (not in the COLUMN clause) also allows
<literal>NULL</literal> <literal>ON ERROR</literal>.

SELECT JSON_VALUE(jsonb'"1.23"', 'strict $.a' null on error);
returns one value.
SELECT * FROM JSON_TABLE(jsonb'"1.23"', 'strict $.a' COLUMNS (js2 int
PATH '$') NULL on ERROR);
return zero rows.
Is this what we expected?


main changes are in jsonpath_exec.c, parse_expr.c, parse_jsontable.c
overall the coverage seems pretty good.
I added some tests to improve the coverage.