Horton

Re: remaining sql/json patches

amit <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Andres Freund <andres@anarazel.de>, Erik Rijkers <er@xs4all.nl>, jian he <jian.universality@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-01-25T09:09:42Z
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 Wed, Jan 24, 2024 at 10:11 PM Amit Langote <amitlangote09@gmail.com> wrote:
> On Tue, Jan 23, 2024 at 12:46 AM jian he <jian.universality@gmail.com> wrote:
> > On Mon, Jan 22, 2024 at 10:28 PM Amit Langote <amitlangote09@gmail.com> wrote:
> > >
> > > > based on v35.
> > > > Now I only applied from 0001 to 0007.
> > > > For {DEFAULT expression  ON EMPTY}  | {DEFAULT expression ON ERROR}
> > > > restrict DEFAULT expression be either Const node or FuncExpr node.
> > > > so these 3 SQL/JSON functions can be used in the btree expression index.
> > >
> > > I'm not really excited about adding these restrictions into the
> > > transformJsonFuncExpr() path.  Index or any other code that wants to
> > > put restrictions already have those in place, no need to add them
> > > here.  Moreover, by adding these restrictions, we might end up
> > > preventing users from doing useful things with this like specify
> > > column references.  If there are semantic issues with allowing that,
> > > we should discuss them.
> > >
> >
> > after applying v36.
> > The following index creation and query operation works. I am not 100%
> > sure about these cases.
> > just want confirmation, sorry for bothering you....
>
> No worries; I really appreciate your testing and suggestions.
>
> > drop table t;
> > create table t(a jsonb, b  int);
> > insert into t select '{"hello":11}',1;
> > insert into t select '{"hello":12}',2;
> > CREATE INDEX t_idx2 ON t (JSON_query(a, '$.hello1' RETURNING int
> > default b + random() on error));
> > CREATE INDEX t_idx3 ON t (JSON_query(a, '$.hello1' RETURNING int
> > default random()::int on error));
> > create or replace function ret_setint() returns setof integer as
> > $$
> > begin
> >     -- perform pg_sleep(0.1);
> >     return query execute 'select 1 union all select 1';
> > end;
> > $$
> > language plpgsql IMMUTABLE;
> > SELECT JSON_query(a, '$.hello1'  RETURNING int default ret_setint() on
> > error) from t;
> > SELECT JSON_query(a, '$.hello1'  RETURNING int default sum(b) over()
> > on error) from t;
> > SELECT JSON_query(a, '$.hello1'  RETURNING int default sum(b) on
> > error) from t group by a;
> >
> > but the following cases will fail related to index and default expression.
> > create table zz(a int, b int);
> > CREATE INDEX zz_idx1 ON zz ( (b + random()::int));
> > create table ssss(a int, b int default ret_setint());
> > create table ssss(a int, b int default sum(b) over());
>
> I think your suggestion to add restrictions on what is allowed for
> DEFAULT makes sense.  Also, immutability shouldn't be checked in
> transformJsonBehavior(), but in contain_mutable_functions() as done in
> the attached.  Added some tests too.
>
> I still need to take a look at your other report regarding typmod but
> I'm out of energy today.

The attached updated patch should address one of the concerns --
JSON_QUERY() should now work appropriately with RETURNING type with
typmod whether or  OMIT QUOTES is specified.

But I wasn't able to address the problems with RETURNING
record_type_with_typmod, that is, the following example you shared
upthread:

create domain char3_domain_not_null as char(3) NOT NULL;
create domain hello as text not null check (value = 'hello');
create domain int42 as int check (value = 42);
create type comp_domain_with_typmod AS (a char3_domain_not_null, b int42);
select json_value(jsonb'{"rec": "(abcd,42)"}', '$.rec' returning
comp_domain_with_typmod);
 json_value
------------

(1 row)

select json_value(jsonb'{"rec": "(abcd,42)"}', '$.rec' returning
comp_domain_with_typmod error on error);
ERROR:  value too long for type character(3)

select json_value(jsonb'{"rec": "abcd"}', '$.rec' returning
char3_domain_not_null error on error);
 json_value
------------
 abc
(1 row)

The problem with returning comp_domain_with_typmod from json_value()
seems to be that it's using a text-to-record CoerceViaIO expression
picked from JsonExpr.item_coercions, which behaves differently than
the expression tree that the following uses:

select ('abcd', 42)::comp_domain_with_typmod;
   row
----------
 (abc,42)
(1 row)

I don't see a good way to make RETURNING record_type_with_typmod to
work cleanly, so I am inclined to either simply disallow the feature
or live with the limitation.










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