executor: fix json_objectagg() on varbinary type

[wzru]

What problem does this PR solve?

Issue Number: close #25053

Problem Summary:

drop table if exists tbl_0;
create table tbl_0 (col_2 int, col_3 varbinary(163));
insert into tbl_0 values (1,'o');
select json_objectagg( col_2, col_3 ) from tbl_0;

expected:

+--------------------------------+
| json_objectagg( col_2, col_3 ) |
+--------------------------------+
| {"1": "base64:type15:bw=="}    |
+--------------------------------+

obtained:

+--------------------------------+
| json_objectagg( col_2, col_3 ) |
+--------------------------------+
| {"1": "o"}                     |
+--------------------------------+

What is changed and how it works?

What's Changed:

func (e *jsonObjectAgg) UpdatePartialResult implementation

How it Works:

add special handling for varbinary

Check List

Tests

• Integration test

Side effects

• Performance regression: Consumes more CPU

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has not been approved.

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[wzru]

/run-check_dev_2

[guo-shaoge]

Looks like it's not only for json_objectagg(). json_object() also has same behavior.

mysql> select json_object( col_2, col_3 ) from tbl_0;
+-----------------------------+
| json_object( col_2, col_3 ) |
+-----------------------------+
| {"1": "base64:type15:bw=="} |
+-----------------------------+

We also need handle binary type.

mysql> select json_object( col_2, col_3 ) from tbl_0;
+------------------------------+
| json_object( col_2, col_3 )  |
+------------------------------+
| {"1": "base64:type254:bwA="} |
+------------------------------+

[ichn-hu]

@wzru could you look up in mysql's doc about what is type:15?