Analysis:
While writing the view to .FRM file, we check the datatype of each column
and append the appropriate type to the string (which will be written to
the frm). This is where the conversion from JSON to longtext happens because
that is how it is stored internally.
Now, while SELECT, when the frm is read it has longtext instead of JSON
which also results in changing the handler type. Since the handler types
dont match, m_format_json becomes false for that specific column.
Now, when filling the values, since the format is not json, it does not
get added in the result. Hence the output is NULL.
Fix:
Before writing the view to the FRM file, check if the datatype for the
column is JSON (which means the m_format_json will be true). If it is JSON
append JSON.
JSON_TABLE is marked as a special "*any_db*" table. Because this special
marking is processed all the way though to get_column_grant where
its processed like its in database called "*any_db*". As this
doesn't exist, only those users with global privileges can create
views on a JSON_TABLE.
Under a Prepared Statement protocol a Create_tmp_table is
used for the JSON_TABLE, but it gets assigned an "" database
name.
We correct this to give it "*any_db*" like the SQL parser
indicating that no database is needed.
To commonly correct the fill_effective_table_privileges
by looking explictly for the "*any_db*", those tables that
have this as the database name get SELECT privileges.
While correcting the database for the JSON_TABLE, lets give
it a "json_table" name rather than "(temporary)" for
greater clarity in warning messages.
(Polished initial patch by Alexey Botchkov)
Make the code handle DEFAULT values of any datatype
- Make Json_table_column::On_response::m_default be Item*, not LEX_STRING.
- Change the parser to use string literal non-terminals for producing
the DEFAULT value
-- Also, stop updating json_table->m_text_literal_cs for the DEFAULT
value literals as it is not used.
- Fix view-protocol: long expressions in SELECT
list should have "expr AS column_name".
- Also, moved the test from subselect*test to
suite/json/t/json_table.test.
SELECT FROM JSON_TABLE
Analysis: When fix_fields_if_needed() is called, it doesnt check if operands
are valid because check_cols() is not called. So it doesn't error out and
eventually crashes.
Fix: Use fix_fields_if_needed_for_scalar() instead of
fix_fields_if_needed(). It filters the scalar and returns the error if
it occurs.
Analysis: When trying to find path and handling the match for path,
value at current index is not set to 0 for array_counters. This causes wrong
current step value which eventually causes wrong cur_step->type value.
Fix: Set the value at current index for array_counters to 0.
This patch also fixes:
MDEV-27690 Crash on `CHARACTER SET csname COLLATE DEFAULT` in column definition
MDEV-27853 Wrong data type on column `COLLATE DEFAULT` and table `COLLATE some_non_default_collation`
MDEV-28067 Multiple conflicting column COLLATE clauses are not rejected
MDEV-28118 Wrong collation of `CAST(.. AS CHAR COLLATE DEFAULT)`
MDEV-28119 Wrong column collation on MODIFY + CONVERT
MDEV-27036: repeated "table" key resolve for print_explain_json
MDEV-27036: duplicated keys in best_access_path
MDEV-27036: Explain_aggr_filesort::print_json_members: resolve duplicated "filesort" member in Json object
MDEV-27036: Explain_basic_join::
print_explain_json_interns fixed start_dups_weedout case for main.explain_json test
Address review input: switch Name_resolution_context::ignored_tables from
table_map to a list of TABLE_LIST objects. The rationale is that table
bits may be changed due to query rewrites, etc, which may potentially
require updating ignored_tables.
The query used a subquery of this form:
SELECT ...
WHERE
EXISTS( SELECT ...
FROM JSON_TABLE(outer_ref, ..) as JT
WHERE trivial_correlation_cond)
EXISTS-to-IN conversion code was unable to see that the subquery will
still be correlated after the trivial_correlation is removed, which
eventually caused a crash due to inability to construct a query plan.
Fixed by making Item_subselect::walk() also walk arguments of Table
Functions.
(Also fixes MDEV-25254).
Re-work Name Resolution for the argument of JSON_TABLE(json_doc, ....)
function. The json_doc argument can refer to other tables, but it can
only refer to the tables that precede[*] the JSON_TABLE(...) call.
[*] - For queries with RIGHT JOINs, the "preceding" is determined after
the query is normalized by converting RIGHT JOIN into left one.
The implementation is as follows:
- Table function arguments use their own Name_resolution_context.
- The Name_resolution_context now has a bitmap of tables that should be
ignored when searching for a field.
- get_disallowed_table_deps() walks the TABLE_LIST::nested_join tree
and computes a bitmap of tables that do not "precede" the given
JSON_TABLE(...) invocation (according the above definition of
"preceding").
