This was done to simplify copying of with_* flags
Other things:
- Changed Flags to C++ enums, which enables gdb to print
out bit values for the flags. This also enables compiler
errors if one tries to manipulate a non existing bit in
a variable.
- Added set_maybe_null() as a shortcut as setting the
MAYBE_NULL flags was used in a LOT of places.
- Renamed PARAM flag to SP_VAR to ensure it's not confused with persistent
statement parameters.
The reason for the change is that neither clang or gcc can do efficient
code when several bit fields are change at the same time or when copying
one or more bits between identical bit fields.
Updated bits explicitely with & and | is MUCH more efficient than what
current compilers can do.
Quick grouping is not supported for JSON_OBJECTAGG. The same for GROUP_CONCAT too
so make sure that Item::quick_group is set to FALSE. We need to make sure that in
the case of JSON_OBJECTAGG we don't create an index over grouping fields of
the temp table and update the result after each iteration.
Instead we should first sort the result in accordance to the
GROUP BY fields and then perform the grouping and
write the result to the temp table.
Item_func_json_extract did not implement val_decimal(),
so CAST(JSON_EXTRACT('{"x":true}', '$.x') AS DECIMAL) erroneously
returned 0 with a warning because of convertion from the string "true"
to decimal.
Implementing val_decimal(), so boolean values are correctly handled.
We have to include NULL in the result which the GOUP_CONCAT doesn't
always do. Also converting should be done into another String instance
as these can be same.
The JSON_ARRAYAGG function extends the GROUP_CONCAT function and provides
a method of aggregating JSON results. The current implementation supports
DISTINCT and LIMIT but not ORDER BY (Oracle supports GROUP BY).
Adding GROUP BY support is possible but it requires some extra work as the
grouping appears to be done inside a temporary table that complicates
matters.
Added test cases that covert aggregation of all JSON types and JSON
validation for the generated results.
TODO:
- Make get_thd_memroot() inline
- To do this, we need to reduce dependence of include files, especially
so that sql_class.h is not depending in item.h
- Implementing stricter data type control for Item_long_func descendants
- Cleanup: renaming Type_handler::can_return_str_ascii() to can_return_text()
(a better name).
JSON_EXTRACT behaves specifically in the comparison,
so we have to implement specific method for that in
Arg_comparator.
Conflicts:
sql/item_cmpfunc.cc
character (").
The my_wildcmp function doesn't expect the string parameter to
have escapements, only the template. So the string
should be unescaped if necessary.
