Moving geometry types aggregation inside Type_collection_geometry
This change introduces a static method Type_aggregator::find_handler_in_array(),
which will later be reused by other data type plugins.
If we have a mixture of:
- a MariaDB standard (built-in permanent) data type, and
- a non-standard (optionally compiled or pluggable) data type,
then ask the type collection of the non-standard type to aggregate the mixture.
If the non-standard collection fails, then continue aggregation
with Type_handler_data.
1. Removed TIMESTAMP/TRANSACTION unit auto-detection in favor of default TIMESTAMP.
Reasons:
1.1. rare practical use and doubtful advantage of such auto-detection;
1.2. it conflicts with MDEV-16226 (TRX_ID-based versioned tables performance improvement).
Needless check_unit membership removed.
2. SQL: versioning type handling refactoring
Vers_type_handler hierarchy stores versioning properties of type.
virtual Type_handler::vers() accesses specialization of
Vers_type_handler for specific type.
virtual Vers_type_handler::kind() returns versioning kind
(timestamp/trx_id).
Removed Type_handler::Vers_history_point_check_unit() in favor of
Type_handler::vers().
Renames:
require_timestamp() -> require_timestamp_error()
require_trx_id() -> require_trx_id_error()
EDIT by Alexander Barkov (@abarkov):
check_sys_fields() moved to Vers_type_handler::check_sys_fields()
Hiding the definitions inside Type_handler_xxx::name().
This is needed to avoid exporting members with MYSQL_PLUGIN_IMPORT,
which would be needed to compile data type plugins on Windows.
Introducing methods instead:
const Name version_mysql56() const;
const Name version_mariadb53() const;
This is needed to avoid exporting members with MYSQL_PLUGIN_IMPORT,
which would be needed to compile data type plugins on Windows.
Fix the build on clang. GCC only checks that a member function with
the C++11 override keyword is actually overriding a virtual member
function in a base class. In clang, you will get a warning for
overridden member functions that lack the keyword, if any overridden
member function of the class is declared with the keyword.
