[POC] Prototyping - MySQL User Defined Types

[marcalff]

Proof Of Concepts - MySQL User Defined Types

Contributes to #674

Caution

Proof of concepts code, do not merge, do not use in production.

This code is dirty and to throw away.
The point of this PR is to do prototyping, to identify what needs to be changed in the server, to start a technical discussion.

Quick start

Build

Compile with -DWITH_EXPERIMENTAL_UDT=ON -DWITH_DEBUG=ON in CMake.

Run

mtr --suite=udt

Current progress

Declare a UDT and provide an implementation:

CREATE TYPE test.complex_number AS BINARY(16);

INSTALL COMPONENT "file://component_udt_example";

Declare a UDT variable, perform operations provided by the component:

delimiter $$

CREATE PROCEDURE test.complex()
BEGIN
  DECLARE a test.complex_number;
  DECLARE b test.complex_number;
  DECLARE c test.complex_number;
  SET a = complex_number_from_string("1+2i");
  SET b = complex_number_from_string("3+4i");
  SET c = complex_number_add(a, b);
  # SELECT complex_number_to_string(c);
END$$

delimiter ;

Invoke the UDT implementation at runtime:

call test.complex();

Cleanup:

UNINSTALL COMPONENT "file://component_udt_example";

DROP PROCEDURE test.complex;

Component implementation

Check files under components/udt_example.

[marcalff]

Blocked by:

• Update PR workflows for actions/checkout v7 compatibility #715