markus makela would you prefer this to be in the form of a UDF?

We just need access to it via the SQL interface. Anything else works for us but to keep it consistent, it could be a function.

I'll define the preliminary function name as mcsSystemPrimary and work based on the assumption that this function returns 1 if the system is the primary UM and 0 if it's not.

I will create the function as Markus describes.

To test, on any multi-UM system run:
UM1:
MariaDB [(none)]> select mcsSystemPrimary();
--------------------

--------------------

--------------------
1 row in set (0.005 sec)
UM2...N
MariaDB [(none)]> select mcsSystemPrimary();
--------------------

--------------------

--------------------
1 row in set (0.004 sec)

Re-assigned to me to review since Ben is away

Where are the tests for columnstore located?

Manually tested and the function seems to work. It returns 1 on the primary UM and 0 on secondary.

Added a simple test case and assigned it for review.