Merge and update on a table with a composite primary key extremely slow.

[malik-khalil]

Merge and update on a table with a composite primary key extremely slow.

After upgrading to the latest version, 2.3.232 merge and update statements became up to 25 times slower on a table with a composite primary key.
Had to replace the composite key with an ID (IDENTITY) column as primary key to reduce the execution time for merge and only use one WHERE condition on ID for update.

[grandinj]

do you have a self-contained test case?