The ssg.counters optimization which is being executed from JDBC query assertion does not optimize the counters table.
As of Gateway 11.1.1, the MySQL Connector/J version it contains has modified behaviour compared to previous version that was in Gateway 11.1.00 such that using non-SELECT SQL statements that produce result sets with Perform JDBC Query assertion now fails with the following error:
"Can not issue executeUpdate() or executeLargeUpdate() with statements that produce result sets"
API Gateway all supported versions.
If you are experiencing this exact scenario then please open a support issue for further assistance.