MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
Given a connection ID, enables Performance Schema instrumentation for the thread. Produces a result set indicating how many threads were enabled. Already enabled threads do not count.
                in_connection_id BIGINT: The
                connection ID. This is a value of the type given in the
                PROCESSLIST_ID column of the
                Performance Schema threads
                table or the Id column of
                SHOW PROCESSLIST output.
              
Enable a specific connection by its connection ID:
mysql> CALL sys.ps_setup_enable_thread(225);
+------------------+
| summary          |
+------------------+
| Enabled 1 thread |
+------------------+
Enable the current connection:
mysql> CALL sys.ps_setup_enable_thread(CONNECTION_ID());
+------------------+
| summary          |
+------------------+
| Enabled 1 thread |
+------------------+