Start Debezium tutorial and execute a comaand like

curl -i -X POST -H "Accept:appContent-Type:application/json" http://localhost:8083/connectors/ -d @register-mysql.json; sleep 2; curl -i -X POST -H "Accept:application/json" -H  "Content-Type:application/json" http://localhost:83/connectors/ -d @register-mysql2.json

where register-mysql2.json is a request that registers second inctance of MySQL connector - with unique name and parameters.

In most cases the Connect will consume significant CPU resources.
When a thread dump is analyzed there are at least 3 or 4 threads that executes ChainedReader albeit there should be only 2.

The log file demonstartes that there is unrestriced polling by a reader instance.