[KAFKA-15252] Task is not stopped until the poll interval passes in case of task restarting.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Duplicate
• Component/s: connect
• Assignee: Unassigned
• Reporter: Nikita
• Created: 26/Jul/23 06:43
• Updated: 31/Jul/23 12:17
• Resolved: 31/Jul/23 12:17

Description

We face a problem with restarting of the tasks, sometimes it leads to resource leak. 

We used the jdbc source connector and noticed an increasing of count of opened sessions on Vertica side. But this problem is applicable for all databases and possibly for all source connectors.

Our case is the next: 

1) Run jdbc source connector (io.confluent.connect.jdbc.JdbcSourceConnector) and set poll.interval.ms (86400000) > task.shutdown.graceful.timeout.ms (it's the property on Kafka-connect side, we set 10000)

2) Send POST /connectors/<connector_name>/tasks/<task_number>/restart

ER: count of session is the same as before restart

AR: count of session increases

The main problem is when org.apache.kafka.connect.runtime.Worker#stopAndAwaitTasks(java.util.Collection<org.apache.kafka.connect.util.ConnectorTaskId>)  method is called it doesn't stop a source task itself. 
The source task stops only if polling process stops on source task side. 

Issue Links

• duplicates: KAFKA-15090 Source tasks are no longer stopped on a separate thread
• duplicates: KAFKA-14725 Improve cancellation semantics for connector tasks