[KAFKA-7745] Kafka Connect doesn't create tombstone record for tasks of deleted connector

• Type: Bug
• Status: Open
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 1.1.1
• Component/s: connect
• Labels: needs-kip
• Assignee: Unassigned
• Reporter: Andrey Pustovetov
• Created: 17/Dec/18 14:51
• Updated: 22/Jul/19 15:27

Description

Test case

1. Create a connector:

   curl -i -XPOST -H "Accept:application/json" -H  "Content-Type:application/json" http://localhost:8083/connectors/ -d'
   {
     "name": "postgres-connector",
     "config": {
       "connector.class": "io.debezium.connector.postgresql.PostgresConnector",
       "database.hostname": "postgresql",
       "database.port": "5432",
       "database.user": "postgres",
       "database.password": "postgres",
       "database.dbname": "postgres",
       "database.server.name": "test",
       "slot.drop_on_stop": "true"
     }
   }'
   

2. Delete the connector:

   curl -XDELETE http://localhost:8083/connectors/postgres-connector
   

3. Check your config topic of Kafka Connect:

   ./bin/kafka-console-consumer.sh --bootstrap-server kafka:9092 --topic my-connect-config --from-beginning --property print.key=true
   

AR:
The following records are read from the config topic after the connector is created:

Key	Value
connector-postgres-connector	{"properties":{"connector.class":"io.debezium.connector.postgresql.PostgresConnector","database.hostname":"postgresql","database.port":"5432","database.user":"postgres","database.password":"postgres","database.dbname":"postgres","database.server.name":"test","slot.drop_on_stop":"true","name":"postgres-connector"}}
task-postgres-connector-0	{"properties":{"connector.class":"io.debezium.connector.postgresql.PostgresConnector","slot.drop_on_stop":"true","database.user":"postgres","database.dbname":"postgres","task.class":"io.debezium.connector.postgresql.PostgresConnectorTask","database.hostname":"postgresql","database.password":"postgres","name":"postgres-connector","database.server.name":"test","database.port":"5432"}}
commit-postgres-connector	{"tasks":1}

The following records are read from the config topic after the connector is deleted:

Key	Value
connector-postgres-connector	null
target-state-postgres-connector	null

Note that the tombstone record is missing for the task-postgres-connector-0 key.

Additionally, the following fields of org.apache.kafka.connect.storage.KafkaConfigBackingStore class are never cleared during connector removal:

• connectorTaskCounts
• taskConfigs
• deferredTaskUpdates

and can lead to memory leaks.