title: Kafka JDBC Sink Connector: no tasks assigned
body: <p>I try to start JDBC sink connector with following configuration:</p>
  
  <pre><code>{
      "name": "crm_data-sink_hh",
      "config": {
          "connector.class": "io.confluent.connect.jdbc.JdbcSinkConnector",
          "tasks.max": 6,
          "topics": "crm_account,crm_competitor,crm_event,crm_event_participation",
  
          "connection.url": "jdbc:postgresql://db_host/hh?prepareThreshold=0",
          "connection.user": "db_user",
          "connection.password": "${file:db_hh_kafka_connect_pass}",
          "dialect.name": "PostgreSqlDatabaseDialect",
  
          "insert.mode": "upsert",
          "pk.mode": "record_value",
          "pk.fields": "guid",
  
          "errors.tolerance": "all",
          "errors.log.enable":true,
          "errors.log.include.messages":true,
  
          "errors.deadletterqueue.topic.name":"crm_data_deadletterqueue",
          "errors.deadletterqueue.context.headers.enable":true
      }
  }
  </code></pre>
  
  <p>But no tasks are running while connector is in running state:</p>
  
  <pre><code>curl -X GET http://kafka-connect:10900/connectors/crm_data-sink_hh/status
  {"name":"crm_data-sink_hh","connector":{"state":"RUNNING","worker_id":"172.16.24.14:10900"},"tasks":[],"type":"sink"}
  </code></pre>
  
  <p>I faced this issue many times, but I'm very confused because it happens randomly. My question is very similar with <a href="https://stackoverflow.com/questions/43254567/kafka-sink-connector-no-tasks-assigned-even-after-restart">this</a> question. I would appreciate any help!</p>
  
  <hr>
  
  <p><em>Update. 11/04/2019</em> (unfortunately, now I have only INFO level log)</p>
  
  <p>Finally, after few attempts I started connector with running tasks by updating config of the existing connector <code>crm_data-sink_db_hh</code>:</p>
  
  <pre><code>$ curl -X GET http://docker61:10900/connectors/crm_data-sink_db_hh/status
  {"name":"crm_data-sink_db_hh","connector":{"state":"RUNNING","worker_id":"192.168.1.198:10900"},"tasks":[],"type":"sink"}
  
  $ curl -X GET http://docker61:10900/connectors/crm_data-sink_db_hh/status
  {"name":"crm_data-sink_db_hh","connector":{"state":"RUNNING","worker_id":"192.168.1.198:10900"},"tasks":[],"type":"sink"}
  
  $ curl -X PUT -d @new_config.json http://docker21:10900/connectors/crm_data-sink_db_hh/config -H 'Content-Type: application/json'
  
  $ curl -X GET http://docker61:10900/connectors/crm_data-sink_db_hh/status
  {"name":"crm_data-sink_db_hh","connector":{"state":"UNASSIGNED","worker_id":"192.168.1.198:10900"},"tasks":[],"type":"sink"}
  
  $ curl -X GET http://docker61:10900/connectors/crm_data-sink_db_hh/status
  {"name":"crm_data-sink_db_hh","connector":{"state":"RUNNING","worker_id":"172.16.36.11:10900"},"tasks":[{"state":"UNASSIGNED","id":0,"worker_id":"172.16.32.11:10900"},{"state":"UNASSIGNED","id":1,"worker_id":"172.16.32.11:10900"},{"state":"RUNNING","id":2,"worker_id":"192.168.2.243:10900"},{"state":"UNASSIGNED","id":3,"worker_id":"172.16.32.11:10900"},{"state":"UNASSIGNED","id":4,"worker_id":"172.16.32.11:10900"}],"type":"sink"}
  
  $ curl -X GET http://docker61:10900/connectors/crm_data-sink_db_hh/status
  {"name":"crm_data-sink_db_hh","connector":{"state":"RUNNING","worker_id":"192.168.1.198:10900"},"tasks":[{"state":"RUNNING","id":0,"worker_id":"192.168.1.198:10900"},{"state":"RUNNING","id":1,"worker_id":"192.168.1.198:10900"},{"state":"RUNNING","id":2,"worker_id":"192.168.1.198:10900"},{"state":"RUNNING","id":3,"worker_id":"192.168.1.198:10900"},{"state":"RUNNING","id":4,"worker_id":"192.168.1.198:10900"},{"state":"RUNNING","id":5,"worker_id":"192.168.1.198:10900"}],"type":"sink"}
  </code></pre>
  
  <p>Log:</p>
  
  <pre><code>[2019-04-11 16:02:15,167] INFO Connector crm_data-sink_db_hh config updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:15,668] INFO Rebalance started (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:15,668] INFO Stopping connector crm_data-source (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:15,668] INFO Stopping task crm_data-source-0 (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:15,668] INFO Stopping connector crm_data-sink_pandora (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:15,668] INFO Stopping JDBC source task (io.confluent.connect.jdbc.source.JdbcSourceTask)
  [2019-04-11 16:02:15,668] INFO Stopping table monitoring thread (io.confluent.connect.jdbc.JdbcSourceConnector)
  ...
  Stopping connectors and tasks 
  ...
  [2019-04-11 16:02:17,373] INFO 192.168.1.91 - - [11/Apr/2019:13:02:14 +0000] "POST /connectors HTTP/1.1" 201 768  2468 (org.apache.kafka.connect.runtime.rest.RestServer)
  [2019-04-11 16:02:20,668] ERROR Graceful stop of task crm_data-source-1 failed. (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:20,669] ERROR Graceful stop of task crm_data-source-0 failed. (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:20,669] ERROR Graceful stop of task crm_data-source-3 failed. (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:20,669] ERROR Graceful stop of task crm_data-source-2 failed. (org.apache.kafka.connect.runtime.Worker)
  [2019-04-11 16:02:20,669] INFO Finished stopping tasks in preparation for rebalance (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,669] INFO [Worker clientId=connect-1, groupId=21] (Re-)joining group (org.apache.kafka.clients.consumer.internals.AbstractCoordinator)
  [2019-04-11 16:02:20,681] INFO Tasks [crm_data-sink_hhru-0, crm_data-sink_hhru-3, crm_data-sink_hhru-4, crm_data-sink_hhru-1, crm_data-sink_hhru-2, crm_data-sink_hhru-5, crm_data-pandora_sink-0, crm_data-pandora_sink-2, crm_data-pandora_sink-1, crm_data-pandora_sink-4, crm_data-pandora_sink-3, crm_data-pandora_sink-03-0, crm_data-pandora_sink-03-2, crm_data-pandora_sink-03-1, crm_data-pandora_sink-00-1, crm_data-pandora_sink-00-0, crm_data-pandora_sink-00-3, crm_data-pandora_sink-00-2, crcrm_data-pandora_sink-00-4, crm_data-sink_hh-00-0, crm_data-sink_hh-00-1, crm_data-sink_hh-00-2, crm_data-pandora_sink-test-3, crm_data-pandora_sink-test-2, crm_data-pandora_sink-test-4,crm_data-pandora_sink-01-2, crm_data-pandora_sink-01-1, crm_data-pandora_sink-01-0, crm_data-source-3, crm_data-source-2, crm_data-source-1, crm_data-source-0, crm_data-sink_db_hh-0, crm_data-sink_db_hh-1, crm_data-sink_db_hh-2, crm_data-sink_hh-01-0, crm_data-sink_hh-01-1, crm_data-sink_hh-01-2, crm_data-sink_hh-01-3, crm_data-sink_hh-00-3, crm_data-sink_hh-00-4, crm_data-sink_hh-00-5, crm_data-sink_hh-1, crm_data-sink_hh-0, crm_data-sink_hh-3, crm_data-sink_hh-2, crm_data-sink_hh-5, crm_data-sink_hh-4, crm_data-sink_pandora-5, crm_data-sink_pandora-0, crm_data-sink_pandora-1, crm_data-sink_pandora-2, crm_data-sink_pandora-3, crm_data_account_on_competitors-source-0, crm_data-sink_pandora-4] configs updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,681] INFO Tasks [] configs updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,682] INFO Tasks [] configs updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,683] INFO Tasks [] configs updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,684] INFO Tasks [] configs updated (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO [Worker clientId=connect-1, groupId=21] Successfully joined group with generation 2206465 (org.apache.kafka.clients.consumer.internals.AbstractCoordinator)
  [2019-04-11 16:02:20,685] INFO Joined group and got assignment: Assignment{error=0, leader='connect-1-57140c1d-3b19-4fc0-b4ca-e6ce272e1924', leaderUrl='http://192.168.1.198:10900/', offset=1168, connectorIds=[crm_data-sink_db_hh, crm_data-source, crm_data-sink_pandora], taskIds=[crm_data-source-0, crm_data-source-1, crm_data-source-2, crm_data-source-3, crm_data-sink_pandora-0, crm_data-sink_pandora-1, crm_data-sink_pandora-2, crm_data-sink_pandora-3, crm_data-sink_pandora-4, crm_data-sink_pandora-5]} (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO Starting connectors and tasks using config offset 1168 (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO Starting connector crm_data-sink_db_hh (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO Starting connector crm_data-source (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO Starting connector crm_data-sink_pandora (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  [2019-04-11 16:02:20,685] INFO Starting task crm_data-source-0 (org.apache.kafka.connect.runtime.distributed.DistributedHerder)
  ...
  Starting connectors and tasks
  ...
  </code></pre>
  
  <hr>
  
  <p><em>Update. 12/04/2019</em></p>
  
  <p>I increased log level and reproduced the issue. I see a lot of records for different tasks (tasks of already deleted connectors or not yet running tasks) like this: </p>
  
  <pre><code> [2019-04-12 15:14:32,360] DEBUG Storing new config for task crm_data-sink_hh-3 this will wait for a commit message before the new config will take effect. New config: {...} (org.apache.kafka.connect.storage.KafkaConfigBackingStore)
  </code></pre>
  
  <hr>
  
  <p>There are tasks of deleted connectors in the task list - is it ok? The same situation in the internal topics of Kafka Connect.</p>
  
  <p><em>My main question</em>: why the connector did not fail if there are no tasks are running for any reason? Since the connector does not work actually in this situation.</p>