[jira] [Commented] (KAFKA-6302) Topic can not be recreated after it is deleted

["Waleed Fateem (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-6302?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16276063#comment-16276063 ] 

Waleed Fateem commented on KAFKA-6302:
--------------------------------------

Hi kic,

I think you should be able to recreate a topic with the same name without any issues, but this is with the assumption that the topic doesn't already exist. Did you make sure that the topic was deleted properly?

Did you run the kafkak-topics --zookeeper ZHOST:2181 --describe command after deletion to confirm that your topic was in fact deleted and not in the "marked for deletion" state?

What error, if any, did you see when you attempted to create the topic again?

I don't believe the topic will be deleted so long as you have clients connected to the topic. I think at that point Kafka is just going to mark the topic for deletion. I would need to run a test to confirm. 

> Topic can not be recreated after it is deleted
> ----------------------------------------------
>
>                 Key: KAFKA-6302
>                 URL: https://issues.apache.org/jira/browse/KAFKA-6302
>             Project: Kafka
>          Issue Type: Bug
>          Components: admin, clients
>    Affects Versions: 1.0.0
>            Reporter: kic
>
> I use an embedded kafka for unit test. My application relies on the ability to recreate topics programmatically. Currently it is not possible to re-create a topic after it has been deleted.
> {code}
> // needs compile time depedency 'net.manub:scalatest-embedded-kafka_2.11:1.0.0' and 'org.apache.kafka:kafka-clients:1.0.0'
> package kic.kafka.embedded
> import java.util.Properties
> import org.apache.kafka.clients.admin.{AdminClient, NewTopic}
> import org.scalatest._
> import scala.collection.JavaConverters._
> class EmbeddedKafaJavaWrapperTest extends FlatSpec with Matchers {
>   val props = new Properties()
>   val testTopic = "test-topic"
>   "The admin client" should "be able to create, delete and re-create topics" in {
>     props.setProperty("bootstrap.servers", "localhost:10001")
>     props.setProperty("delete.enable.topic", "true")
>     props.setProperty("group.id", "test-client")
>     props.setProperty("key.deserializer", "org.apache.kafka.common.serialization.LongDeserializer")
>     props.setProperty("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
>     props.setProperty("clinet.id", "test-client")
>     props.setProperty("key.serializer", "org.apache.kafka.common.serialization.LongSerializer")
>     props.setProperty("value.serializer", "org.apache.kafka.common.serialization.StringSerializer")
>     EmbeddedKafaJavaWrapper.start(10001, 10002, props)
>     try {
>       implicit val admin = AdminClient.create(props)
>       // create topic and confirm it exists
>       createTopic(testTopic)
>       val topics = listTopics()
>       info(s"topics: $topics")
>       topics should contain(testTopic)
>       // now we should be able to send something to this topic
>       // TODO create producer and send something
>       // delete topic
>       deleteTopic(testTopic)
>       listTopics() shouldNot contain(testTopic)
>       // recreate topic
>       createTopic(testTopic)
>       // listTopics() should contain(testTopic)
>       // and finally consume from the topic and expect to get 0 entries
>       // TODO create consumer and poll once
>     } finally {
>       EmbeddedKafaJavaWrapper.stop()
>     }
>   }
>   def listTopics()(implicit admin: AdminClient) =
>     admin.listTopics().names().get()
>   def createTopic(topic: String)(implicit admin: AdminClient) =
>     admin.createTopics(Seq(new NewTopic(topic, 1, 1)).asJava)
>   def deleteTopic(topic: String)(implicit admin: AdminClient) =
>     admin.deleteTopics(Seq("test-topic").asJava).all().get()
> }
> {code}
> Btw, what happens to connected producers/consumers when I delete a topic? 



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