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From "Guozhang Wang (JIRA)" <j...@apache.org>
Subject [jira] [Created] (KAFKA-1286) Retry Can Block
Date Sat, 01 Mar 2014 01:49:19 GMT
Guozhang Wang created KAFKA-1286:

             Summary: Retry Can Block 
                 Key: KAFKA-1286
                 URL: https://issues.apache.org/jira/browse/KAFKA-1286
             Project: Kafka
          Issue Type: Sub-task
            Reporter: Guozhang Wang

Under the following scenario the retry logic can block

1. The last broker's socket closed, sender.handleDisconnect() triggered, put the node as disconnected.

2. In the next sender.run(), since the node is disconnected, remove the partition from ready
set, and call sender.initConnection(), which will not throw exception.

3. So in this round of send, the only request it tries to send to is the metadata request,
to the last broker; and the sender will firstly try to connect to that broker.

4. In selector.poll(), the finishConnect() call will throw exception, and in handleDisconnects(),
inFlight request's batches will be null since it is a metadata request.

5. Now we will go back to 1, and loop forever. Note that this infinite loop can be triggered
even without calling producer.close.

Also, we need to introduce the retry backoff config, otherwise the retries will be exhausted
too soon (in my tests 10 retries can be exhausted in about 600ms).

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