[jira] [Created] (KAFKA-6491) Large uncompacted __consumer_offsets files should not make broker restarts slow

["Mike Mintz (JIRA)" <ji...@apache.org>]

Mike Mintz created KAFKA-6491:
---------------------------------

             Summary: Large uncompacted __consumer_offsets files should not make broker restarts slow
                 Key: KAFKA-6491
                 URL: https://issues.apache.org/jira/browse/KAFKA-6491
             Project: Kafka
          Issue Type: Bug
          Components: offset manager
    Affects Versions: 0.10.2.1
            Reporter: Mike Mintz


Before discovering the {{log.cleaner.enable}} option, we had several Kafka brokers running 0.10.2.1 with ~500GB of __consumer_offsets files. When restarting the kafka process on these brokers, clients were able to successfully produce and consume messages, but clients failed to commit offsets to __consumer_offsets partitions which the restarted broker was leader for. Running jstack indicated the broker was spending its time in GroupMetadataManager.loadGroupsAndOffsets (example stack trace below).

Ideally Kafka brokers would be able to start up much faster in the presence of large __consumer_offsets files.

{noformat}
"group-metadata-manager-0" #57 daemon prio=5 os_prio=0 tid=0x00007ffb54ec3800 nid=0xb9d runnable [0x00007ffa81139000]
   java.lang.Thread.State: RUNNABLE
  at sun.nio.ch.FileDispatcherImpl.pread0(Native Method)
  at sun.nio.ch.FileDispatcherImpl.pread(FileDispatcherImpl.java:52)
  at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:220)
  at sun.nio.ch.IOUtil.read(IOUtil.java:197)
  at sun.nio.ch.FileChannelImpl.readInternal(FileChannelImpl.java:741)
  at sun.nio.ch.FileChannelImpl.read(FileChannelImpl.java:727)
  at org.apache.kafka.common.utils.Utils.readFully(Utils.java:854)
  at org.apache.kafka.common.record.FileRecords.readInto(FileRecords.java:121)
  at kafka.coordinator.GroupMetadataManager.loadGroupsAndOffsets(GroupMetadataManager.scala:427)
  at kafka.coordinator.GroupMetadataManager.kafka$coordinator$GroupMetadataManager$$doLoadGroupsAndOffsets$1(GroupMetadataManager.scala:392)
  at kafka.coordinator.GroupMetadataManager$$anonfun$loadGroupsForPartition$1.apply$mcV$sp(GroupMetadataManager.scala:403)
  at kafka.utils.KafkaScheduler$$anonfun$1.apply$mcV$sp(KafkaScheduler.scala:110)
  at kafka.utils.CoreUtils$$anon$1.run(CoreUtils.scala:57)
  at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
{noformat}



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