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Posted to commits@kafka.apache.org by jg...@apache.org on 2018/05/18 20:34:54 UTC

[kafka] branch 1.1 updated: KAFKA-6917; Process txn completion asynchronously to avoid deadlock (#5036)

This is an automated email from the ASF dual-hosted git repository.

jgus pushed a commit to branch 1.1
in repository https://gitbox.apache.org/repos/asf/kafka.git


The following commit(s) were added to refs/heads/1.1 by this push:
     new be58d73  KAFKA-6917; Process txn completion asynchronously to avoid deadlock (#5036)
be58d73 is described below

commit be58d7370667e8f0670a3e480674794e6cbb8231
Author: Rajini Sivaram <ra...@googlemail.com>
AuthorDate: Fri May 18 21:30:12 2018 +0100

    KAFKA-6917; Process txn completion asynchronously to avoid deadlock (#5036)
    
    Reviewers: Guozhang Wang <wa...@gmail.com>, Jason Gustafson <ja...@confluent.io>
---
 .../kafka/coordinator/group/GroupCoordinator.scala | 11 ++++----
 .../coordinator/group/GroupMetadataManager.scala   | 30 ++++++++++++++++------
 core/src/main/scala/kafka/server/KafkaApis.scala   |  2 +-
 .../group/GroupCoordinatorConcurrencyTest.scala    | 24 +++++++++--------
 .../coordinator/group/GroupCoordinatorTest.scala   | 23 +++++++++++------
 5 files changed, 56 insertions(+), 34 deletions(-)

diff --git a/core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala b/core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala
index 5ae8552..6cc0a41 100644
--- a/core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala
+++ b/core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala
@@ -81,8 +81,7 @@ class GroupCoordinator(val brokerId: Int,
    */
   def startup(enableMetadataExpiration: Boolean = true) {
     info("Starting up.")
-    if (enableMetadataExpiration)
-      groupManager.enableMetadataExpiration()
+    groupManager.startup(enableMetadataExpiration)
     isActive.set(true)
     info("Startup complete.")
   }
@@ -488,12 +487,12 @@ class GroupCoordinator(val brokerId: Int,
     }
   }
 
-  def handleTxnCompletion(producerId: Long,
-                          offsetsPartitions: Iterable[TopicPartition],
-                          transactionResult: TransactionResult) {
+  def scheduleHandleTxnCompletion(producerId: Long,
+                                  offsetsPartitions: Iterable[TopicPartition],
+                                  transactionResult: TransactionResult) {
     require(offsetsPartitions.forall(_.topic == Topic.GROUP_METADATA_TOPIC_NAME))
     val isCommit = transactionResult == TransactionResult.COMMIT
-    groupManager.handleTxnCompletion(producerId, offsetsPartitions.map(_.partition).toSet, isCommit)
+    groupManager.scheduleHandleTxnCompletion(producerId, offsetsPartitions.map(_.partition).toSet, isCommit)
   }
 
   private def doCommitOffsets(group: GroupMetadata,
diff --git a/core/src/main/scala/kafka/coordinator/group/GroupMetadataManager.scala b/core/src/main/scala/kafka/coordinator/group/GroupMetadataManager.scala
index 7d4fe03..44a9369 100644
--- a/core/src/main/scala/kafka/coordinator/group/GroupMetadataManager.scala
+++ b/core/src/main/scala/kafka/coordinator/group/GroupMetadataManager.scala
@@ -135,13 +135,14 @@ class GroupMetadataManager(brokerId: Int,
       })
     })
 
-  def enableMetadataExpiration() {
+  def startup(enableMetadataExpiration: Boolean) {
     scheduler.startup()
-
-    scheduler.schedule(name = "delete-expired-group-metadata",
-      fun = cleanupGroupMetadata,
-      period = config.offsetsRetentionCheckIntervalMs,
-      unit = TimeUnit.MILLISECONDS)
+    if (enableMetadataExpiration) {
+      scheduler.schedule(name = "delete-expired-group-metadata",
+        fun = cleanupGroupMetadata,
+        period = config.offsetsRetentionCheckIntervalMs,
+        unit = TimeUnit.MILLISECONDS)
+    }
   }
 
   def currentGroups: Iterable[GroupMetadata] = groupMetadataCache.values
@@ -794,7 +795,20 @@ class GroupMetadataManager(brokerId: Int,
     info(s"Removed $offsetsRemoved expired offsets in ${time.milliseconds() - startMs} milliseconds.")
   }
 
-  def handleTxnCompletion(producerId: Long, completedPartitions: Set[Int], isCommit: Boolean) {
+  /**
+   * Complete pending transactional offset commits of the groups of `producerId` from the provided
+   * `completedPartitions`. This method is invoked when a commit or abort marker is fully written
+   * to the log. It may be invoked when a group lock is held by the caller, for instance when delayed
+   * operations are completed while appending offsets for a group. Since we need to acquire one or
+   * more group metadata locks to handle transaction completion, this operation is scheduled on
+   * the scheduler thread to avoid deadlocks.
+   */
+  def scheduleHandleTxnCompletion(producerId: Long, completedPartitions: Set[Int], isCommit: Boolean): Unit = {
+    scheduler.schedule(s"handleTxnCompletion-$producerId", () =>
+      handleTxnCompletion(producerId, completedPartitions, isCommit))
+  }
+
+  private[group] def handleTxnCompletion(producerId: Long, completedPartitions: Set[Int], isCommit: Boolean): Unit = {
     val pendingGroups = groupsBelongingToPartitions(producerId, completedPartitions)
     pendingGroups.foreach { case (groupId) =>
       getGroup(groupId) match {
@@ -803,7 +817,7 @@ class GroupMetadataManager(brokerId: Int,
             group.completePendingTxnOffsetCommit(producerId, isCommit)
             removeProducerGroup(producerId, groupId)
           }
-       }
+        }
         case _ =>
           info(s"Group $groupId has moved away from $brokerId after transaction marker was written but before the " +
             s"cache was updated. The cache on the new group owner will be updated instead.")
diff --git a/core/src/main/scala/kafka/server/KafkaApis.scala b/core/src/main/scala/kafka/server/KafkaApis.scala
index 9e79afa..5d68c98 100644
--- a/core/src/main/scala/kafka/server/KafkaApis.scala
+++ b/core/src/main/scala/kafka/server/KafkaApis.scala
@@ -1623,7 +1623,7 @@ class KafkaApis(val requestChannel: RequestChannel,
         // as soon as the end transaction marker has been written for a transactional offset commit,
         // call to the group coordinator to materialize the offsets into the cache
         try {
-          groupCoordinator.handleTxnCompletion(producerId, successfulOffsetsPartitions, result)
+          groupCoordinator.scheduleHandleTxnCompletion(producerId, successfulOffsetsPartitions, result)
         } catch {
           case e: Exception =>
             error(s"Received an exception while trying to update the offsets cache on transaction marker append", e)
diff --git a/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorConcurrencyTest.scala b/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorConcurrencyTest.scala
index 44e1356..befd22a 100644
--- a/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorConcurrencyTest.scala
+++ b/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorConcurrencyTest.scala
@@ -27,7 +27,7 @@ import kafka.server.{ DelayedOperationPurgatory, KafkaConfig }
 import org.apache.kafka.common.TopicPartition
 import org.apache.kafka.common.internals.Topic
 import org.apache.kafka.common.protocol.Errors
-import org.apache.kafka.common.requests.{ JoinGroupRequest, TransactionResult }
+import org.apache.kafka.common.requests.JoinGroupRequest
 import org.easymock.EasyMock
 import org.junit.Assert._
 import org.junit.{ After, Before, Test }
@@ -117,7 +117,6 @@ class GroupCoordinatorConcurrencyTest extends AbstractCoordinatorConcurrencyTest
     verifyConcurrentRandomSequences(createGroupMembers, allOperationsWithTxn)
   }
 
-
   abstract class GroupOperation[R, C] extends Operation {
     val responseFutures = new ConcurrentHashMap[GroupMember, Future[R]]()
 
@@ -228,8 +227,17 @@ class GroupCoordinatorConcurrencyTest extends AbstractCoordinatorConcurrencyTest
       val offsets = immutable.Map(tp -> OffsetAndMetadata(1))
       val producerId = 1000L
       val producerEpoch : Short = 2
+      // When transaction offsets are appended to the log, transactions may be scheduled for
+      // completion. Since group metadata locks are acquired for transaction completion, include
+      // this in the callback to test that there are no deadlocks.
+      def callbackWithTxnCompletion(errors: Map[TopicPartition, Errors]): Unit = {
+        val offsetsPartitions = (0 to numPartitions).map(new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, _))
+        groupCoordinator.groupManager.scheduleHandleTxnCompletion(producerId,
+          offsetsPartitions.map(_.partition).toSet, isCommit = random.nextBoolean)
+        responseCallback(errors)
+      }
       groupCoordinator.handleTxnCommitOffsets(member.group.groupId,
-          producerId, producerEpoch, offsets, responseCallback)
+          producerId, producerEpoch, offsets, callbackWithTxnCompletion)
     }
   }
 
@@ -241,19 +249,14 @@ class GroupCoordinatorConcurrencyTest extends AbstractCoordinatorConcurrencyTest
     override def runWithCallback(member: GroupMember, responseCallback: CompleteTxnCallback): Unit = {
       val producerId = 1000L
       val offsetsPartitions = (0 to numPartitions).map(new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, _))
-      groupCoordinator.handleTxnCompletion(producerId, offsetsPartitions, transactionResult(member.group.groupId))
+      groupCoordinator.groupManager.handleTxnCompletion(producerId,
+        offsetsPartitions.map(_.partition).toSet, isCommit = random.nextBoolean)
       responseCallback(Errors.NONE)
     }
     override def awaitAndVerify(member: GroupMember): Unit = {
       val error = await(member, 500)
       assertEquals(Errors.NONE, error)
     }
-    // Test both commit and abort. Group ids used in the test have the format <prefix><index>
-    // Use the last digit of the index to decide between commit and abort.
-    private def transactionResult(groupId: String): TransactionResult = {
-      val lastDigit = groupId(groupId.length - 1).toInt
-      if (lastDigit % 2 == 0) TransactionResult.COMMIT else TransactionResult.ABORT
-    }
   }
 
   class LeaveGroupOperation extends GroupOperation[LeaveGroupCallbackParams, LeaveGroupCallback] {
@@ -273,7 +276,6 @@ class GroupCoordinatorConcurrencyTest extends AbstractCoordinatorConcurrencyTest
 
 object GroupCoordinatorConcurrencyTest {
 
-
   type JoinGroupCallback = JoinGroupResult => Unit
   type SyncGroupCallbackParams = (Array[Byte], Errors)
   type SyncGroupCallback = (Array[Byte], Errors) => Unit
diff --git a/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorTest.scala b/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorTest.scala
index 2c9e81d..8529bf9 100644
--- a/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorTest.scala
+++ b/core/src/test/scala/unit/kafka/coordinator/group/GroupCoordinatorTest.scala
@@ -841,7 +841,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     val offsetsTopic = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, groupPartitionId)
 
     // Send commit marker.
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.COMMIT)
+    handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.COMMIT)
 
     // Validate that committed offset is materialized.
     val (secondReqError, secondReqPartitionData) = groupCoordinator.handleFetchOffsets(groupId, Some(Seq(tp)))
@@ -866,7 +866,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     val offsetsTopic = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, groupPartitionId)
 
     // Validate that the pending commit is discarded.
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.ABORT)
+    handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.ABORT)
 
     val (secondReqError, secondReqPartitionData) = groupCoordinator.handleFetchOffsets(groupId, Some(Seq(tp)))
     assertEquals(Errors.NONE, secondReqError)
@@ -888,14 +888,14 @@ class GroupCoordinatorTest extends JUnitSuite {
     assertEquals(Some(OffsetFetchResponse.INVALID_OFFSET), partitionData.get(tp).map(_.offset))
 
     val offsetsTopic = new TopicPartition(Topic.GROUP_METADATA_TOPIC_NAME, groupPartitionId)
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.ABORT)
+    handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.ABORT)
 
     val (secondReqError, secondReqPartitionData) = groupCoordinator.handleFetchOffsets(groupId, Some(Seq(tp)))
     assertEquals(Errors.NONE, secondReqError)
     assertEquals(Some(OffsetFetchResponse.INVALID_OFFSET), secondReqPartitionData.get(tp).map(_.offset))
 
     // Ignore spurious commit.
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.COMMIT)
+    handleTxnCompletion(producerId, List(offsetsTopic), TransactionResult.COMMIT)
 
     val (thirdReqError, thirdReqPartitionData) = groupCoordinator.handleFetchOffsets(groupId, Some(Seq(tp)))
     assertEquals(Errors.NONE, thirdReqError)
@@ -932,7 +932,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     assertEquals(Errors.NONE, commitOffsetResults(1)(partitions(1)))
 
     // We got a commit for only one __consumer_offsets partition. We should only materialize it's group offsets.
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetTopicPartitions(0)), TransactionResult.COMMIT)
+    handleTxnCompletion(producerId, List(offsetTopicPartitions(0)), TransactionResult.COMMIT)
     groupCoordinator.handleFetchOffsets(groupIds(0), Some(partitions)) match {
       case (error, partData) =>
         errors.append(error)
@@ -958,7 +958,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     assertEquals(Some(OffsetFetchResponse.INVALID_OFFSET), partitionData(1).get(partitions(1)).map(_.offset))
 
     // Now we receive the other marker.
-    groupCoordinator.handleTxnCompletion(producerId, List(offsetTopicPartitions(1)), TransactionResult.COMMIT)
+    handleTxnCompletion(producerId, List(offsetTopicPartitions(1)), TransactionResult.COMMIT)
     errors.clear()
     partitionData.clear()
     groupCoordinator.handleFetchOffsets(groupIds(0), Some(partitions)) match {
@@ -1008,7 +1008,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     assertEquals(Errors.NONE, commitOffsetResults(1)(partitions(1)))
 
     // producer0 commits its transaction.
-    groupCoordinator.handleTxnCompletion(producerIds(0), List(offsetTopicPartition), TransactionResult.COMMIT)
+    handleTxnCompletion(producerIds(0), List(offsetTopicPartition), TransactionResult.COMMIT)
     groupCoordinator.handleFetchOffsets(groupId, Some(partitions)) match {
       case (error, partData) =>
         errors.append(error)
@@ -1023,7 +1023,7 @@ class GroupCoordinatorTest extends JUnitSuite {
     assertEquals(Some(OffsetFetchResponse.INVALID_OFFSET), partitionData(0).get(partitions(1)).map(_.offset))
 
     // producer1 now commits its transaction.
-    groupCoordinator.handleTxnCompletion(producerIds(1), List(offsetTopicPartition), TransactionResult.COMMIT)
+    handleTxnCompletion(producerIds(1), List(offsetTopicPartition), TransactionResult.COMMIT)
 
     groupCoordinator.handleFetchOffsets(groupId, Some(partitions)) match {
       case (error, partData) =>
@@ -1629,4 +1629,11 @@ class GroupCoordinatorTest extends JUnitSuite {
     Await.result(responseFuture, Duration(40, TimeUnit.MILLISECONDS))
   }
 
+  def handleTxnCompletion(producerId: Long,
+                          offsetsPartitions: Iterable[TopicPartition],
+                          transactionResult: TransactionResult): Unit = {
+    val isCommit = transactionResult == TransactionResult.COMMIT
+    groupCoordinator.groupManager.handleTxnCompletion(producerId, offsetsPartitions.map(_.partition).toSet, isCommit)
+  }
+
 }

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