Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/13152#discussion_r75426951
--- Diff: core/src/main/scala/org/apache/spark/storage/BlockManager.scala
---
@@ -1088,109 +1108,86 @@ private[spark] class BlockManager(
}
/**
- * Replicate block to another node. Not that this is a blocking call
that returns after
+ * Replicate block to another node. Note that this is a blocking call
that returns after
* the block has been replicated.
+ *
+ * @param blockId
+ * @param data
+ * @param level
+ * @param classTag
*/
private def replicate(
- blockId: BlockId,
- data: ChunkedByteBuffer,
- level: StorageLevel,
- classTag: ClassTag[_]): Unit = {
+ blockId: BlockId,
+ data: ChunkedByteBuffer,
+ level: StorageLevel,
+ classTag: ClassTag[_]): Unit = {
+
val maxReplicationFailures =
conf.getInt("spark.storage.maxReplicationFailures", 1)
- val numPeersToReplicateTo = level.replication - 1
- val peersForReplication = new ArrayBuffer[BlockManagerId]
- val peersReplicatedTo = new ArrayBuffer[BlockManagerId]
- val peersFailedToReplicateTo = new ArrayBuffer[BlockManagerId]
val tLevel = StorageLevel(
useDisk = level.useDisk,
useMemory = level.useMemory,
useOffHeap = level.useOffHeap,
deserialized = level.deserialized,
replication = 1)
+
+ val numPeersToReplicateTo = level.replication - 1
+
val startTime = System.currentTimeMillis
- val random = new Random(blockId.hashCode)
-
- var replicationFailed = false
- var failures = 0
- var done = false
-
- // Get cached list of peers
- peersForReplication ++= getPeers(forceFetch = false)
-
- // Get a random peer. Note that this selection of a peer is
deterministic on the block id.
- // So assuming the list of peers does not change and no replication
failures,
- // if there are multiple attempts in the same node to replicate the
same block,
- // the same set of peers will be selected.
- def getRandomPeer(): Option[BlockManagerId] = {
- // If replication had failed, then force update the cached list of
peers and remove the peers
- // that have been already used
- if (replicationFailed) {
- peersForReplication.clear()
- peersForReplication ++= getPeers(forceFetch = true)
- peersForReplication --= peersReplicatedTo
- peersForReplication --= peersFailedToReplicateTo
- }
- if (!peersForReplication.isEmpty) {
- Some(peersForReplication(random.nextInt(peersForReplication.size)))
- } else {
- None
- }
- }
- // One by one choose a random peer and try uploading the block to it
- // If replication fails (e.g., target peer is down), force the list of
cached peers
- // to be re-fetched from driver and then pick another random peer for
replication. Also
- // temporarily black list the peer for which replication failed.
- //
- // This selection of a peer and replication is continued in a loop
until one of the
- // following 3 conditions is fulfilled:
- // (i) specified number of peers have been replicated to
- // (ii) too many failures in replicating to peers
- // (iii) no peer left to replicate to
- //
- while (!done) {
- getRandomPeer() match {
- case Some(peer) =>
- try {
- val onePeerStartTime = System.currentTimeMillis
- logTrace(s"Trying to replicate $blockId of ${data.size} bytes
to $peer")
- blockTransferService.uploadBlockSync(
- peer.host,
- peer.port,
- peer.executorId,
- blockId,
- new NettyManagedBuffer(data.toNetty),
- tLevel,
- classTag)
- logTrace(s"Replicated $blockId of ${data.size} bytes to $peer
in %s ms"
- .format(System.currentTimeMillis - onePeerStartTime))
- peersReplicatedTo += peer
- peersForReplication -= peer
- replicationFailed = false
- if (peersReplicatedTo.size == numPeersToReplicateTo) {
- done = true // specified number of peers have been
replicated to
- }
- } catch {
- case e: Exception =>
- logWarning(s"Failed to replicate $blockId to $peer, failure
#$failures", e)
- failures += 1
- replicationFailed = true
- peersFailedToReplicateTo += peer
- if (failures > maxReplicationFailures) { // too many
failures in replicating to peers
- done = true
- }
+ var peersForReplication =
+ blockReplicationPrioritizer.prioritize(blockManagerId,
getPeers(false), Set.empty, blockId)
+ var peersReplicatedTo = Set.empty[BlockManagerId]
+ var peersFailedToReplicateTo = Set.empty[BlockManagerId]
--- End diff --
for both peersReplicatedTo and peersFailedToReplicateTo
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