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Improve efficiency of gossip, see #2193 and #2253

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* Essentially as already described in cluster specification,
  but now fully implemented and tested with LargeClusterSpec
* Gossip to nodes with different view (using seen table)
  with certain probability
* Gossip chat, gossip back to sender
* Immediate gossip to joining node
* Updated some tests to reflect current implementation
This commit is contained in:
Patrik Nordwall 2012-06-28 11:36:13 +02:00
parent aca66de732
commit 2da1a912fe
5 changed files with 67 additions and 191 deletions
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40
akka-cluster/src/main/scala/akka/cluster/Cluster.scala
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@ -832,7 +832,10 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
else {
log.info("Cluster Node [{}] - Node [{}] is JOINING", selfAddress, node)
// treat join as initial heartbeat, so that it becomes unavailable if nothing more happens
if (node != selfAddress) failureDetector heartbeat node
if (node != selfAddress) {
failureDetector heartbeat node
gossipTo(node)
}
notifyMembershipChangeListeners(localState, newState)
}
}
@ -974,10 +977,6 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
val mergedGossip = remoteGossip merge localGossip
val versionedMergedGossip = mergedGossip :+ vclockNode
log.debug(
"""Can't establish a causal relationship between "remote" gossip and "local" gossip - Remote[{}] - Local[{}] - merging them into [{}]""",
remoteGossip, localGossip, versionedMergedGossip)
versionedMergedGossip
} else if (remoteGossip.version < localGossip.version) {
@ -1003,8 +1002,20 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
if (!state.compareAndSet(localState, newState)) receiveGossip(from, remoteGossip) // recur if we fail the update
else {
log.debug("Cluster Node [{}] - Receiving gossip from [{}]", selfAddress, from)
if ((winningGossip ne localGossip) && (winningGossip ne remoteGossip))
log.debug(
"""Couldn't establish a causal relationship between "remote" gossip and "local" gossip - Remote[{}] - Local[{}] - merged them into [{}]""",
remoteGossip, localGossip, winningGossip)
_receivedGossipCount.incrementAndGet()
notifyMembershipChangeListeners(localState, newState)
if ((winningGossip ne remoteGossip) || (newState.latestGossip ne remoteGossip)) {
// send back gossip to sender when sender had different view, i.e. merge, or sender had
// older or sender had newer
gossipTo(from)
}
}
}
}
@ -1055,6 +1066,8 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
}
}
private def gossipToDifferentViewProbability: Double = 0.8
/**
* INTERNAL API.
*
@ -1075,8 +1088,21 @@ class Cluster(system: ExtendedActorSystem, val failureDetector: FailureDetector)
val localUnreachableMembers = localGossip.overview.unreachable.toIndexedSeq
val localUnreachableSize = localUnreachableMembers.size
// 1. gossip to alive members
val gossipedToAlive = gossipToRandomNodeOf(localMemberAddresses)
// 1. gossip to a random alive member with preference to a member
// with older or newer gossip version
val nodesWithdifferentView = {
val localMemberAddressesSet = localGossip.members map { _.address }
for {
(address, version) ← localGossip.overview.seen
if localMemberAddressesSet contains address
if version != localGossip.version
} yield address
}
val gossipedToAlive =
if (nodesWithdifferentView.nonEmpty && ThreadLocalRandom.current.nextDouble() < gossipToDifferentViewProbability)
gossipToRandomNodeOf(nodesWithdifferentView.toIndexedSeq)
else
gossipToRandomNodeOf(localMemberAddresses)
// 2. gossip to a deputy nodes for facilitating partition healing
val deputies = deputyNodes(localMemberAddresses)