Remove AbstractRaftActorBehavior#findClientRequestTracker()

This is an unused method, remove it. Also add some documentation
around trackers and simplify tracker-based messages.

Change-Id: Ia0afca836bd56b75dcdb74d6c6b309a9eeaa75ee
Signed-off-by: Robert Varga <rovarga@cisco.com>

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java
index d914154f8bb5565c64836f7f97282a7390aa37e4..6779414f8c50c6288da1470b8b0656dc969095c7 100644 (file)
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractLeader.java
@@ -25,6 +25,7 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
+import java.util.Queue;
 import javax.annotation.Nullable;
 import org.opendaylight.controller.cluster.raft.ClientRequestTracker;
 import org.opendaylight.controller.cluster.raft.ClientRequestTrackerImpl;
@@ -84,13 +85,18 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
     private final Map<String, FollowerLogInformation> followerToLog = new HashMap<>();
     private final Map<String, FollowerToSnapshot> mapFollowerToSnapshot = new HashMap<>();
 
-    private Cancellable heartbeatSchedule = null;
-
-    private final Collection<ClientRequestTracker> trackerList = new LinkedList<>();
-
-    private int minReplicationCount;
+    /**
+     * Lookup table for request contexts based on journal index. We could use a {@link Map} here, but we really
+     * expect the entries to be modified in sequence, hence we open-code the lookup.
+     *
+     * TODO: Evaluate the use of ArrayDeque(), as that has lower memory overhead. Non-head removals are more costly,
+     *       but we already expect those to be far from frequent.
+     */
+    private final Queue<ClientRequestTracker> trackers = new LinkedList<>();
 
+    private Cancellable heartbeatSchedule = null;
     private Optional<SnapshotHolder> snapshot;
+    private int minReplicationCount;
 
     protected AbstractLeader(RaftActorContext context, RaftState state) {
         super(context, state);
@@ -325,7 +331,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
 
     @Override
     protected ClientRequestTracker removeClientRequestTracker(long logIndex) {
-        final Iterator<ClientRequestTracker> it = trackerList.iterator();
+        final Iterator<ClientRequestTracker> it = trackers.iterator();
         while (it.hasNext()) {
             final ClientRequestTracker t = it.next();
             if (t.getIndex() == logIndex) {
@@ -337,16 +343,6 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
         return null;
     }
 
-    @Override
-    protected ClientRequestTracker findClientRequestTracker(long logIndex) {
-        for (ClientRequestTracker tracker : trackerList) {
-            if (tracker.getIndex() == logIndex) {
-                return tracker;
-            }
-        }
-        return null;
-    }
-
     @Override
     protected RaftActorBehavior handleRequestVoteReply(ActorRef sender,
         RequestVoteReply requestVoteReply) {
@@ -493,7 +489,7 @@ public abstract class AbstractLeader extends AbstractRaftActorBehavior {
 
         // Create a tracker entry we will use this later to notify the
         // client actor
-        trackerList.add(
+        trackers.add(
             new ClientRequestTrackerImpl(replicate.getClientActor(),
                 replicate.getIdentifier(),
                 logIndex)

diff --git a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
index 106678e4742a666617a280f79399f91c73286126..98cbd7b38179710e59733a0b08a2e53692e84f29 100644 (file)
--- a/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
+++ b/opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/behaviors/AbstractRaftActorBehavior.java
@@ -25,7 +25,6 @@ import org.opendaylight.controller.cluster.raft.messages.AppendEntries;
 import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
 import org.opendaylight.controller.cluster.raft.messages.RequestVote;
 import org.opendaylight.controller.cluster.raft.messages.RequestVoteReply;
-import org.opendaylight.yangtools.concepts.Identifier;
 import org.slf4j.Logger;
 import scala.concurrent.duration.FiniteDuration;
 
@@ -314,14 +313,6 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
         return context.getReplicatedLog().lastIndex();
     }
 
-    /**
-     * @param logIndex
-     * @return the client request tracker for the specified logIndex
-     */
-    protected ClientRequestTracker findClientRequestTracker(long logIndex) {
-        return null;
-    }
-
     /**
      * @param logIndex
      * @return the client request tracker for the specified logIndex
@@ -330,7 +321,6 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
         return null;
     }
 
-
     /**
      *
      * @return log index from the previous to last entry in the log
@@ -365,22 +355,21 @@ public abstract class AbstractRaftActorBehavior implements RaftActorBehavior {
         long newLastApplied = context.getLastApplied();
         // Now maybe we apply to the state machine
         for (long i = context.getLastApplied() + 1; i < index + 1; i++) {
-            final ActorRef clientActor;
-            final Identifier identifier;
-            final ClientRequestTracker tracker = removeClientRequestTracker(i);
-            if (tracker != null) {
-                clientActor = tracker.getClientActor();
-                identifier = tracker.getIdentifier();
-            } else {
-                clientActor = null;
-                identifier = null;
-            }
 
             ReplicatedLogEntry replicatedLogEntry = context.getReplicatedLog().get(i);
             if (replicatedLogEntry != null) {
                 // Send a local message to the local RaftActor (it's derived class to be
                 // specific to apply the log to it's index)
-                actor().tell(new ApplyState(clientActor, identifier, replicatedLogEntry), actor());
+
+                final ApplyState msg;
+                final ClientRequestTracker tracker = removeClientRequestTracker(i);
+                if (tracker != null) {
+                    msg = new ApplyState(tracker.getClientActor(), tracker.getIdentifier(), replicatedLogEntry);
+                } else {
+                    msg = new ApplyState(null, null, replicatedLogEntry);
+                }
+
+                actor().tell(msg, actor());
                 newLastApplied = i;
             } else {
                 //if one index is not present in the log, no point in looping