X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-distributed-datastore%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fdatabroker%2Factors%2Fdds%2FAbstractProxyTransaction.java;h=ac91f2d0413ad8aca71391ba86921c92dc1b008b;hp=83ba07b69ac8f6e3ed253d18e420315065069e4d;hb=9b4c07ca27b2c3c7ca5d5e790aa1f121ce4857f3;hpb=3ee40198347cfb53bd0ce12ffd625cff8ed2383b

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/AbstractProxyTransaction.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/AbstractProxyTransaction.java
index 83ba07b69a..ac91f2d041 100644
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/AbstractProxyTransaction.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/databroker/actors/dds/AbstractProxyTransaction.java
@@ -13,6 +13,7 @@ import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Throwables;
 import com.google.common.base.Verify;
+import com.google.common.collect.Iterables;
 import com.google.common.util.concurrent.CheckedFuture;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.SettableFuture;
@@ -29,6 +30,7 @@ import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.NotThreadSafe;
 import org.opendaylight.controller.cluster.access.client.ConnectionEntry;
 import org.opendaylight.controller.cluster.access.commands.AbstractLocalTransactionRequest;
+import org.opendaylight.controller.cluster.access.commands.IncrementTransactionSequenceRequest;
 import org.opendaylight.controller.cluster.access.commands.TransactionAbortRequest;
 import org.opendaylight.controller.cluster.access.commands.TransactionAbortSuccess;
 import org.opendaylight.controller.cluster.access.commands.TransactionCanCommitSuccess;
@@ -69,18 +71,30 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      */
     @NotThreadSafe
     private static final class IncrementSequence {
-        private long delta = 1;
+        private final long sequence;
+        private long delta = 0;
+
+        IncrementSequence(final long sequence) {
+            this.sequence = sequence;
+        }
 
         long getDelta() {
             return delta;
         }
 
+        long getSequence() {
+            return sequence;
+        }
+
         void incrementDelta() {
             delta++;
         }
     }
 
-    // Generic state base class. Direct instances are used for fast paths, sub-class is used for successor transitions
+    /**
+     * Base class for representing logical state of this proxy. See individual instantiations and {@link SuccessorState}
+     * for details.
+     */
     private static class State {
         private final String string;
 
@@ -94,14 +108,27 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         }
     }
 
-    // State class used when a successor has interfered. Contains coordinator latch, the successor and previous state
-    private static final class SuccessorState extends State {
+    /**
+     * State class used when a successor has interfered. Contains coordinator latch, the successor and previous state.
+     * This is a temporary state introduced during reconnection process and is necessary for correct state hand-off
+     * between the old connection (potentially being accessed by the user) and the new connection (being cleaned up
+     * by the actor.
+     *
+     * <p>
+     * When a user operation encounters this state, it synchronizes on the it and wait until reconnection completes,
+     * at which point the request is routed to the successor transaction. This is a relatively heavy-weight solution
+     * to the problem of state transfer, but the user will observe it only if the race condition is hit.
+     */
+    private static class SuccessorState extends State {
         private final CountDownLatch latch = new CountDownLatch(1);
         private AbstractProxyTransaction successor;
         private State prevState;
 
+        // SUCCESSOR + DONE
+        private boolean done;
+
         SuccessorState() {
-            super("successor");
+            super("SUCCESSOR");
         }
 
         // Synchronize with succession process and return the successor
@@ -124,7 +151,8 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         }
 
         void setPrevState(final State prevState) {
-            Verify.verify(this.prevState == null);
+            Verify.verify(this.prevState == null, "Attempted to set previous state to %s when we already have %s",
+                    prevState, this.prevState);
             this.prevState = Preconditions.checkNotNull(prevState);
         }
 
@@ -134,9 +162,18 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         }
 
         void setSuccessor(final AbstractProxyTransaction successor) {
-            Verify.verify(this.successor == null);
+            Verify.verify(this.successor == null, "Attempted to set successor to %s when we already have %s",
+                    successor, this.successor);
             this.successor = Preconditions.checkNotNull(successor);
         }
+
+        boolean isDone() {
+            return done;
+        }
+
+        void setDone() {
+            done = true;
+        }
     }
 
     private static final Logger LOG = LoggerFactory.getLogger(AbstractProxyTransaction.class);
@@ -144,9 +181,41 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
             AtomicIntegerFieldUpdater.newUpdater(AbstractProxyTransaction.class, "sealed");
     private static final AtomicReferenceFieldUpdater<AbstractProxyTransaction, State> STATE_UPDATER =
             AtomicReferenceFieldUpdater.newUpdater(AbstractProxyTransaction.class, State.class, "state");
-    private static final State OPEN = new State("open");
-    private static final State SEALED = new State("sealed");
-    private static final State FLUSHED = new State("flushed");
+
+    /**
+     * Transaction has been open and is being actively worked on.
+     */
+    private static final State OPEN = new State("OPEN");
+
+    /**
+     * Transaction has been sealed by the user, but it has not completed flushing to the backed, yet. This is
+     * a transition state, as we are waiting for the user to initiate commit procedures.
+     *
+     * <p>
+     * Since the reconnect mechanics relies on state replay for transactions, this state needs to be flushed into the
+     * queue to re-create state in successor transaction (which may be based on different messages as locality may have
+     * changed). Hence the transition to {@link #FLUSHED} state needs to be handled in a thread-safe manner.
+     */
+    private static final State SEALED = new State("SEALED");
+
+    /**
+     * Transaction state has been flushed into the queue, i.e. it is visible by the successor and potentially
+     * the backend. At this point the transaction does not hold any state besides successful requests, all other state
+     * is held either in the connection's queue or the successor object.
+     *
+     * <p>
+     * Transition to this state indicates we have all input from the user we need to initiate the correct commit
+     * protocol.
+     */
+    private static final State FLUSHED = new State("FLUSHED");
+
+    /**
+     * Transaction state has been completely resolved, we have received confirmation of the transaction fate from
+     * the backend. The only remaining task left to do is finishing up the state cleanup, which is done via purge
+     * request. We need to hang on to the transaction until that is done, as we have to make sure backend completes
+     * purging its state -- otherwise we could have a leak on the backend.
+     */
+    private static final State DONE = new State("DONE");
 
     // Touched from client actor thread only
     private final Deque<Object> successfulRequests = new ArrayDeque<>();
@@ -186,11 +255,18 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         this.parent = Preconditions.checkNotNull(parent);
     }
 
+    final void executeInActor(final Runnable command) {
+        parent.context().executeInActor(behavior -> {
+            command.run();
+            return behavior;
+        });
+    }
+
     final ActorRef localActor() {
         return parent.localActor();
     }
 
-    private void incrementSequence(final long delta) {
+    final void incrementSequence(final long delta) {
         sequence += delta;
         LOG.debug("Transaction {} incremented sequence to {}", this, sequence);
     }
@@ -229,6 +305,12 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         return doRead(path);
     }
 
+    final void enqueueRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback,
+            final long enqueuedTicks) {
+        LOG.debug("Transaction proxy {} enqueing request {} callback {}", this, request, callback);
+        parent.enqueueRequest(request, callback, enqueuedTicks);
+    }
+
     final void sendRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback) {
         LOG.debug("Transaction proxy {} sending request {} callback {}", this, request, callback);
         parent.sendRequest(request, callback);
@@ -291,12 +373,12 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
         successfulRequests.add(Verify.verifyNotNull(req));
     }
 
-    final void recordFinishedRequest() {
+    final void recordFinishedRequest(final Response<?, ?> response) {
         final Object last = successfulRequests.peekLast();
         if (last instanceof IncrementSequence) {
             ((IncrementSequence) last).incrementDelta();
         } else {
-            successfulRequests.addLast(new IncrementSequence());
+            successfulRequests.addLast(new IncrementSequence(response.getSequence()));
         }
     }
 
@@ -306,14 +388,18 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      */
     final void abort() {
         checkNotSealed();
-        doAbort();
         parent.abortTransaction(this);
+
+        sendRequest(abortRequest(), resp -> {
+            LOG.debug("Transaction {} abort completed with {}", getIdentifier(), resp);
+            enqueuePurge();
+        });
     }
 
     final void abort(final VotingFuture<Void> ret) {
         checkSealed();
 
-        sendAbort(t -> {
+        sendDoAbort(t -> {
             if (t instanceof TransactionAbortSuccess) {
                 ret.voteYes();
             } else if (t instanceof RequestFailure) {
@@ -324,11 +410,29 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
 
             // This is a terminal request, hence we do not need to record it
             LOG.debug("Transaction {} abort completed", this);
-            purge();
+            enqueuePurge();
         });
     }
 
-    final void sendAbort(final Consumer<Response<?, ?>> callback) {
+    final void enqueueAbort(final Consumer<Response<?, ?>> callback, final long enqueuedTicks) {
+        checkNotSealed();
+        parent.abortTransaction(this);
+
+        enqueueRequest(abortRequest(), resp -> {
+            LOG.debug("Transaction {} abort completed with {}", getIdentifier(), resp);
+            // Purge will be sent by the predecessor's callback
+            if (callback != null) {
+                callback.accept(resp);
+            }
+        }, enqueuedTicks);
+    }
+
+    final void enqueueDoAbort(final Consumer<Response<?, ?>> callback, final long enqueuedTicks) {
+        enqueueRequest(new TransactionAbortRequest(getIdentifier(), nextSequence(), localActor()), callback,
+            enqueuedTicks);
+    }
+
+    final void sendDoAbort(final Consumer<Response<?, ?>> callback) {
         sendRequest(new TransactionAbortRequest(getIdentifier(), nextSequence(), localActor()), callback);
     }
 
@@ -357,7 +461,7 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
 
                     // This is a terminal request, hence we do not need to record it
                     LOG.debug("Transaction {} directCommit completed", this);
-                    purge();
+                    enqueuePurge();
                 });
 
                 return ret;
@@ -451,18 +555,46 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
             }
 
             LOG.debug("Transaction {} doCommit completed", this);
-            purge();
+
+            // Needed for ProxyHistory$Local data tree rebase points.
+            parent.completeTransaction(this);
+
+            enqueuePurge();
         });
     }
 
-    void purge() {
+    private void enqueuePurge() {
+        enqueuePurge(null);
+    }
+
+    final void enqueuePurge(final Consumer<Response<?, ?>> callback) {
+        // Purge request are dispatched internally, hence should not wait
+        enqueuePurge(callback, parent.currentTime());
+    }
+
+    final void enqueuePurge(final Consumer<Response<?, ?>> callback, final long enqueuedTicks) {
+        LOG.debug("{}: initiating purge", this);
+
+        final State prev = state;
+        if (prev instanceof SuccessorState) {
+            ((SuccessorState) prev).setDone();
+        } else {
+            final boolean success = STATE_UPDATER.compareAndSet(this, prev, DONE);
+            if (!success) {
+                LOG.warn("{}: moved from state {} while we were purging it", this, prev);
+            }
+        }
+
         successfulRequests.clear();
 
-        final TransactionRequest<?> req = new TransactionPurgeRequest(getIdentifier(), nextSequence(), localActor());
-        sendRequest(req, t -> {
-            LOG.debug("Transaction {} purge completed", this);
-            parent.completeTransaction(this);
-        });
+        enqueueRequest(new TransactionPurgeRequest(getIdentifier(), nextSequence(), localActor()), resp -> {
+            LOG.debug("{}: purge completed", this);
+            parent.purgeTransaction(this);
+
+            if (callback != null) {
+                callback.accept(resp);
+            }
+        }, enqueuedTicks);
     }
 
     // Called with the connection unlocked
@@ -483,23 +615,40 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
     }
 
     // Called with the connection locked
-    final void replayMessages(final AbstractProxyTransaction successor,
-            final Iterable<ConnectionEntry> enqueuedEntries) {
+    final void replayMessages(final ProxyHistory successorHistory, final Iterable<ConnectionEntry> enqueuedEntries) {
         final SuccessorState local = getSuccessorState();
+        final State prevState = local.getPrevState();
+
+        final AbstractProxyTransaction successor = successorHistory.createTransactionProxy(getIdentifier(),
+            isSnapshotOnly());
+        LOG.debug("{} created successor transaction proxy {}", this, successor);
         local.setSuccessor(successor);
 
         // Replay successful requests first
-        for (Object obj : successfulRequests) {
-            if (obj instanceof TransactionRequest) {
-                LOG.debug("Forwarding successful request {} to successor {}", obj, successor);
-                successor.replay((TransactionRequest<?>) obj, response -> { });
-            } else {
-                Verify.verify(obj instanceof IncrementSequence);
-                successor.incrementSequence(((IncrementSequence) obj).getDelta());
+        if (!successfulRequests.isEmpty()) {
+            // We need to find a good timestamp to use for successful requests, as we do not want to time them out
+            // nor create timing inconsistencies in the queue -- requests are expected to be ordered by their enqueue
+            // time. We will pick the time of the first entry available. If there is none, we will just use current
+            // time, as all other requests will get enqueued afterwards.
+            final ConnectionEntry firstInQueue = Iterables.getFirst(enqueuedEntries, null);
+            final long now = firstInQueue != null ? firstInQueue.getEnqueuedTicks() : parent.currentTime();
+
+            for (Object obj : successfulRequests) {
+                if (obj instanceof TransactionRequest) {
+                    LOG.debug("Forwarding successful request {} to successor {}", obj, successor);
+                    successor.replayRequest((TransactionRequest<?>) obj, resp -> { }, now);
+                } else {
+                    Verify.verify(obj instanceof IncrementSequence);
+                    final IncrementSequence increment = (IncrementSequence) obj;
+                    successor.replayRequest(new IncrementTransactionSequenceRequest(getIdentifier(),
+                        increment.getSequence(), localActor(), isSnapshotOnly(), increment.getDelta()), resp -> { },
+                        now);
+                    LOG.debug("Incrementing sequence {} to successor {}", obj, successor);
+                }
             }
+            LOG.debug("{} replayed {} successful requests", getIdentifier(), successfulRequests.size());
+            successfulRequests.clear();
         }
-        LOG.debug("{} replayed {} successful requests", getIdentifier(), successfulRequests.size());
-        successfulRequests.clear();
 
         // Now replay whatever is in the connection
         final Iterator<ConnectionEntry> it = enqueuedEntries.iterator();
@@ -509,8 +658,8 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
 
             if (getIdentifier().equals(req.getTarget())) {
                 Verify.verify(req instanceof TransactionRequest, "Unhandled request %s", req);
-                LOG.debug("Forwarding queued request {} to successor {}", req, successor);
-                successor.replay((TransactionRequest<?>) req, e.getCallback());
+                LOG.debug("Replaying queued request {} to successor {}", req, successor);
+                successor.replayRequest((TransactionRequest<?>) req, e.getCallback(), e.getEnqueuedTicks());
                 it.remove();
             }
         }
@@ -520,7 +669,6 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
          * reconnecting have been forced to slow paths, which will be unlocked once we unblock the state latch
          * at the end of this method.
          */
-        final State prevState = local.getPrevState();
         if (SEALED.equals(prevState)) {
             LOG.debug("Proxy {} reconnected while being sealed, propagating state to successor {}", this, successor);
             flushState(successor);
@@ -537,12 +685,14 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      *
      * @param request Request which needs to be forwarded
      * @param callback Callback to be invoked once the request completes
+     * @param enqueuedTicks ticker-based time stamp when the request was enqueued
      */
-    private void replay(TransactionRequest<?> request, Consumer<Response<?, ?>> callback) {
+    private void replayRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback,
+            final long enqueuedTicks) {
         if (request instanceof AbstractLocalTransactionRequest) {
-            handleForwardedLocalRequest((AbstractLocalTransactionRequest<?>) request, callback);
+            handleReplayedLocalRequest((AbstractLocalTransactionRequest<?>) request, callback, enqueuedTicks);
         } else {
-            handleForwardedRemoteRequest(request, callback);
+            handleReplayedRemoteRequest(request, callback, enqueuedTicks);
         }
     }
 
@@ -563,8 +713,11 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      * @param callback Original callback
      */
     final void forwardRequest(final TransactionRequest<?> request, final Consumer<Response<?, ?>> callback) {
-        final AbstractProxyTransaction successor = getSuccessorState().getSuccessor();
+        forwardToSuccessor(getSuccessorState().getSuccessor(), request, callback);
+    }
 
+    final void forwardToSuccessor(final AbstractProxyTransaction successor, final TransactionRequest<?> request,
+            final Consumer<Response<?, ?>> callback) {
         if (successor instanceof LocalProxyTransaction) {
             forwardToLocal((LocalProxyTransaction)successor, request, callback);
         } else if (successor instanceof RemoteProxyTransaction) {
@@ -588,11 +741,11 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
 
     abstract void doSeal();
 
-    abstract void doAbort();
-
     @GuardedBy("this")
     abstract void flushState(AbstractProxyTransaction successor);
 
+    abstract TransactionRequest<?> abortRequest();
+
     abstract TransactionRequest<?> commitRequest(boolean coordinated);
 
     /**
@@ -615,9 +768,10 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      *
      * @param request Request which needs to be forwarded
      * @param callback Callback to be invoked once the request completes
+     * @param enqueuedTicks Time stamp to use for enqueue time
      */
-    abstract void handleForwardedLocalRequest(AbstractLocalTransactionRequest<?> request,
-            @Nullable Consumer<Response<?, ?>> callback);
+    abstract void handleReplayedLocalRequest(AbstractLocalTransactionRequest<?> request,
+            @Nullable Consumer<Response<?, ?>> callback, long enqueuedTicks);
 
     /**
      * Invoked from {@link RemoteProxyTransaction} when it replays its successful requests to its successor.
@@ -627,9 +781,10 @@ abstract class AbstractProxyTransaction implements Identifiable<TransactionIdent
      *
      * @param request Request which needs to be forwarded
      * @param callback Callback to be invoked once the request completes
+     * @param enqueuedTicks Time stamp to use for enqueue time
      */
-    abstract void handleForwardedRemoteRequest(TransactionRequest<?> request,
-            @Nullable Consumer<Response<?, ?>> callback);
+    abstract void handleReplayedRemoteRequest(TransactionRequest<?> request,
+            @Nullable Consumer<Response<?, ?>> callback, long enqueuedTicks);
 
     @Override
     public final String toString() {