opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ConcurrentDOMDataBroker.java

   1 /*
   2  * Copyright (c) 2014 Brocade Communications Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.datastore;
   9
  10 import com.google.common.base.Preconditions;
  11 import com.google.common.collect.Iterables;
  12 import com.google.common.util.concurrent.AbstractFuture;
  13 import com.google.common.util.concurrent.AbstractListeningExecutorService;
  14 import com.google.common.util.concurrent.CheckedFuture;
  15 import com.google.common.util.concurrent.FutureCallback;
  16 import com.google.common.util.concurrent.Futures;
  17 import com.google.common.util.concurrent.ListenableFuture;
  18 import java.util.List;
  19 import java.util.Map;
  20 import java.util.concurrent.Executor;
  21 import java.util.concurrent.ExecutorService;
  22 import java.util.concurrent.TimeUnit;
  23 import java.util.concurrent.atomic.AtomicInteger;
  24 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  25 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  26 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  27 import org.opendaylight.controller.md.sal.dom.broker.impl.AbstractDOMDataBroker;
  28 import org.opendaylight.controller.md.sal.dom.broker.impl.TransactionCommitFailedExceptionMapper;
  29 import org.opendaylight.controller.sal.core.spi.data.DOMStore;
  30 import org.opendaylight.controller.sal.core.spi.data.DOMStoreThreePhaseCommitCohort;
  31 import org.opendaylight.yangtools.util.DurationStatisticsTracker;
  32 import org.opendaylight.yangtools.util.concurrent.MappingCheckedFuture;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 /**
  37  * Implementation of DOMDataCommitExecutor that coordinates transaction commits concurrently. The 3
  38  * commit phases (canCommit, preCommit, and commit) are performed serially and non-blocking
  39  * (ie async) per transaction but multiple transaction commits can run concurrent.
  40  *
  41  * @author Thomas Pantelis
  42  */
  43 public class ConcurrentDOMDataBroker extends AbstractDOMDataBroker {
  44     private static final Logger LOG = LoggerFactory.getLogger(ConcurrentDOMDataBroker.class);
  45     private static final String CAN_COMMIT = "CAN_COMMIT";
  46     private static final String PRE_COMMIT = "PRE_COMMIT";
  47     private static final String COMMIT = "COMMIT";
  48
  49     private final DurationStatisticsTracker commitStatsTracker = DurationStatisticsTracker.createConcurrent();
  50
  51     /**
  52      * This executor is used to execute Future listener callback Runnables async.
  53      */
  54     private final ExecutorService clientFutureCallbackExecutor;
  55
  56     /**
  57      * This executor is re-used internally in calls to Futures#addCallback to avoid the overhead
  58      * of Futures#addCallback creating a MoreExecutors#sameThreadExecutor for each call.
  59      */
  60     private final ExecutorService internalFutureCallbackExecutor = new SimpleSameThreadExecutor();
  61
  62     public ConcurrentDOMDataBroker(final Map<LogicalDatastoreType, DOMStore> datastores, ExecutorService listenableFutureExecutor) {
  63         super(datastores);
  64         this.clientFutureCallbackExecutor = Preconditions.checkNotNull(listenableFutureExecutor);
  65     }
  66
  67     public DurationStatisticsTracker getCommitStatsTracker() {
  68         return commitStatsTracker;
  69     }
  70
  71     @Override
  72     public CheckedFuture<Void, TransactionCommitFailedException> submit(DOMDataWriteTransaction transaction,
  73             Iterable<DOMStoreThreePhaseCommitCohort> cohorts) {
  74
  75         Preconditions.checkArgument(transaction != null, "Transaction must not be null.");
  76         Preconditions.checkArgument(cohorts != null, "Cohorts must not be null.");
  77         LOG.debug("Tx: {} is submitted for execution.", transaction.getIdentifier());
  78
  79         final int cohortSize = Iterables.size(cohorts);
  80         final AsyncNotifyingSettableFuture clientSubmitFuture =
  81                 new AsyncNotifyingSettableFuture(clientFutureCallbackExecutor);
  82
  83         doCanCommit(clientSubmitFuture, transaction, cohorts, cohortSize);
  84
  85         return MappingCheckedFuture.create(clientSubmitFuture,
  86                 TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER);
  87     }
  88
  89     private void doCanCommit(final AsyncNotifyingSettableFuture clientSubmitFuture,
  90             final DOMDataWriteTransaction transaction,
  91             final Iterable<DOMStoreThreePhaseCommitCohort> cohorts, final int cohortSize) {
  92
  93         final long startTime = System.nanoTime();
  94
  95         // Not using Futures.allAsList here to avoid its internal overhead.
  96         final AtomicInteger remaining = new AtomicInteger(cohortSize);
  97         FutureCallback<Boolean> futureCallback = new FutureCallback<Boolean>() {
  98             @Override
  99             public void onSuccess(Boolean result) {
 100                 if (result == null || !result) {
 101                     handleException(clientSubmitFuture, transaction, cohorts, cohortSize,
 102                             CAN_COMMIT, TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER,
 103                             new TransactionCommitFailedException(
 104                                             "Can Commit failed, no detailed cause available."));
 105                 } else {
 106                     if(remaining.decrementAndGet() == 0) {
 107                         // All cohorts completed successfully - we can move on to the preCommit phase
 108                         doPreCommit(startTime, clientSubmitFuture, transaction, cohorts, cohortSize);
 109                     }
 110                 }
 111             }
 112
 113             @Override
 114             public void onFailure(Throwable t) {
 115                 handleException(clientSubmitFuture, transaction, cohorts, cohortSize, CAN_COMMIT,
 116                         TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER, t);
 117             }
 118         };
 119
 120         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 121             ListenableFuture<Boolean> canCommitFuture = cohort.canCommit();
 122             Futures.addCallback(canCommitFuture, futureCallback, internalFutureCallbackExecutor);
 123         }
 124     }
 125
 126     private void doPreCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 127             final DOMDataWriteTransaction transaction,
 128             final Iterable<DOMStoreThreePhaseCommitCohort> cohorts, final int cohortSize) {
 129
 130         // Not using Futures.allAsList here to avoid its internal overhead.
 131         final AtomicInteger remaining = new AtomicInteger(cohortSize);
 132         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 133             @Override
 134             public void onSuccess(Void notUsed) {
 135                 if(remaining.decrementAndGet() == 0) {
 136                     // All cohorts completed successfully - we can move on to the commit phase
 137                     doCommit(startTime, clientSubmitFuture, transaction, cohorts, cohortSize);
 138                 }
 139             }
 140
 141             @Override
 142             public void onFailure(Throwable t) {
 143                 handleException(clientSubmitFuture, transaction, cohorts, cohortSize, PRE_COMMIT,
 144                         TransactionCommitFailedExceptionMapper.PRE_COMMIT_MAPPER, t);
 145             }
 146         };
 147
 148         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 149             ListenableFuture<Void> preCommitFuture = cohort.preCommit();
 150             Futures.addCallback(preCommitFuture, futureCallback, internalFutureCallbackExecutor);
 151         }
 152     }
 153
 154     private void doCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 155             final DOMDataWriteTransaction transaction,
 156             final Iterable<DOMStoreThreePhaseCommitCohort> cohorts, final int cohortSize) {
 157
 158         // Not using Futures.allAsList here to avoid its internal overhead.
 159         final AtomicInteger remaining = new AtomicInteger(cohortSize);
 160         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 161             @Override
 162             public void onSuccess(Void notUsed) {
 163                 if(remaining.decrementAndGet() == 0) {
 164                     // All cohorts completed successfully - we're done.
 165                     commitStatsTracker.addDuration(System.nanoTime() - startTime);
 166
 167                     clientSubmitFuture.set();
 168                 }
 169             }
 170
 171             @Override
 172             public void onFailure(Throwable t) {
 173                 handleException(clientSubmitFuture, transaction, cohorts, cohortSize, COMMIT,
 174                         TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER, t);
 175             }
 176         };
 177
 178         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 179             ListenableFuture<Void> commitFuture = cohort.commit();
 180             Futures.addCallback(commitFuture, futureCallback, internalFutureCallbackExecutor);
 181         }
 182     }
 183
 184     private void handleException(final AsyncNotifyingSettableFuture clientSubmitFuture,
 185             final DOMDataWriteTransaction transaction,
 186             final Iterable<DOMStoreThreePhaseCommitCohort> cohorts, int cohortSize,
 187             final String phase, final TransactionCommitFailedExceptionMapper exMapper,
 188             final Throwable t) {
 189
 190         if(clientSubmitFuture.isDone()) {
 191             // We must have had failures from multiple cohorts.
 192             return;
 193         }
 194
 195         LOG.warn("Tx: {} Error during phase {}, starting Abort", transaction.getIdentifier(), phase, t);
 196         Exception e;
 197         if(t instanceof Exception) {
 198             e = (Exception)t;
 199         } else {
 200             e = new RuntimeException("Unexpected error occurred", t);
 201         }
 202
 203         final TransactionCommitFailedException clientException = exMapper.apply(e);
 204
 205         // Transaction failed - tell all cohorts to abort.
 206
 207         @SuppressWarnings("unchecked")
 208         ListenableFuture<Void>[] canCommitFutures = new ListenableFuture[cohortSize];
 209         int i = 0;
 210         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 211             canCommitFutures[i++] = cohort.abort();
 212         }
 213
 214         ListenableFuture<List<Void>> combinedFuture = Futures.allAsList(canCommitFutures);
 215         Futures.addCallback(combinedFuture, new FutureCallback<List<Void>>() {
 216             @Override
 217             public void onSuccess(List<Void> notUsed) {
 218                 // Propagate the original exception to the client.
 219                 clientSubmitFuture.setException(clientException);
 220             }
 221
 222             @Override
 223             public void onFailure(Throwable t) {
 224                 LOG.error("Tx: {} Error during Abort.", transaction.getIdentifier(), t);
 225
 226                 // Propagate the original exception as that is what caused the Tx to fail and is
 227                 // what's interesting to the client.
 228                 clientSubmitFuture.setException(clientException);
 229             }
 230         }, internalFutureCallbackExecutor);
 231     }
 232
 233     /**
 234      * A settable future that uses an {@link Executor} to execute listener callback Runnables,
 235      * registered via {@link #addListener}, asynchronously when this future completes. This is
 236      * done to guarantee listener executions are off-loaded onto another thread to avoid blocking
 237      * the thread that completed this future, as a common use case is to pass an executor that runs
 238      * tasks in the same thread as the caller (ie MoreExecutors#sameThreadExecutor)
 239      * to {@link #addListener}.
 240      *
 241      * FIXME: This class should probably be moved to yangtools common utils for re-usability and
 242      * unified with AsyncNotifyingListenableFutureTask.
 243      */
 244     private static class AsyncNotifyingSettableFuture extends AbstractFuture<Void> {
 245
 246         /**
 247          * ThreadLocal used to detect if the task completion thread is running the future listener Runnables.
 248          */
 249         private static final ThreadLocal<Boolean> ON_TASK_COMPLETION_THREAD_TL = new ThreadLocal<Boolean>();
 250
 251         private final ExecutorService listenerExecutor;
 252
 253         AsyncNotifyingSettableFuture(ExecutorService listenerExecutor) {
 254             this.listenerExecutor = listenerExecutor;
 255         }
 256
 257         @Override
 258         public void addListener(final Runnable listener, final Executor executor) {
 259             // Wrap the listener Runnable in a DelegatingRunnable. If the specified executor is one
 260             // that runs tasks in the same thread as the caller submitting the task
 261             // (e.g. {@link com.google.common.util.concurrent.MoreExecutors#sameThreadExecutor}) and
 262             // the listener is executed from the #set methods, then the DelegatingRunnable will detect
 263             // this via the ThreadLocal and submit the listener Runnable to the listenerExecutor.
 264             //
 265             // On the other hand, if this task is already complete, the call to ExecutionList#add in
 266             // superclass will execute the listener Runnable immediately and, since the ThreadLocal
 267             // won't be set, the DelegatingRunnable will run the listener Runnable inline.
 268             super.addListener(new DelegatingRunnable(listener, listenerExecutor), executor);
 269         }
 270
 271         boolean set() {
 272             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 273             try {
 274                 return super.set(null);
 275             } finally {
 276                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 277             }
 278         }
 279
 280         @Override
 281         protected boolean setException(Throwable throwable) {
 282             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 283             try {
 284                 return super.setException(throwable);
 285             } finally {
 286                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 287             }
 288         }
 289
 290         private static final class DelegatingRunnable implements Runnable {
 291             private final Runnable delegate;
 292             private final Executor executor;
 293
 294             DelegatingRunnable(final Runnable delegate, final Executor executor) {
 295                 this.delegate = Preconditions.checkNotNull(delegate);
 296                 this.executor = Preconditions.checkNotNull(executor);
 297             }
 298
 299             @Override
 300             public void run() {
 301                 if (ON_TASK_COMPLETION_THREAD_TL.get() != null) {
 302                     // We're running on the task completion thread so off-load to the executor.
 303                     LOG.trace("Submitting ListenenableFuture Runnable from thread {} to executor {}",
 304                             Thread.currentThread().getName(), executor);
 305                     executor.execute(delegate);
 306                 } else {
 307                     // We're not running on the task completion thread so run the delegate inline.
 308                     LOG.trace("Executing ListenenableFuture Runnable on this thread: {}",
 309                             Thread.currentThread().getName());
 310                     delegate.run();
 311                 }
 312             }
 313         }
 314     }
 315
 316     /**
 317      * A simple same-thread executor without the internal locking overhead that
 318      * MoreExecutors#sameThreadExecutor has. The #execute method is the only one of concern - we
 319      * don't shutdown the executor so the other methods irrelevant.
 320      */
 321     private static class SimpleSameThreadExecutor extends AbstractListeningExecutorService {
 322
 323         @Override
 324         public void execute(Runnable command) {
 325             command.run();
 326         }
 327
 328         @Override
 329         public boolean awaitTermination(long arg0, TimeUnit arg1) throws InterruptedException {
 330             return true;
 331         }
 332
 333         @Override
 334         public boolean isShutdown() {
 335             return false;
 336         }
 337
 338         @Override
 339         public boolean isTerminated() {
 340             return false;
 341         }
 342
 343         @Override
 344         public void shutdown() {
 345         }
 346
 347         @Override
 348         public List<Runnable> shutdownNow() {
 349             return null;
 350         }
 351     }
 352 }