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.util.concurrent.AbstractFuture;
  12 import com.google.common.util.concurrent.AbstractListeningExecutorService;
  13 import com.google.common.util.concurrent.CheckedFuture;
  14 import com.google.common.util.concurrent.FutureCallback;
  15 import com.google.common.util.concurrent.Futures;
  16 import com.google.common.util.concurrent.ListenableFuture;
  17 import java.util.Collection;
  18 import java.util.Iterator;
  19 import java.util.List;
  20 import java.util.Map;
  21 import java.util.concurrent.Executor;
  22 import java.util.concurrent.ExecutorService;
  23 import java.util.concurrent.TimeUnit;
  24 import org.opendaylight.controller.cluster.databroker.AbstractDOMBroker;
  25 import org.opendaylight.controller.md.sal.common.api.data.LogicalDatastoreType;
  26 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
  27 import org.opendaylight.controller.md.sal.dom.api.DOMDataWriteTransaction;
  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  * ConcurrentDOMDataBroker commits transactions 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 AbstractDOMBroker {
  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             Collection<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 AsyncNotifyingSettableFuture clientSubmitFuture =
  80                 new AsyncNotifyingSettableFuture(clientFutureCallbackExecutor);
  81
  82         doCanCommit(clientSubmitFuture, transaction, cohorts);
  83
  84         return MappingCheckedFuture.create(clientSubmitFuture,
  85                 TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER);
  86     }
  87
  88     private void doCanCommit(final AsyncNotifyingSettableFuture clientSubmitFuture,
  89             final DOMDataWriteTransaction transaction,
  90             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
  91
  92         final long startTime = System.nanoTime();
  93
  94         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
  95
  96         // Not using Futures.allAsList here to avoid its internal overhead.
  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,
 102                             CAN_COMMIT, TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER,
 103                             new TransactionCommitFailedException(
 104                                             "Can Commit failed, no detailed cause available."));
 105                 } else {
 106                     if(!cohortIterator.hasNext()) {
 107                         // All cohorts completed successfully - we can move on to the preCommit phase
 108                         doPreCommit(startTime, clientSubmitFuture, transaction, cohorts);
 109                     } else {
 110                         ListenableFuture<Boolean> canCommitFuture = cohortIterator.next().canCommit();
 111                         Futures.addCallback(canCommitFuture, this, internalFutureCallbackExecutor);
 112                     }
 113                 }
 114             }
 115
 116             @Override
 117             public void onFailure(Throwable t) {
 118                 handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT,
 119                         TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER, t);
 120             }
 121         };
 122
 123         ListenableFuture<Boolean> canCommitFuture = cohortIterator.next().canCommit();
 124         Futures.addCallback(canCommitFuture, futureCallback, internalFutureCallbackExecutor);
 125     }
 126
 127     private void doPreCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 128             final DOMDataWriteTransaction transaction,
 129             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 130
 131         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 132
 133         // Not using Futures.allAsList here to avoid its internal overhead.
 134         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 135             @Override
 136             public void onSuccess(Void notUsed) {
 137                 if(!cohortIterator.hasNext()) {
 138                     // All cohorts completed successfully - we can move on to the commit phase
 139                     doCommit(startTime, clientSubmitFuture, transaction, cohorts);
 140                 } else {
 141                     ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 142                     Futures.addCallback(preCommitFuture, this, internalFutureCallbackExecutor);
 143                 }
 144             }
 145
 146             @Override
 147             public void onFailure(Throwable t) {
 148                 handleException(clientSubmitFuture, transaction, cohorts, PRE_COMMIT,
 149                         TransactionCommitFailedExceptionMapper.PRE_COMMIT_MAPPER, t);
 150             }
 151         };
 152
 153         ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 154         Futures.addCallback(preCommitFuture, futureCallback, internalFutureCallbackExecutor);
 155     }
 156
 157     private void doCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 158             final DOMDataWriteTransaction transaction,
 159             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 160
 161         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 162
 163         // Not using Futures.allAsList here to avoid its internal overhead.
 164         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 165             @Override
 166             public void onSuccess(Void notUsed) {
 167                 if(!cohortIterator.hasNext()) {
 168                     // All cohorts completed successfully - we're done.
 169                     commitStatsTracker.addDuration(System.nanoTime() - startTime);
 170
 171                     clientSubmitFuture.set();
 172                 } else {
 173                     ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 174                     Futures.addCallback(commitFuture, this, internalFutureCallbackExecutor);
 175                 }
 176             }
 177
 178             @Override
 179             public void onFailure(Throwable t) {
 180                 handleException(clientSubmitFuture, transaction, cohorts, COMMIT,
 181                         TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER, t);
 182             }
 183         };
 184
 185         ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 186         Futures.addCallback(commitFuture, futureCallback, internalFutureCallbackExecutor);
 187     }
 188
 189     private void handleException(final AsyncNotifyingSettableFuture clientSubmitFuture,
 190             final DOMDataWriteTransaction transaction,
 191             final Collection<DOMStoreThreePhaseCommitCohort> cohorts,
 192             final String phase, final TransactionCommitFailedExceptionMapper exMapper,
 193             final Throwable t) {
 194
 195         if(clientSubmitFuture.isDone()) {
 196             // We must have had failures from multiple cohorts.
 197             return;
 198         }
 199
 200         LOG.warn("Tx: {} Error during phase {}, starting Abort", transaction.getIdentifier(), phase, t);
 201         Exception e;
 202         if(t instanceof Exception) {
 203             e = (Exception)t;
 204         } else {
 205             e = new RuntimeException("Unexpected error occurred", t);
 206         }
 207
 208         final TransactionCommitFailedException clientException = exMapper.apply(e);
 209
 210         // Transaction failed - tell all cohorts to abort.
 211
 212         @SuppressWarnings("unchecked")
 213         ListenableFuture<Void>[] canCommitFutures = new ListenableFuture[cohorts.size()];
 214         int i = 0;
 215         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 216             canCommitFutures[i++] = cohort.abort();
 217         }
 218
 219         ListenableFuture<List<Void>> combinedFuture = Futures.allAsList(canCommitFutures);
 220         Futures.addCallback(combinedFuture, new FutureCallback<List<Void>>() {
 221             @Override
 222             public void onSuccess(List<Void> notUsed) {
 223                 // Propagate the original exception to the client.
 224                 clientSubmitFuture.setException(clientException);
 225             }
 226
 227             @Override
 228             public void onFailure(Throwable t) {
 229                 LOG.error("Tx: {} Error during Abort.", transaction.getIdentifier(), t);
 230
 231                 // Propagate the original exception as that is what caused the Tx to fail and is
 232                 // what's interesting to the client.
 233                 clientSubmitFuture.setException(clientException);
 234             }
 235         }, internalFutureCallbackExecutor);
 236     }
 237
 238     /**
 239      * A settable future that uses an {@link Executor} to execute listener callback Runnables,
 240      * registered via {@link #addListener}, asynchronously when this future completes. This is
 241      * done to guarantee listener executions are off-loaded onto another thread to avoid blocking
 242      * the thread that completed this future, as a common use case is to pass an executor that runs
 243      * tasks in the same thread as the caller (ie MoreExecutors#sameThreadExecutor)
 244      * to {@link #addListener}.
 245      *
 246      * FIXME: This class should probably be moved to yangtools common utils for re-usability and
 247      * unified with AsyncNotifyingListenableFutureTask.
 248      */
 249     private static class AsyncNotifyingSettableFuture extends AbstractFuture<Void> {
 250
 251         /**
 252          * ThreadLocal used to detect if the task completion thread is running the future listener Runnables.
 253          */
 254         private static final ThreadLocal<Boolean> ON_TASK_COMPLETION_THREAD_TL = new ThreadLocal<Boolean>();
 255
 256         private final ExecutorService listenerExecutor;
 257
 258         AsyncNotifyingSettableFuture(ExecutorService listenerExecutor) {
 259             this.listenerExecutor = listenerExecutor;
 260         }
 261
 262         @Override
 263         public void addListener(final Runnable listener, final Executor executor) {
 264             // Wrap the listener Runnable in a DelegatingRunnable. If the specified executor is one
 265             // that runs tasks in the same thread as the caller submitting the task
 266             // (e.g. {@link com.google.common.util.concurrent.MoreExecutors#sameThreadExecutor}) and
 267             // the listener is executed from the #set methods, then the DelegatingRunnable will detect
 268             // this via the ThreadLocal and submit the listener Runnable to the listenerExecutor.
 269             //
 270             // On the other hand, if this task is already complete, the call to ExecutionList#add in
 271             // superclass will execute the listener Runnable immediately and, since the ThreadLocal
 272             // won't be set, the DelegatingRunnable will run the listener Runnable inline.
 273             super.addListener(new DelegatingRunnable(listener, listenerExecutor), executor);
 274         }
 275
 276         boolean set() {
 277             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 278             try {
 279                 return super.set(null);
 280             } finally {
 281                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 282             }
 283         }
 284
 285         @Override
 286         protected boolean setException(Throwable throwable) {
 287             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 288             try {
 289                 return super.setException(throwable);
 290             } finally {
 291                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 292             }
 293         }
 294
 295         private static final class DelegatingRunnable implements Runnable {
 296             private final Runnable delegate;
 297             private final Executor executor;
 298
 299             DelegatingRunnable(final Runnable delegate, final Executor executor) {
 300                 this.delegate = Preconditions.checkNotNull(delegate);
 301                 this.executor = Preconditions.checkNotNull(executor);
 302             }
 303
 304             @Override
 305             public void run() {
 306                 if (ON_TASK_COMPLETION_THREAD_TL.get() != null) {
 307                     // We're running on the task completion thread so off-load to the executor.
 308                     LOG.trace("Submitting ListenenableFuture Runnable from thread {} to executor {}",
 309                             Thread.currentThread().getName(), executor);
 310                     executor.execute(delegate);
 311                 } else {
 312                     // We're not running on the task completion thread so run the delegate inline.
 313                     LOG.trace("Executing ListenenableFuture Runnable on this thread: {}",
 314                             Thread.currentThread().getName());
 315                     delegate.run();
 316                 }
 317             }
 318         }
 319     }
 320
 321     /**
 322      * A simple same-thread executor without the internal locking overhead that
 323      * MoreExecutors#sameThreadExecutor has. The #execute method is the only one of concern - we
 324      * don't shutdown the executor so the other methods irrelevant.
 325      */
 326     private static class SimpleSameThreadExecutor extends AbstractListeningExecutorService {
 327
 328         @Override
 329         public void execute(Runnable command) {
 330             command.run();
 331         }
 332
 333         @Override
 334         public boolean awaitTermination(long arg0, TimeUnit arg1) throws InterruptedException {
 335             return true;
 336         }
 337
 338         @Override
 339         public boolean isShutdown() {
 340             return false;
 341         }
 342
 343         @Override
 344         public boolean isTerminated() {
 345             return false;
 346         }
 347
 348         @Override
 349         public void shutdown() {
 350         }
 351
 352         @Override
 353         public List<Runnable> shutdownNow() {
 354             return null;
 355         }
 356     }
 357 }