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         if(cohorts.isEmpty()){
  80             return Futures.immediateCheckedFuture(null);
  81         }
  82
  83         final AsyncNotifyingSettableFuture clientSubmitFuture =
  84                 new AsyncNotifyingSettableFuture(clientFutureCallbackExecutor);
  85
  86         doCanCommit(clientSubmitFuture, transaction, cohorts);
  87
  88         return MappingCheckedFuture.create(clientSubmitFuture,
  89                 TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER);
  90     }
  91
  92     private void doCanCommit(final AsyncNotifyingSettableFuture clientSubmitFuture,
  93             final DOMDataWriteTransaction transaction,
  94             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
  95
  96         final long startTime = System.nanoTime();
  97
  98         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
  99
 100         // Not using Futures.allAsList here to avoid its internal overhead.
 101         FutureCallback<Boolean> futureCallback = new FutureCallback<Boolean>() {
 102             @Override
 103             public void onSuccess(Boolean result) {
 104                 if (result == null || !result) {
 105                     handleException(clientSubmitFuture, transaction, cohorts,
 106                             CAN_COMMIT, TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER,
 107                             new TransactionCommitFailedException(
 108                                             "Can Commit failed, no detailed cause available."));
 109                 } else {
 110                     if(!cohortIterator.hasNext()) {
 111                         // All cohorts completed successfully - we can move on to the preCommit phase
 112                         doPreCommit(startTime, clientSubmitFuture, transaction, cohorts);
 113                     } else {
 114                         ListenableFuture<Boolean> canCommitFuture = cohortIterator.next().canCommit();
 115                         Futures.addCallback(canCommitFuture, this, internalFutureCallbackExecutor);
 116                     }
 117                 }
 118             }
 119
 120             @Override
 121             public void onFailure(Throwable t) {
 122                 handleException(clientSubmitFuture, transaction, cohorts, CAN_COMMIT,
 123                         TransactionCommitFailedExceptionMapper.CAN_COMMIT_ERROR_MAPPER, t);
 124             }
 125         };
 126
 127         ListenableFuture<Boolean> canCommitFuture = cohortIterator.next().canCommit();
 128         Futures.addCallback(canCommitFuture, futureCallback, internalFutureCallbackExecutor);
 129     }
 130
 131     private void doPreCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 132             final DOMDataWriteTransaction transaction,
 133             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 134
 135         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 136
 137         // Not using Futures.allAsList here to avoid its internal overhead.
 138         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 139             @Override
 140             public void onSuccess(Void notUsed) {
 141                 if(!cohortIterator.hasNext()) {
 142                     // All cohorts completed successfully - we can move on to the commit phase
 143                     doCommit(startTime, clientSubmitFuture, transaction, cohorts);
 144                 } else {
 145                     ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 146                     Futures.addCallback(preCommitFuture, this, internalFutureCallbackExecutor);
 147                 }
 148             }
 149
 150             @Override
 151             public void onFailure(Throwable t) {
 152                 handleException(clientSubmitFuture, transaction, cohorts, PRE_COMMIT,
 153                         TransactionCommitFailedExceptionMapper.PRE_COMMIT_MAPPER, t);
 154             }
 155         };
 156
 157         ListenableFuture<Void> preCommitFuture = cohortIterator.next().preCommit();
 158         Futures.addCallback(preCommitFuture, futureCallback, internalFutureCallbackExecutor);
 159     }
 160
 161     private void doCommit(final long startTime, final AsyncNotifyingSettableFuture clientSubmitFuture,
 162             final DOMDataWriteTransaction transaction,
 163             final Collection<DOMStoreThreePhaseCommitCohort> cohorts) {
 164
 165         final Iterator<DOMStoreThreePhaseCommitCohort> cohortIterator = cohorts.iterator();
 166
 167         // Not using Futures.allAsList here to avoid its internal overhead.
 168         FutureCallback<Void> futureCallback = new FutureCallback<Void>() {
 169             @Override
 170             public void onSuccess(Void notUsed) {
 171                 if(!cohortIterator.hasNext()) {
 172                     // All cohorts completed successfully - we're done.
 173                     commitStatsTracker.addDuration(System.nanoTime() - startTime);
 174
 175                     clientSubmitFuture.set();
 176                 } else {
 177                     ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 178                     Futures.addCallback(commitFuture, this, internalFutureCallbackExecutor);
 179                 }
 180             }
 181
 182             @Override
 183             public void onFailure(Throwable t) {
 184                 handleException(clientSubmitFuture, transaction, cohorts, COMMIT,
 185                         TransactionCommitFailedExceptionMapper.COMMIT_ERROR_MAPPER, t);
 186             }
 187         };
 188
 189         ListenableFuture<Void> commitFuture = cohortIterator.next().commit();
 190         Futures.addCallback(commitFuture, futureCallback, internalFutureCallbackExecutor);
 191     }
 192
 193     private void handleException(final AsyncNotifyingSettableFuture clientSubmitFuture,
 194             final DOMDataWriteTransaction transaction,
 195             final Collection<DOMStoreThreePhaseCommitCohort> cohorts,
 196             final String phase, final TransactionCommitFailedExceptionMapper exMapper,
 197             final Throwable t) {
 198
 199         if(clientSubmitFuture.isDone()) {
 200             // We must have had failures from multiple cohorts.
 201             return;
 202         }
 203
 204         LOG.warn("Tx: {} Error during phase {}, starting Abort", transaction.getIdentifier(), phase, t);
 205         Exception e;
 206         if(t instanceof Exception) {
 207             e = (Exception)t;
 208         } else {
 209             e = new RuntimeException("Unexpected error occurred", t);
 210         }
 211
 212         final TransactionCommitFailedException clientException = exMapper.apply(e);
 213
 214         // Transaction failed - tell all cohorts to abort.
 215
 216         @SuppressWarnings("unchecked")
 217         ListenableFuture<Void>[] canCommitFutures = new ListenableFuture[cohorts.size()];
 218         int i = 0;
 219         for(DOMStoreThreePhaseCommitCohort cohort: cohorts) {
 220             canCommitFutures[i++] = cohort.abort();
 221         }
 222
 223         ListenableFuture<List<Void>> combinedFuture = Futures.allAsList(canCommitFutures);
 224         Futures.addCallback(combinedFuture, new FutureCallback<List<Void>>() {
 225             @Override
 226             public void onSuccess(List<Void> notUsed) {
 227                 // Propagate the original exception to the client.
 228                 clientSubmitFuture.setException(clientException);
 229             }
 230
 231             @Override
 232             public void onFailure(Throwable t) {
 233                 LOG.error("Tx: {} Error during Abort.", transaction.getIdentifier(), t);
 234
 235                 // Propagate the original exception as that is what caused the Tx to fail and is
 236                 // what's interesting to the client.
 237                 clientSubmitFuture.setException(clientException);
 238             }
 239         }, internalFutureCallbackExecutor);
 240     }
 241
 242     /**
 243      * A settable future that uses an {@link Executor} to execute listener callback Runnables,
 244      * registered via {@link #addListener}, asynchronously when this future completes. This is
 245      * done to guarantee listener executions are off-loaded onto another thread to avoid blocking
 246      * the thread that completed this future, as a common use case is to pass an executor that runs
 247      * tasks in the same thread as the caller (ie MoreExecutors#sameThreadExecutor)
 248      * to {@link #addListener}.
 249      *
 250      * FIXME: This class should probably be moved to yangtools common utils for re-usability and
 251      * unified with AsyncNotifyingListenableFutureTask.
 252      */
 253     private static class AsyncNotifyingSettableFuture extends AbstractFuture<Void> {
 254
 255         /**
 256          * ThreadLocal used to detect if the task completion thread is running the future listener Runnables.
 257          */
 258         private static final ThreadLocal<Boolean> ON_TASK_COMPLETION_THREAD_TL = new ThreadLocal<Boolean>();
 259
 260         private final ExecutorService listenerExecutor;
 261
 262         AsyncNotifyingSettableFuture(ExecutorService listenerExecutor) {
 263             this.listenerExecutor = listenerExecutor;
 264         }
 265
 266         @Override
 267         public void addListener(final Runnable listener, final Executor executor) {
 268             // Wrap the listener Runnable in a DelegatingRunnable. If the specified executor is one
 269             // that runs tasks in the same thread as the caller submitting the task
 270             // (e.g. {@link com.google.common.util.concurrent.MoreExecutors#sameThreadExecutor}) and
 271             // the listener is executed from the #set methods, then the DelegatingRunnable will detect
 272             // this via the ThreadLocal and submit the listener Runnable to the listenerExecutor.
 273             //
 274             // On the other hand, if this task is already complete, the call to ExecutionList#add in
 275             // superclass will execute the listener Runnable immediately and, since the ThreadLocal
 276             // won't be set, the DelegatingRunnable will run the listener Runnable inline.
 277             super.addListener(new DelegatingRunnable(listener, listenerExecutor), executor);
 278         }
 279
 280         boolean set() {
 281             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 282             try {
 283                 return super.set(null);
 284             } finally {
 285                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 286             }
 287         }
 288
 289         @Override
 290         protected boolean setException(Throwable throwable) {
 291             ON_TASK_COMPLETION_THREAD_TL.set(Boolean.TRUE);
 292             try {
 293                 return super.setException(throwable);
 294             } finally {
 295                 ON_TASK_COMPLETION_THREAD_TL.set(null);
 296             }
 297         }
 298
 299         private static final class DelegatingRunnable implements Runnable {
 300             private final Runnable delegate;
 301             private final Executor executor;
 302
 303             DelegatingRunnable(final Runnable delegate, final Executor executor) {
 304                 this.delegate = Preconditions.checkNotNull(delegate);
 305                 this.executor = Preconditions.checkNotNull(executor);
 306             }
 307
 308             @Override
 309             public void run() {
 310                 if (ON_TASK_COMPLETION_THREAD_TL.get() != null) {
 311                     // We're running on the task completion thread so off-load to the executor.
 312                     LOG.trace("Submitting ListenenableFuture Runnable from thread {} to executor {}",
 313                             Thread.currentThread().getName(), executor);
 314                     executor.execute(delegate);
 315                 } else {
 316                     // We're not running on the task completion thread so run the delegate inline.
 317                     LOG.trace("Executing ListenenableFuture Runnable on this thread: {}",
 318                             Thread.currentThread().getName());
 319                     delegate.run();
 320                 }
 321             }
 322         }
 323     }
 324
 325     /**
 326      * A simple same-thread executor without the internal locking overhead that
 327      * MoreExecutors#sameThreadExecutor has. The #execute method is the only one of concern - we
 328      * don't shutdown the executor so the other methods irrelevant.
 329      */
 330     private static class SimpleSameThreadExecutor extends AbstractListeningExecutorService {
 331
 332         @Override
 333         public void execute(Runnable command) {
 334             command.run();
 335         }
 336
 337         @Override
 338         public boolean awaitTermination(long arg0, TimeUnit arg1) throws InterruptedException {
 339             return true;
 340         }
 341
 342         @Override
 343         public boolean isShutdown() {
 344             return false;
 345         }
 346
 347         @Override
 348         public boolean isTerminated() {
 349             return false;
 350         }
 351
 352         @Override
 353         public void shutdown() {
 354         }
 355
 356         @Override
 357         public List<Runnable> shutdownNow() {
 358             return null;
 359         }
 360     }
 361 }