0dd50d479068d0b92f1e601352b9b91577a13c01
[controller.git] / opendaylight / md-sal / sal-distributed-datastore / src / main / java / org / opendaylight / controller / cluster / datastore / ShardCommitCoordinator.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 akka.actor.ActorRef;
11 import akka.actor.Status.Failure;
12 import akka.serialization.Serialization;
13 import com.google.common.annotations.VisibleForTesting;
14 import com.google.common.base.Preconditions;
15 import com.google.common.primitives.UnsignedLong;
16 import com.google.common.util.concurrent.FutureCallback;
17 import java.util.ArrayDeque;
18 import java.util.ArrayList;
19 import java.util.Collection;
20 import java.util.Collections;
21 import java.util.Deque;
22 import java.util.HashMap;
23 import java.util.Iterator;
24 import java.util.LinkedList;
25 import java.util.Map;
26 import javax.annotation.Nonnull;
27 import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier;
28 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
29 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
30 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
31 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
32 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
33 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
34 import org.opendaylight.controller.cluster.datastore.messages.CommitTransactionReply;
35 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
36 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
37 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
38 import org.opendaylight.controller.cluster.datastore.messages.VersionedExternalizableMessage;
39 import org.opendaylight.controller.cluster.datastore.utils.AbstractBatchedModificationsCursor;
40 import org.opendaylight.yangtools.concepts.Identifier;
41 import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate;
42 import org.slf4j.Logger;
43
44 /**
45  * Coordinates commits for a shard ensuring only one concurrent 3-phase commit.
46  *
47  * @author Thomas Pantelis
48  */
49 final class ShardCommitCoordinator {
50
51     // Interface hook for unit tests to replace or decorate the ShardDataTreeCohorts.
52     @VisibleForTesting
53     public interface CohortDecorator {
54         ShardDataTreeCohort decorate(Identifier transactionID, ShardDataTreeCohort actual);
55     }
56
57     private final Map<Identifier, CohortEntry> cohortCache = new HashMap<>();
58
59     private final ShardDataTree dataTree;
60
61     private final Logger log;
62
63     private final String name;
64
65     // This is a hook for unit tests to replace or decorate the ShardDataTreeCohorts.
66     @VisibleForTesting
67     private CohortDecorator cohortDecorator;
68
69     private ReadyTransactionReply readyTransactionReply;
70
71     ShardCommitCoordinator(final ShardDataTree dataTree, final Logger log, final String name) {
72         this.log = log;
73         this.name = name;
74         this.dataTree = Preconditions.checkNotNull(dataTree);
75     }
76
77     int getCohortCacheSize() {
78         return cohortCache.size();
79     }
80
81     private String persistenceId() {
82         return dataTree.logContext();
83     }
84
85     private ReadyTransactionReply readyTransactionReply(final ActorRef cohort) {
86         if (readyTransactionReply == null) {
87             readyTransactionReply = new ReadyTransactionReply(Serialization.serializedActorPath(cohort));
88         }
89
90         return readyTransactionReply;
91     }
92
93     /**
94      * This method is called to ready a transaction that was prepared by ShardTransaction actor. It caches
95      * the prepared cohort entry for the given transactions ID in preparation for the subsequent 3-phase commit.
96      *
97      * @param ready the ForwardedReadyTransaction message to process
98      * @param sender the sender of the message
99      * @param shard the transaction's shard actor
100      */
101     void handleForwardedReadyTransaction(final ForwardedReadyTransaction ready, final ActorRef sender,
102             final Shard shard) {
103         log.debug("{}: Readying transaction {}, client version {}", name,
104                 ready.getTransactionId(), ready.getTxnClientVersion());
105
106         final ShardDataTreeCohort cohort = ready.getTransaction().ready(ready.getParticipatingShardNames());
107         final CohortEntry cohortEntry = CohortEntry.createReady(cohort, ready.getTxnClientVersion());
108         cohortCache.put(cohortEntry.getTransactionId(), cohortEntry);
109
110         if (ready.isDoImmediateCommit()) {
111             cohortEntry.setDoImmediateCommit(true);
112             cohortEntry.setReplySender(sender);
113             cohortEntry.setShard(shard);
114             handleCanCommit(cohortEntry);
115         } else {
116             // The caller does not want immediate commit - the 3-phase commit will be coordinated by the
117             // front-end so send back a ReadyTransactionReply with our actor path.
118             sender.tell(readyTransactionReply(shard.self()), shard.self());
119         }
120     }
121
122     /**
123      * This method handles a BatchedModifications message for a transaction being prepared directly on the
124      * Shard actor instead of via a ShardTransaction actor. If there's no currently cached
125      * DOMStoreWriteTransaction, one is created. The batched modifications are applied to the write Tx. If
126      * the BatchedModifications is ready to commit then a DOMStoreThreePhaseCommitCohort is created.
127      *
128      * @param batched the BatchedModifications message to process
129      * @param sender the sender of the message
130      */
131     void handleBatchedModifications(final BatchedModifications batched, final ActorRef sender, final Shard shard) {
132         CohortEntry cohortEntry = cohortCache.get(batched.getTransactionId());
133         if (cohortEntry == null) {
134             cohortEntry = CohortEntry.createOpen(dataTree.newReadWriteTransaction(batched.getTransactionId()),
135                 batched.getVersion());
136             cohortCache.put(cohortEntry.getTransactionId(), cohortEntry);
137         }
138
139         if (log.isDebugEnabled()) {
140             log.debug("{}: Applying {} batched modifications for Tx {}", name,
141                     batched.getModifications().size(), batched.getTransactionId());
142         }
143
144         cohortEntry.applyModifications(batched.getModifications());
145
146         if (batched.isReady()) {
147             if (cohortEntry.getLastBatchedModificationsException() != null) {
148                 cohortCache.remove(cohortEntry.getTransactionId());
149                 throw cohortEntry.getLastBatchedModificationsException();
150             }
151
152             if (cohortEntry.getTotalBatchedModificationsReceived() != batched.getTotalMessagesSent()) {
153                 cohortCache.remove(cohortEntry.getTransactionId());
154                 throw new IllegalStateException(String.format(
155                         "The total number of batched messages received %d does not match the number sent %d",
156                         cohortEntry.getTotalBatchedModificationsReceived(), batched.getTotalMessagesSent()));
157             }
158
159             if (log.isDebugEnabled()) {
160                 log.debug("{}: Readying Tx {}, client version {}", name,
161                         batched.getTransactionId(), batched.getVersion());
162             }
163
164             cohortEntry.setDoImmediateCommit(batched.isDoCommitOnReady());
165             cohortEntry.ready(batched.getParticipatingShardNames(), cohortDecorator);
166
167             if (batched.isDoCommitOnReady()) {
168                 cohortEntry.setReplySender(sender);
169                 cohortEntry.setShard(shard);
170                 handleCanCommit(cohortEntry);
171             } else {
172                 sender.tell(readyTransactionReply(shard.self()), shard.self());
173             }
174         } else {
175             sender.tell(new BatchedModificationsReply(batched.getModifications().size()), shard.self());
176         }
177     }
178
179     /**
180      * This method handles {@link ReadyLocalTransaction} message. All transaction modifications have
181      * been prepared beforehand by the sender and we just need to drive them through into the
182      * dataTree.
183      *
184      * @param message the ReadyLocalTransaction message to process
185      * @param sender the sender of the message
186      * @param shard the transaction's shard actor
187      */
188     void handleReadyLocalTransaction(final ReadyLocalTransaction message, final ActorRef sender, final Shard shard) {
189         final TransactionIdentifier txId = message.getTransactionId();
190         final ShardDataTreeCohort cohort = dataTree.newReadyCohort(txId, message.getModification(),
191                 message.getParticipatingShardNames());
192         final CohortEntry cohortEntry = CohortEntry.createReady(cohort, DataStoreVersions.CURRENT_VERSION);
193         cohortCache.put(cohortEntry.getTransactionId(), cohortEntry);
194         cohortEntry.setDoImmediateCommit(message.isDoCommitOnReady());
195
196         log.debug("{}: Applying local modifications for Tx {}", name, txId);
197
198         if (message.isDoCommitOnReady()) {
199             cohortEntry.setReplySender(sender);
200             cohortEntry.setShard(shard);
201             handleCanCommit(cohortEntry);
202         } else {
203             sender.tell(readyTransactionReply(shard.self()), shard.self());
204         }
205     }
206
207     Collection<BatchedModifications> createForwardedBatchedModifications(final BatchedModifications from,
208             final int maxModificationsPerBatch) {
209         CohortEntry cohortEntry = cohortCache.remove(from.getTransactionId());
210         if (cohortEntry == null || cohortEntry.getTransaction() == null) {
211             return Collections.singletonList(from);
212         }
213
214         cohortEntry.applyModifications(from.getModifications());
215
216         final LinkedList<BatchedModifications> newModifications = new LinkedList<>();
217         cohortEntry.getTransaction().getSnapshot().applyToCursor(new AbstractBatchedModificationsCursor() {
218             @Override
219             protected BatchedModifications getModifications() {
220                 if (newModifications.isEmpty()
221                         || newModifications.getLast().getModifications().size() >= maxModificationsPerBatch) {
222                     newModifications.add(new BatchedModifications(from.getTransactionId(), from.getVersion()));
223                 }
224
225                 return newModifications.getLast();
226             }
227         });
228
229         BatchedModifications last = newModifications.getLast();
230         last.setDoCommitOnReady(from.isDoCommitOnReady());
231         if (from.isReady()) {
232             last.setReady(from.getParticipatingShardNames());
233         }
234         last.setTotalMessagesSent(newModifications.size());
235         return newModifications;
236     }
237
238     private void handleCanCommit(final CohortEntry cohortEntry) {
239         cohortEntry.canCommit(new FutureCallback<Void>() {
240             @Override
241             public void onSuccess(final Void result) {
242                 log.debug("{}: canCommit for {}: success", name, cohortEntry.getTransactionId());
243
244                 if (cohortEntry.isDoImmediateCommit()) {
245                     doCommit(cohortEntry);
246                 } else {
247                     cohortEntry.getReplySender().tell(
248                         CanCommitTransactionReply.yes(cohortEntry.getClientVersion()).toSerializable(),
249                         cohortEntry.getShard().self());
250                 }
251             }
252
253             @Override
254             public void onFailure(final Throwable failure) {
255                 log.debug("{}: An exception occurred during canCommit for {}: {}", name,
256                         cohortEntry.getTransactionId(), failure);
257
258                 cohortCache.remove(cohortEntry.getTransactionId());
259                 cohortEntry.getReplySender().tell(new Failure(failure), cohortEntry.getShard().self());
260             }
261         });
262     }
263
264     /**
265      * This method handles the canCommit phase for a transaction.
266      *
267      * @param transactionID the ID of the transaction to canCommit
268      * @param sender the actor to which to send the response
269      * @param shard the transaction's shard actor
270      */
271     void handleCanCommit(final Identifier transactionID, final ActorRef sender, final Shard shard) {
272         // Lookup the cohort entry that was cached previously (or should have been) by
273         // transactionReady (via the ForwardedReadyTransaction message).
274         final CohortEntry cohortEntry = cohortCache.get(transactionID);
275         if (cohortEntry == null) {
276             // Either canCommit was invoked before ready (shouldn't happen) or a long time passed
277             // between canCommit and ready and the entry was expired from the cache or it was aborted.
278             IllegalStateException ex = new IllegalStateException(
279                     String.format("%s: Cannot canCommit transaction %s - no cohort entry found", name, transactionID));
280             log.error(ex.getMessage());
281             sender.tell(new Failure(ex), shard.self());
282             return;
283         }
284
285         cohortEntry.setReplySender(sender);
286         cohortEntry.setShard(shard);
287
288         handleCanCommit(cohortEntry);
289     }
290
291     void doCommit(final CohortEntry cohortEntry) {
292         log.debug("{}: Committing transaction {}", name, cohortEntry.getTransactionId());
293
294         // We perform the preCommit phase here atomically with the commit phase. This is an
295         // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
296         // coordination of preCommit across shards in case of failure but preCommit should not
297         // normally fail since we ensure only one concurrent 3-phase commit.
298         cohortEntry.preCommit(new FutureCallback<DataTreeCandidate>() {
299             @Override
300             public void onSuccess(final DataTreeCandidate candidate) {
301                 finishCommit(cohortEntry.getReplySender(), cohortEntry);
302             }
303
304             @Override
305             public void onFailure(final Throwable failure) {
306                 log.error("{} An exception occurred while preCommitting transaction {}", name,
307                         cohortEntry.getTransactionId(), failure);
308
309                 cohortCache.remove(cohortEntry.getTransactionId());
310                 cohortEntry.getReplySender().tell(new Failure(failure), cohortEntry.getShard().self());
311             }
312         });
313     }
314
315     void finishCommit(@Nonnull final ActorRef sender, @Nonnull final CohortEntry cohortEntry) {
316         log.debug("{}: Finishing commit for transaction {}", persistenceId(), cohortEntry.getTransactionId());
317
318         cohortEntry.commit(new FutureCallback<UnsignedLong>() {
319             @Override
320             public void onSuccess(final UnsignedLong result) {
321                 final TransactionIdentifier txId = cohortEntry.getTransactionId();
322                 log.debug("{}: Transaction {} committed as {}, sending response to {}", persistenceId(), txId, result,
323                     sender);
324                 cohortEntry.getShard().getDataStore().purgeTransaction(txId, null);
325
326                 cohortCache.remove(cohortEntry.getTransactionId());
327                 sender.tell(CommitTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(),
328                     cohortEntry.getShard().self());
329             }
330
331             @Override
332             public void onFailure(final Throwable failure) {
333                 final TransactionIdentifier txId = cohortEntry.getTransactionId();
334                 log.error("{}, An exception occurred while committing transaction {}", persistenceId(), txId, failure);
335                 cohortEntry.getShard().getDataStore().purgeTransaction(txId, null);
336
337                 cohortCache.remove(cohortEntry.getTransactionId());
338                 sender.tell(new Failure(failure), cohortEntry.getShard().self());
339             }
340         });
341     }
342
343     /**
344      * This method handles the preCommit and commit phases for a transaction.
345      *
346      * @param transactionID the ID of the transaction to commit
347      * @param sender the actor to which to send the response
348      * @param shard the transaction's shard actor
349      */
350     void handleCommit(final Identifier transactionID, final ActorRef sender, final Shard shard) {
351         final CohortEntry cohortEntry = cohortCache.get(transactionID);
352         if (cohortEntry == null) {
353             // Either a long time passed between canCommit and commit and the entry was expired from the cache
354             // or it was aborted.
355             IllegalStateException ex = new IllegalStateException(
356                     String.format("%s: Cannot commit transaction %s - no cohort entry found", name, transactionID));
357             log.error(ex.getMessage());
358             sender.tell(new Failure(ex), shard.self());
359             return;
360         }
361
362         cohortEntry.setReplySender(sender);
363         doCommit(cohortEntry);
364     }
365
366     @SuppressWarnings("checkstyle:IllegalCatch")
367     void handleAbort(final Identifier transactionID, final ActorRef sender, final Shard shard) {
368         CohortEntry cohortEntry = cohortCache.remove(transactionID);
369         if (cohortEntry == null) {
370             return;
371         }
372
373         log.debug("{}: Aborting transaction {}", name, transactionID);
374
375         final ActorRef self = shard.getSelf();
376         cohortEntry.abort(new FutureCallback<Void>() {
377             @Override
378             public void onSuccess(final Void result) {
379                 shard.getDataStore().purgeTransaction(cohortEntry.getTransactionId(), null);
380
381                 if (sender != null) {
382                     sender.tell(AbortTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), self);
383                 }
384             }
385
386             @Override
387             public void onFailure(final Throwable failure) {
388                 log.error("{}: An exception happened during abort", name, failure);
389                 shard.getDataStore().purgeTransaction(cohortEntry.getTransactionId(), null);
390
391                 if (sender != null) {
392                     sender.tell(new Failure(failure), self);
393                 }
394             }
395         });
396
397         shard.getShardMBean().incrementAbortTransactionsCount();
398     }
399
400     void checkForExpiredTransactions(final long timeout, final Shard shard) {
401         Iterator<CohortEntry> iter = cohortCache.values().iterator();
402         while (iter.hasNext()) {
403             CohortEntry cohortEntry = iter.next();
404             if (cohortEntry.isFailed()) {
405                 iter.remove();
406             }
407         }
408     }
409
410     void abortPendingTransactions(final String reason, final Shard shard) {
411         final Failure failure = new Failure(new RuntimeException(reason));
412         Collection<ShardDataTreeCohort> pending = dataTree.getAndClearPendingTransactions();
413
414         log.debug("{}: Aborting {} pending queued transactions", name, pending.size());
415
416         for (ShardDataTreeCohort cohort : pending) {
417             CohortEntry cohortEntry = cohortCache.remove(cohort.getIdentifier());
418             if (cohortEntry == null) {
419                 continue;
420             }
421
422             if (cohortEntry.getReplySender() != null) {
423                 cohortEntry.getReplySender().tell(failure, shard.self());
424             }
425         }
426
427         cohortCache.clear();
428     }
429
430     Collection<?> convertPendingTransactionsToMessages(final int maxModificationsPerBatch) {
431         final Collection<VersionedExternalizableMessage> messages = new ArrayList<>();
432         for (ShardDataTreeCohort cohort : dataTree.getAndClearPendingTransactions()) {
433             CohortEntry cohortEntry = cohortCache.remove(cohort.getIdentifier());
434             if (cohortEntry == null) {
435                 continue;
436             }
437
438             final Deque<BatchedModifications> newMessages = new ArrayDeque<>();
439             cohortEntry.getDataTreeModification().applyToCursor(new AbstractBatchedModificationsCursor() {
440                 @Override
441                 protected BatchedModifications getModifications() {
442                     final BatchedModifications lastBatch = newMessages.peekLast();
443
444                     if (lastBatch != null && lastBatch.getModifications().size() >= maxModificationsPerBatch) {
445                         return lastBatch;
446                     }
447
448                     // Allocate a new message
449                     final BatchedModifications ret = new BatchedModifications(cohortEntry.getTransactionId(),
450                         cohortEntry.getClientVersion());
451                     newMessages.add(ret);
452                     return ret;
453                 }
454             });
455
456             final BatchedModifications last = newMessages.peekLast();
457             if (last != null) {
458                 final boolean immediate = cohortEntry.isDoImmediateCommit();
459                 last.setDoCommitOnReady(immediate);
460                 last.setReady(cohortEntry.getParticipatingShardNames());
461                 last.setTotalMessagesSent(newMessages.size());
462
463                 messages.addAll(newMessages);
464
465                 if (!immediate) {
466                     switch (cohort.getState()) {
467                         case CAN_COMMIT_COMPLETE:
468                         case CAN_COMMIT_PENDING:
469                             messages.add(new CanCommitTransaction(cohortEntry.getTransactionId(),
470                                 cohortEntry.getClientVersion()));
471                             break;
472                         case PRE_COMMIT_COMPLETE:
473                         case PRE_COMMIT_PENDING:
474                             messages.add(new CommitTransaction(cohortEntry.getTransactionId(),
475                                 cohortEntry.getClientVersion()));
476                             break;
477                         default:
478                             break;
479                     }
480                 }
481             }
482         }
483
484         return messages;
485     }
486
487     @VisibleForTesting
488     void setCohortDecorator(final CohortDecorator cohortDecorator) {
489         this.cohortDecorator = cohortDecorator;
490     }
491 }

©2013 OpenDaylight, A Linux Foundation Collaborative Project. All Rights Reserved.
OpenDaylight is a registered trademark of The OpenDaylight Project, Inc.
Linux Foundation and OpenDaylight are registered trademarks of the Linux Foundation.
Linux is a registered trademark of Linus Torvalds.