2 * Copyright (c) 2014 Brocade Communications Systems, Inc. and others. All rights reserved.
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
8 package org.opendaylight.controller.cluster.datastore;
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 java.util.ArrayList;
16 import java.util.Collection;
17 import java.util.Collections;
18 import java.util.HashMap;
19 import java.util.Iterator;
20 import java.util.LinkedList;
21 import java.util.List;
23 import java.util.Queue;
24 import java.util.concurrent.ExecutionException;
25 import org.opendaylight.controller.cluster.datastore.DataTreeCohortActorRegistry.CohortRegistryCommand;
26 import org.opendaylight.controller.cluster.datastore.messages.AbortTransactionReply;
27 import org.opendaylight.controller.cluster.datastore.messages.BatchedModifications;
28 import org.opendaylight.controller.cluster.datastore.messages.BatchedModificationsReply;
29 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransaction;
30 import org.opendaylight.controller.cluster.datastore.messages.CanCommitTransactionReply;
31 import org.opendaylight.controller.cluster.datastore.messages.CommitTransaction;
32 import org.opendaylight.controller.cluster.datastore.messages.ForwardedReadyTransaction;
33 import org.opendaylight.controller.cluster.datastore.messages.ReadyLocalTransaction;
34 import org.opendaylight.controller.cluster.datastore.messages.ReadyTransactionReply;
35 import org.opendaylight.controller.cluster.datastore.utils.AbstractBatchedModificationsCursor;
36 import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException;
37 import org.opendaylight.yangtools.concepts.Identifier;
38 import org.opendaylight.yangtools.yang.model.api.SchemaContext;
39 import org.slf4j.Logger;
42 * Coordinates commits for a shard ensuring only one concurrent 3-phase commit.
44 * @author Thomas Pantelis
46 final class ShardCommitCoordinator {
48 // Interface hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
49 public interface CohortDecorator {
50 ShardDataTreeCohort decorate(Identifier transactionID, ShardDataTreeCohort actual);
53 private final Map<Identifier, CohortEntry> cohortCache = new HashMap<>();
55 private CohortEntry currentCohortEntry;
57 private final ShardDataTree dataTree;
59 private final DataTreeCohortActorRegistry cohortRegistry = new DataTreeCohortActorRegistry();
61 // We use a LinkedList here to avoid synchronization overhead with concurrent queue impls
62 // since this should only be accessed on the shard's dispatcher.
63 private final Queue<CohortEntry> queuedCohortEntries = new LinkedList<>();
65 private int queueCapacity;
67 private final Logger log;
69 private final String name;
71 private final long cacheExpiryTimeoutInMillis;
73 // This is a hook for unit tests to replace or decorate the DOMStoreThreePhaseCommitCohorts.
74 private CohortDecorator cohortDecorator;
76 private ReadyTransactionReply readyTransactionReply;
78 private Runnable runOnPendingTransactionsComplete;
80 ShardCommitCoordinator(ShardDataTree dataTree, long cacheExpiryTimeoutInMillis, int queueCapacity, Logger log,
83 this.queueCapacity = queueCapacity;
86 this.dataTree = Preconditions.checkNotNull(dataTree);
87 this.cacheExpiryTimeoutInMillis = cacheExpiryTimeoutInMillis;
91 return queuedCohortEntries.size();
94 int getCohortCacheSize() {
95 return cohortCache.size();
98 void setQueueCapacity(int queueCapacity) {
99 this.queueCapacity = queueCapacity;
102 private ReadyTransactionReply readyTransactionReply(Shard shard) {
103 if(readyTransactionReply == null) {
104 readyTransactionReply = new ReadyTransactionReply(Serialization.serializedActorPath(shard.self()));
107 return readyTransactionReply;
110 private boolean queueCohortEntry(CohortEntry cohortEntry, ActorRef sender, Shard shard) {
111 if(queuedCohortEntries.size() < queueCapacity) {
112 queuedCohortEntries.offer(cohortEntry);
114 log.debug("{}: Enqueued transaction {}, queue size {}", name, cohortEntry.getTransactionID(),
115 queuedCohortEntries.size());
119 cohortCache.remove(cohortEntry.getTransactionID());
121 final RuntimeException ex = new RuntimeException(
122 String.format("%s: Could not enqueue transaction %s - the maximum commit queue"+
123 " capacity %d has been reached.",
124 name, cohortEntry.getTransactionID(), queueCapacity));
125 log.error(ex.getMessage());
126 sender.tell(new Failure(ex), shard.self());
132 * This method is called to ready a transaction that was prepared by ShardTransaction actor. It caches
133 * the prepared cohort entry for the given transactions ID in preparation for the subsequent 3-phase commit.
135 * @param ready the ForwardedReadyTransaction message to process
136 * @param sender the sender of the message
137 * @param shard the transaction's shard actor
140 void handleForwardedReadyTransaction(ForwardedReadyTransaction ready, ActorRef sender, Shard shard,
141 SchemaContext schema) {
142 log.debug("{}: Readying transaction {}, client version {}", name,
143 ready.getTransactionID(), ready.getTxnClientVersion());
145 final ShardDataTreeCohort cohort = ready.getTransaction().ready();
146 final CohortEntry cohortEntry = CohortEntry.createReady(ready.getTransactionID(), cohort, cohortRegistry,
147 schema, ready.getTxnClientVersion());
148 cohortCache.put(cohortEntry.getTransactionID(), cohortEntry);
150 if(!queueCohortEntry(cohortEntry, sender, shard)) {
154 if(ready.isDoImmediateCommit()) {
155 cohortEntry.setDoImmediateCommit(true);
156 cohortEntry.setReplySender(sender);
157 cohortEntry.setShard(shard);
158 handleCanCommit(cohortEntry);
160 // The caller does not want immediate commit - the 3-phase commit will be coordinated by the
161 // front-end so send back a ReadyTransactionReply with our actor path.
162 sender.tell(readyTransactionReply(shard), shard.self());
167 * This method handles a BatchedModifications message for a transaction being prepared directly on the
168 * Shard actor instead of via a ShardTransaction actor. If there's no currently cached
169 * DOMStoreWriteTransaction, one is created. The batched modifications are applied to the write Tx. If
170 * the BatchedModifications is ready to commit then a DOMStoreThreePhaseCommitCohort is created.
172 * @param batched the BatchedModifications message to process
173 * @param sender the sender of the message
175 void handleBatchedModifications(BatchedModifications batched, ActorRef sender, Shard shard) {
176 CohortEntry cohortEntry = cohortCache.get(batched.getTransactionID());
177 if(cohortEntry == null) {
178 cohortEntry = CohortEntry.createOpen(batched.getTransactionID(),
179 dataTree.newReadWriteTransaction(batched.getTransactionID()),
180 cohortRegistry, dataTree.getSchemaContext(), batched.getVersion());
181 cohortCache.put(cohortEntry.getTransactionID(), cohortEntry);
184 if(log.isDebugEnabled()) {
185 log.debug("{}: Applying {} batched modifications for Tx {}", name,
186 batched.getModifications().size(), batched.getTransactionID());
189 cohortEntry.applyModifications(batched.getModifications());
191 if(batched.isReady()) {
192 if(cohortEntry.getLastBatchedModificationsException() != null) {
193 cohortCache.remove(cohortEntry.getTransactionID());
194 throw cohortEntry.getLastBatchedModificationsException();
197 if(cohortEntry.getTotalBatchedModificationsReceived() != batched.getTotalMessagesSent()) {
198 cohortCache.remove(cohortEntry.getTransactionID());
199 throw new IllegalStateException(String.format(
200 "The total number of batched messages received %d does not match the number sent %d",
201 cohortEntry.getTotalBatchedModificationsReceived(), batched.getTotalMessagesSent()));
204 if(!queueCohortEntry(cohortEntry, sender, shard)) {
208 if(log.isDebugEnabled()) {
209 log.debug("{}: Readying Tx {}, client version {}", name,
210 batched.getTransactionID(), batched.getVersion());
213 cohortEntry.ready(cohortDecorator, batched.isDoCommitOnReady());
215 if(batched.isDoCommitOnReady()) {
216 cohortEntry.setReplySender(sender);
217 cohortEntry.setShard(shard);
218 handleCanCommit(cohortEntry);
220 sender.tell(readyTransactionReply(shard), shard.self());
223 sender.tell(new BatchedModificationsReply(batched.getModifications().size()), shard.self());
228 * This method handles {@link ReadyLocalTransaction} message. All transaction modifications have
229 * been prepared beforehand by the sender and we just need to drive them through into the
232 * @param message the ReadyLocalTransaction message to process
233 * @param sender the sender of the message
234 * @param shard the transaction's shard actor
236 void handleReadyLocalTransaction(ReadyLocalTransaction message, ActorRef sender, Shard shard) {
237 final ShardDataTreeCohort cohort = new SimpleShardDataTreeCohort(dataTree, message.getModification(),
238 message.getTransactionID());
239 final CohortEntry cohortEntry = CohortEntry.createReady(message.getTransactionID(), cohort, cohortRegistry,
240 dataTree.getSchemaContext(), DataStoreVersions.CURRENT_VERSION);
241 cohortCache.put(cohortEntry.getTransactionID(), cohortEntry);
242 cohortEntry.setDoImmediateCommit(message.isDoCommitOnReady());
244 if(!queueCohortEntry(cohortEntry, sender, shard)) {
248 log.debug("{}: Applying local modifications for Tx {}", name, message.getTransactionID());
250 if (message.isDoCommitOnReady()) {
251 cohortEntry.setReplySender(sender);
252 cohortEntry.setShard(shard);
253 handleCanCommit(cohortEntry);
255 sender.tell(readyTransactionReply(shard), shard.self());
259 Collection<BatchedModifications> createForwardedBatchedModifications(final BatchedModifications from,
260 final int maxModificationsPerBatch) {
261 CohortEntry cohortEntry = getAndRemoveCohortEntry(from.getTransactionID());
262 if(cohortEntry == null || cohortEntry.getTransaction() == null) {
263 return Collections.singletonList(from);
266 cohortEntry.applyModifications(from.getModifications());
268 final LinkedList<BatchedModifications> newModifications = new LinkedList<>();
269 cohortEntry.getTransaction().getSnapshot().applyToCursor(new AbstractBatchedModificationsCursor() {
271 protected BatchedModifications getModifications() {
272 if(newModifications.isEmpty() ||
273 newModifications.getLast().getModifications().size() >= maxModificationsPerBatch) {
274 newModifications.add(new BatchedModifications(from.getTransactionID(), from.getVersion()));
277 return newModifications.getLast();
281 BatchedModifications last = newModifications.getLast();
282 last.setDoCommitOnReady(from.isDoCommitOnReady());
283 last.setReady(from.isReady());
284 last.setTotalMessagesSent(newModifications.size());
285 return newModifications;
288 private void handleCanCommit(CohortEntry cohortEntry) {
289 cohortEntry.updateLastAccessTime();
291 if(currentCohortEntry != null) {
292 // There's already a Tx commit in progress so we can't process this entry yet - but it's in the
293 // queue and will get processed after all prior entries complete.
295 if(log.isDebugEnabled()) {
296 log.debug("{}: Commit for Tx {} already in progress - skipping canCommit for {} for now",
297 name, currentCohortEntry.getTransactionID(), cohortEntry.getTransactionID());
303 // No Tx commit currently in progress - check if this entry is the next one in the queue, If so make
304 // it the current entry and proceed with canCommit.
305 // Purposely checking reference equality here.
306 if(queuedCohortEntries.peek() == cohortEntry) {
307 currentCohortEntry = queuedCohortEntries.poll();
308 doCanCommit(currentCohortEntry);
310 if(log.isDebugEnabled()) {
311 log.debug("{}: Tx {} is the next pending canCommit - skipping {} for now", name,
312 queuedCohortEntries.peek() != null ? queuedCohortEntries.peek().getTransactionID() : "???",
313 cohortEntry.getTransactionID());
319 * This method handles the canCommit phase for a transaction.
321 * @param transactionID the ID of the transaction to canCommit
322 * @param sender the actor to which to send the response
323 * @param shard the transaction's shard actor
325 void handleCanCommit(Identifier transactionID, final ActorRef sender, final Shard shard) {
326 // Lookup the cohort entry that was cached previously (or should have been) by
327 // transactionReady (via the ForwardedReadyTransaction message).
328 final CohortEntry cohortEntry = cohortCache.get(transactionID);
329 if(cohortEntry == null) {
330 // Either canCommit was invoked before ready(shouldn't happen) or a long time passed
331 // between canCommit and ready and the entry was expired from the cache.
332 IllegalStateException ex = new IllegalStateException(
333 String.format("%s: No cohort entry found for transaction %s", name, transactionID));
334 log.error(ex.getMessage());
335 sender.tell(new Failure(ex), shard.self());
339 cohortEntry.setReplySender(sender);
340 cohortEntry.setShard(shard);
342 handleCanCommit(cohortEntry);
345 private void doCanCommit(final CohortEntry cohortEntry) {
346 boolean canCommit = false;
348 canCommit = cohortEntry.canCommit();
350 log.debug("{}: canCommit for {}: {}", name, cohortEntry.getTransactionID(), canCommit);
352 if(cohortEntry.isDoImmediateCommit()) {
354 doCommit(cohortEntry);
356 cohortEntry.getReplySender().tell(new Failure(new TransactionCommitFailedException(
357 "Can Commit failed, no detailed cause available.")), cohortEntry.getShard().self());
360 cohortEntry.getReplySender().tell(
361 canCommit ? CanCommitTransactionReply.yes(cohortEntry.getClientVersion()).toSerializable() :
362 CanCommitTransactionReply.no(cohortEntry.getClientVersion()).toSerializable(),
363 cohortEntry.getShard().self());
365 } catch (Exception e) {
366 log.debug("{}: An exception occurred during canCommit", name, e);
368 Throwable failure = e;
369 if(e instanceof ExecutionException) {
370 failure = e.getCause();
373 cohortEntry.getReplySender().tell(new Failure(failure), cohortEntry.getShard().self());
376 // Remove the entry from the cache now.
377 currentTransactionComplete(cohortEntry.getTransactionID(), true);
382 private boolean doCommit(CohortEntry cohortEntry) {
383 log.debug("{}: Committing transaction {}", name, cohortEntry.getTransactionID());
385 boolean success = false;
387 // We perform the preCommit phase here atomically with the commit phase. This is an
388 // optimization to eliminate the overhead of an extra preCommit message. We lose front-end
389 // coordination of preCommit across shards in case of failure but preCommit should not
390 // normally fail since we ensure only one concurrent 3-phase commit.
393 cohortEntry.preCommit();
395 cohortEntry.getShard().continueCommit(cohortEntry);
397 cohortEntry.updateLastAccessTime();
400 } catch (Exception e) {
401 log.error("{} An exception occurred while preCommitting transaction {}",
402 name, cohortEntry.getTransactionID(), e);
403 cohortEntry.getReplySender().tell(new Failure(e), cohortEntry.getShard().self());
405 currentTransactionComplete(cohortEntry.getTransactionID(), true);
412 * This method handles the preCommit and commit phases for a transaction.
414 * @param transactionID the ID of the transaction to commit
415 * @param sender the actor to which to send the response
416 * @param shard the transaction's shard actor
417 * @return true if the transaction was successfully prepared, false otherwise.
419 boolean handleCommit(final Identifier transactionID, final ActorRef sender, final Shard shard) {
420 // Get the current in-progress cohort entry in the commitCoordinator if it corresponds to
422 final CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
423 if(cohortEntry == null) {
424 // We're not the current Tx - the Tx was likely expired b/c it took too long in
425 // between the canCommit and commit messages.
426 IllegalStateException ex = new IllegalStateException(
427 String.format("%s: Cannot commit transaction %s - it is not the current transaction",
428 name, transactionID));
429 log.error(ex.getMessage());
430 sender.tell(new Failure(ex), shard.self());
434 cohortEntry.setReplySender(sender);
435 return doCommit(cohortEntry);
438 void handleAbort(final Identifier transactionID, final ActorRef sender, final Shard shard) {
439 CohortEntry cohortEntry = getCohortEntryIfCurrent(transactionID);
440 if(cohortEntry != null) {
441 // We don't remove the cached cohort entry here (ie pass false) in case the Tx was
442 // aborted during replication in which case we may still commit locally if replication
444 currentTransactionComplete(transactionID, false);
446 cohortEntry = getAndRemoveCohortEntry(transactionID);
449 if(cohortEntry == null) {
453 log.debug("{}: Aborting transaction {}", name, transactionID);
455 final ActorRef self = shard.getSelf();
459 shard.getShardMBean().incrementAbortTransactionsCount();
462 sender.tell(AbortTransactionReply.instance(cohortEntry.getClientVersion()).toSerializable(), self);
464 } catch (Exception e) {
465 log.error("{}: An exception happened during abort", name, e);
468 sender.tell(new Failure(e), self);
473 void checkForExpiredTransactions(final long timeout, final Shard shard) {
474 CohortEntry cohortEntry = getCurrentCohortEntry();
475 if(cohortEntry != null) {
476 if(cohortEntry.isExpired(timeout)) {
477 log.warn("{}: Current transaction {} has timed out after {} ms - aborting",
478 name, cohortEntry.getTransactionID(), timeout);
480 handleAbort(cohortEntry.getTransactionID(), null, shard);
484 cleanupExpiredCohortEntries();
487 void abortPendingTransactions(final String reason, final Shard shard) {
488 if(currentCohortEntry == null && queuedCohortEntries.isEmpty()) {
492 List<CohortEntry> cohortEntries = getAndClearPendingCohortEntries();
494 log.debug("{}: Aborting {} pending queued transactions", name, cohortEntries.size());
496 for(CohortEntry cohortEntry: cohortEntries) {
497 if(cohortEntry.getReplySender() != null) {
498 cohortEntry.getReplySender().tell(new Failure(new RuntimeException(reason)), shard.self());
503 private List<CohortEntry> getAndClearPendingCohortEntries() {
504 List<CohortEntry> cohortEntries = new ArrayList<>();
506 if(currentCohortEntry != null) {
507 cohortEntries.add(currentCohortEntry);
508 cohortCache.remove(currentCohortEntry.getTransactionID());
509 currentCohortEntry = null;
512 for(CohortEntry cohortEntry: queuedCohortEntries) {
513 cohortEntries.add(cohortEntry);
514 cohortCache.remove(cohortEntry.getTransactionID());
517 queuedCohortEntries.clear();
518 return cohortEntries;
521 Collection<Object> convertPendingTransactionsToMessages(final int maxModificationsPerBatch) {
522 if(currentCohortEntry == null && queuedCohortEntries.isEmpty()) {
523 return Collections.emptyList();
526 Collection<Object> messages = new ArrayList<>();
527 List<CohortEntry> cohortEntries = getAndClearPendingCohortEntries();
528 for(CohortEntry cohortEntry: cohortEntries) {
529 if(cohortEntry.isExpired(cacheExpiryTimeoutInMillis) || cohortEntry.isAborted()) {
533 final LinkedList<BatchedModifications> newModifications = new LinkedList<>();
534 cohortEntry.getDataTreeModification().applyToCursor(new AbstractBatchedModificationsCursor() {
536 protected BatchedModifications getModifications() {
537 if(newModifications.isEmpty() ||
538 newModifications.getLast().getModifications().size() >= maxModificationsPerBatch) {
539 newModifications.add(new BatchedModifications(cohortEntry.getTransactionID(),
540 cohortEntry.getClientVersion()));
543 return newModifications.getLast();
547 if(!newModifications.isEmpty()) {
548 BatchedModifications last = newModifications.getLast();
549 last.setDoCommitOnReady(cohortEntry.isDoImmediateCommit());
551 last.setTotalMessagesSent(newModifications.size());
552 messages.addAll(newModifications);
554 if(!cohortEntry.isDoImmediateCommit() && cohortEntry.getState() == CohortEntry.State.CAN_COMMITTED) {
555 messages.add(new CanCommitTransaction(cohortEntry.getTransactionID(),
556 cohortEntry.getClientVersion()));
559 if(!cohortEntry.isDoImmediateCommit() && cohortEntry.getState() == CohortEntry.State.PRE_COMMITTED) {
560 messages.add(new CommitTransaction(cohortEntry.getTransactionID(),
561 cohortEntry.getClientVersion()));
570 * Returns the cohort entry for the Tx commit currently in progress if the given transaction ID
571 * matches the current entry.
573 * @param transactionID the ID of the transaction
574 * @return the current CohortEntry or null if the given transaction ID does not match the
577 CohortEntry getCohortEntryIfCurrent(Identifier transactionID) {
578 if(isCurrentTransaction(transactionID)) {
579 return currentCohortEntry;
585 CohortEntry getCurrentCohortEntry() {
586 return currentCohortEntry;
589 CohortEntry getAndRemoveCohortEntry(Identifier transactionID) {
590 return cohortCache.remove(transactionID);
593 boolean isCurrentTransaction(Identifier transactionID) {
594 return currentCohortEntry != null &&
595 currentCohortEntry.getTransactionID().equals(transactionID);
599 * This method is called when a transaction is complete, successful or not. If the given
600 * given transaction ID matches the current in-progress transaction, the next cohort entry,
601 * if any, is dequeued and processed.
603 * @param transactionID the ID of the completed transaction
604 * @param removeCohortEntry if true the CohortEntry for the transaction is also removed from
607 void currentTransactionComplete(Identifier transactionID, boolean removeCohortEntry) {
608 if(removeCohortEntry) {
609 cohortCache.remove(transactionID);
612 if(isCurrentTransaction(transactionID)) {
613 currentCohortEntry = null;
615 log.debug("{}: currentTransactionComplete: {}", name, transactionID);
617 maybeProcessNextCohortEntry();
621 private void maybeProcessNextCohortEntry() {
622 // Check if there's a next cohort entry waiting in the queue and if it is ready to commit. Also
623 // clean out expired entries.
624 final Iterator<CohortEntry> iter = queuedCohortEntries.iterator();
625 while(iter.hasNext()) {
626 final CohortEntry next = iter.next();
627 if(next.isReadyToCommit()) {
628 if(currentCohortEntry == null) {
629 if(log.isDebugEnabled()) {
630 log.debug("{}: Next entry to canCommit {}", name, next);
634 currentCohortEntry = next;
635 currentCohortEntry.updateLastAccessTime();
636 doCanCommit(currentCohortEntry);
640 } else if(next.isExpired(cacheExpiryTimeoutInMillis)) {
641 log.warn("{}: canCommit for transaction {} was not received within {} ms - entry removed from cache",
642 name, next.getTransactionID(), cacheExpiryTimeoutInMillis);
643 } else if(!next.isAborted()) {
648 cohortCache.remove(next.getTransactionID());
651 maybeRunOperationOnPendingTransactionsComplete();
654 void cleanupExpiredCohortEntries() {
655 maybeProcessNextCohortEntry();
658 void setRunOnPendingTransactionsComplete(Runnable operation) {
659 runOnPendingTransactionsComplete = operation;
660 maybeRunOperationOnPendingTransactionsComplete();
663 private void maybeRunOperationOnPendingTransactionsComplete() {
664 if(runOnPendingTransactionsComplete != null && currentCohortEntry == null && queuedCohortEntries.isEmpty()) {
665 log.debug("{}: Pending transactions complete - running operation {}", name, runOnPendingTransactionsComplete);
667 runOnPendingTransactionsComplete.run();
668 runOnPendingTransactionsComplete = null;
673 void setCohortDecorator(CohortDecorator cohortDecorator) {
674 this.cohortDecorator = cohortDecorator;
677 void processCohortRegistryCommand(ActorRef sender, CohortRegistryCommand message) {
678 cohortRegistry.process(sender, message);