X-Git-Url: https://git.opendaylight.org/gerrit/gitweb?p=controller.git;a=blobdiff_plain;f=opendaylight%2Fmd-sal%2Fsal-distributed-datastore%2Fsrc%2Fmain%2Fjava%2Forg%2Fopendaylight%2Fcontroller%2Fcluster%2Fdatastore%2FShardDataTree.java;h=89fa8fbc2507fc1f25d8de01cabb48a0cfd4359d;hp=56c5eb65bf087c3a0d979de2ecaff7b0a65467a2;hb=a47dd7a5d21ca68804a6d0e2e3ca765f223c2ef4;hpb=6fdcecdc2ecc9f8489de7c72f0709d28b6a1da87 diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java index 56c5eb65bf..89fa8fbc25 100644 --- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java +++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/ShardDataTree.java @@ -7,32 +7,61 @@ */ package org.opendaylight.controller.cluster.datastore; +import akka.actor.ActorRef; +import akka.util.Timeout; import com.google.common.annotations.VisibleForTesting; import com.google.common.base.Optional; -import com.google.common.base.Strings; +import com.google.common.base.Preconditions; +import com.google.common.base.Verify; +import com.google.common.primitives.UnsignedLong; +import java.io.IOException; import java.util.AbstractMap.SimpleEntry; +import java.util.ArrayDeque; +import java.util.ArrayList; +import java.util.Collection; import java.util.HashMap; +import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; +import java.util.Queue; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.TimeoutException; import javax.annotation.concurrent.NotThreadSafe; +import org.opendaylight.controller.cluster.access.concepts.LocalHistoryIdentifier; +import org.opendaylight.controller.cluster.access.concepts.TransactionIdentifier; +import org.opendaylight.controller.cluster.datastore.DataTreeCohortActorRegistry.CohortRegistryCommand; +import org.opendaylight.controller.cluster.datastore.ShardDataTreeCohort.State; +import org.opendaylight.controller.cluster.datastore.persisted.CommitTransactionPayload; +import org.opendaylight.controller.cluster.datastore.persisted.DataTreeCandidateSupplier; +import org.opendaylight.controller.cluster.datastore.persisted.MetadataShardDataTreeSnapshot; +import org.opendaylight.controller.cluster.datastore.persisted.ShardDataTreeSnapshot; +import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload; import org.opendaylight.controller.md.sal.common.api.data.AsyncDataBroker.DataChangeScope; import org.opendaylight.controller.md.sal.common.api.data.AsyncDataChangeListener; +import org.opendaylight.controller.md.sal.common.api.data.OptimisticLockFailedException; +import org.opendaylight.controller.md.sal.common.api.data.TransactionCommitFailedException; import org.opendaylight.controller.md.sal.dom.api.DOMDataTreeChangeListener; -import org.opendaylight.controller.md.sal.dom.store.impl.DOMImmutableDataChangeEvent; -import org.opendaylight.controller.md.sal.dom.store.impl.ResolveDataChangeEventsTask; -import org.opendaylight.controller.md.sal.dom.store.impl.tree.ListenerTree; +import org.opendaylight.controller.md.sal.dom.store.impl.DataChangeListenerRegistration; +import org.opendaylight.yangtools.concepts.Identifier; import org.opendaylight.yangtools.concepts.ListenerRegistration; import org.opendaylight.yangtools.yang.data.api.YangInstanceIdentifier; import org.opendaylight.yangtools.yang.data.api.schema.NormalizedNode; +import org.opendaylight.yangtools.yang.data.api.schema.tree.ConflictingModificationAppliedException; import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidate; +import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidateTip; import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeCandidates; import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeModification; +import org.opendaylight.yangtools.yang.data.api.schema.tree.DataTreeSnapshot; import org.opendaylight.yangtools.yang.data.api.schema.tree.DataValidationFailedException; +import org.opendaylight.yangtools.yang.data.api.schema.tree.ModificationType; import org.opendaylight.yangtools.yang.data.api.schema.tree.TipProducingDataTree; +import org.opendaylight.yangtools.yang.data.api.schema.tree.TreeType; import org.opendaylight.yangtools.yang.data.impl.schema.tree.InMemoryDataTreeFactory; import org.opendaylight.yangtools.yang.model.api.SchemaContext; import org.slf4j.Logger; import org.slf4j.LoggerFactory; +import scala.concurrent.duration.Duration; /** * Internal shard state, similar to a DOMStore, but optimized for use in the actor system, @@ -42,64 +71,137 @@ import org.slf4j.LoggerFactory; * This class is not part of the API contract and is subject to change at any time. */ @NotThreadSafe -@VisibleForTesting -public final class ShardDataTree extends ShardDataTreeTransactionParent { +public class ShardDataTree extends ShardDataTreeTransactionParent { + private static final class CommitEntry { + final SimpleShardDataTreeCohort cohort; + long lastAccess; + + CommitEntry(final SimpleShardDataTreeCohort cohort, final long now) { + this.cohort = Preconditions.checkNotNull(cohort); + lastAccess = now; + } + } + + private static final Timeout COMMIT_STEP_TIMEOUT = new Timeout(Duration.create(5, TimeUnit.SECONDS)); private static final Logger LOG = LoggerFactory.getLogger(ShardDataTree.class); - private static final ShardDataTreeNotificationManager MANAGER = new ShardDataTreeNotificationManager(); - private final Map transactionChains = new HashMap<>(); - private final ShardDataTreeChangePublisher treeChangePublisher = new ShardDataTreeChangePublisher(); - private final ListenerTree listenerTree = ListenerTree.create(); + + private final Map transactionChains = new HashMap<>(); + private final DataTreeCohortActorRegistry cohortRegistry = new DataTreeCohortActorRegistry(); + private final Queue pendingTransactions = new ArrayDeque<>(); + private final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher; + private final ShardDataChangeListenerPublisher dataChangeListenerPublisher; private final TipProducingDataTree dataTree; + private final String logContext; + private final Shard shard; + private Runnable runOnPendingTransactionsComplete; - ShardDataTree(final SchemaContext schemaContext) { - dataTree = InMemoryDataTreeFactory.getInstance().create(); - if (schemaContext != null) { - dataTree.setSchemaContext(schemaContext); - } + private SchemaContext schemaContext; + + public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TipProducingDataTree dataTree, + final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher, + final ShardDataChangeListenerPublisher dataChangeListenerPublisher, final String logContext) { + this.dataTree = dataTree; + updateSchemaContext(schemaContext); + + this.shard = Preconditions.checkNotNull(shard); + this.treeChangeListenerPublisher = Preconditions.checkNotNull(treeChangeListenerPublisher); + this.dataChangeListenerPublisher = Preconditions.checkNotNull(dataChangeListenerPublisher); + this.logContext = Preconditions.checkNotNull(logContext); } - TipProducingDataTree getDataTree() { + public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TreeType treeType, + final ShardDataTreeChangeListenerPublisher treeChangeListenerPublisher, + final ShardDataChangeListenerPublisher dataChangeListenerPublisher, final String logContext) { + this(shard, schemaContext, InMemoryDataTreeFactory.getInstance().create(treeType), + treeChangeListenerPublisher, dataChangeListenerPublisher, logContext); + } + + @VisibleForTesting + public ShardDataTree(final Shard shard, final SchemaContext schemaContext, final TreeType treeType) { + this(shard, schemaContext, treeType, new DefaultShardDataTreeChangeListenerPublisher(), + new DefaultShardDataChangeListenerPublisher(), ""); + } + + String logContext() { + return logContext; + } + + public TipProducingDataTree getDataTree() { return dataTree; } + SchemaContext getSchemaContext() { + return schemaContext; + } + void updateSchemaContext(final SchemaContext schemaContext) { dataTree.setSchemaContext(schemaContext); + this.schemaContext = Preconditions.checkNotNull(schemaContext); } - private ShardDataTreeTransactionChain ensureTransactionChain(final String chainId) { - ShardDataTreeTransactionChain chain = transactionChains.get(chainId); + ShardDataTreeSnapshot takeRecoverySnapshot() { + return new MetadataShardDataTreeSnapshot(dataTree.takeSnapshot().readNode(YangInstanceIdentifier.EMPTY).get()); + } + + void applyRecoveryTransaction(final ReadWriteShardDataTreeTransaction transaction) throws DataValidationFailedException { + // FIXME: purge any outstanding transactions + + final DataTreeModification snapshot = transaction.getSnapshot(); + snapshot.ready(); + + dataTree.validate(snapshot); + dataTree.commit(dataTree.prepare(snapshot)); + } + + private ShardDataTreeTransactionChain ensureTransactionChain(final LocalHistoryIdentifier localHistoryIdentifier) { + ShardDataTreeTransactionChain chain = transactionChains.get(localHistoryIdentifier); if (chain == null) { - chain = new ShardDataTreeTransactionChain(chainId, this); - transactionChains.put(chainId, chain); + chain = new ShardDataTreeTransactionChain(localHistoryIdentifier, this); + transactionChains.put(localHistoryIdentifier, chain); } return chain; } - ReadOnlyShardDataTreeTransaction newReadOnlyTransaction(final String txId, final String chainId) { - if (Strings.isNullOrEmpty(chainId)) { + ReadOnlyShardDataTreeTransaction newReadOnlyTransaction(final TransactionIdentifier txId) { + if (txId.getHistoryId().getHistoryId() == 0) { return new ReadOnlyShardDataTreeTransaction(txId, dataTree.takeSnapshot()); } - return ensureTransactionChain(chainId).newReadOnlyTransaction(txId); + return ensureTransactionChain(txId.getHistoryId()).newReadOnlyTransaction(txId); } - ReadWriteShardDataTreeTransaction newReadWriteTransaction(final String txId, final String chainId) { - if (Strings.isNullOrEmpty(chainId)) { - return new ReadWriteShardDataTreeTransaction(this, txId, dataTree.takeSnapshot().newModification()); + ReadWriteShardDataTreeTransaction newReadWriteTransaction(final TransactionIdentifier txId) { + if (txId.getHistoryId().getHistoryId() == 0) { + return new ReadWriteShardDataTreeTransaction(ShardDataTree.this, txId, dataTree.takeSnapshot() + .newModification()); } - return ensureTransactionChain(chainId).newReadWriteTransaction(txId); + return ensureTransactionChain(txId.getHistoryId()).newReadWriteTransaction(txId); } - void notifyListeners(final DataTreeCandidate candidate) { - LOG.debug("Notifying listeners on candidate {}", candidate); + public void notifyListeners(final DataTreeCandidate candidate) { + treeChangeListenerPublisher.publishChanges(candidate, logContext); + dataChangeListenerPublisher.publishChanges(candidate, logContext); + } - // DataTreeChanges first, as they are more light-weight - treeChangePublisher.publishChanges(candidate); + void notifyOfInitialData(final DataChangeListenerRegistration>> listenerReg, final Optional currentState) { + if (currentState.isPresent()) { + ShardDataChangeListenerPublisher localPublisher = dataChangeListenerPublisher.newInstance(); + localPublisher.registerDataChangeListener(listenerReg.getPath(), listenerReg.getInstance(), + listenerReg.getScope()); + localPublisher.publishChanges(currentState.get(), logContext); + } + } - // DataChanges second, as they are heavier - ResolveDataChangeEventsTask.create(candidate, listenerTree).resolve(MANAGER); + void notifyOfInitialData(final YangInstanceIdentifier path, final DOMDataTreeChangeListener listener, + final Optional currentState) { + if (currentState.isPresent()) { + ShardDataTreeChangeListenerPublisher localPublisher = treeChangeListenerPublisher.newInstance(); + localPublisher.registerTreeChangeListener(path, listener); + localPublisher.publishChanges(currentState.get(), logContext); + } } void closeAllTransactionChains() { @@ -110,55 +212,51 @@ public final class ShardDataTree extends ShardDataTreeTransactionParent { transactionChains.clear(); } - void closeTransactionChain(final String transactionChainId) { + void closeTransactionChain(final LocalHistoryIdentifier transactionChainId) { final ShardDataTreeTransactionChain chain = transactionChains.remove(transactionChainId); if (chain != null) { chain.close(); } else { - LOG.debug("Closing non-existent transaction chain {}", transactionChainId); + LOG.debug("{}: Closing non-existent transaction chain {}", logContext, transactionChainId); } } - Entry>>, DOMImmutableDataChangeEvent> registerChangeListener( - final YangInstanceIdentifier path, - final AsyncDataChangeListener> listener, final DataChangeScope scope) { - final ListenerRegistration>> reg = - listenerTree.registerDataChangeListener(path, listener, scope); + Entry>>, + Optional> registerChangeListener(final YangInstanceIdentifier path, + final AsyncDataChangeListener> listener, + final DataChangeScope scope) { + final DataChangeListenerRegistration>> reg = + dataChangeListenerPublisher.registerDataChangeListener(path, listener, scope); - final Optional> currentState = dataTree.takeSnapshot().readNode(path); - final DOMImmutableDataChangeEvent event; - if (currentState.isPresent()) { - final NormalizedNode data = currentState.get(); - event = DOMImmutableDataChangeEvent.builder(DataChangeScope.BASE).setAfter(data).addCreated(path, data).build(); - } else { - event = null; - } + return new SimpleEntry<>(reg, readCurrentData()); + } - return new SimpleEntry<>(reg, event); + private Optional readCurrentData() { + final Optional> currentState = dataTree.takeSnapshot().readNode(YangInstanceIdentifier.EMPTY); + return currentState.isPresent() ? Optional.of(DataTreeCandidates.fromNormalizedNode( + YangInstanceIdentifier.EMPTY, currentState.get())) : Optional.absent(); } - Entry, DataTreeCandidate> registerTreeChangeListener(final YangInstanceIdentifier path, - final DOMDataTreeChangeListener listener) { - final ListenerRegistration reg = treeChangePublisher.registerTreeChangeListener(path, listener); + public Entry, Optional> registerTreeChangeListener( + final YangInstanceIdentifier path, final DOMDataTreeChangeListener listener) { + final ListenerRegistration reg = treeChangeListenerPublisher.registerTreeChangeListener( + path, listener); - final Optional> currentState = dataTree.takeSnapshot().readNode(path); - final DataTreeCandidate event; - if (currentState.isPresent()) { - event = DataTreeCandidates.fromNormalizedNode(path, currentState.get()); - } else { - event = null; - } - return new SimpleEntry<>(reg, event); + return new SimpleEntry<>(reg, readCurrentData()); + } + + int getQueueSize() { + return pendingTransactions.size(); } - void applyForeignCandidate(final String identifier, final DataTreeCandidate foreign) throws DataValidationFailedException { - LOG.debug("Applying foreign transaction {}", identifier); + void applyForeignCandidate(final Identifier identifier, final DataTreeCandidate foreign) throws DataValidationFailedException { + LOG.debug("{}: Applying foreign transaction {}", logContext, identifier); final DataTreeModification mod = dataTree.takeSnapshot().newModification(); DataTreeCandidates.applyToModification(mod, foreign); mod.ready(); - LOG.trace("Applying foreign modification {}", mod); + LOG.trace("{}: Applying foreign modification {}", logContext, mod); dataTree.validate(mod); final DataTreeCandidate candidate = dataTree.prepare(mod); dataTree.commit(candidate); @@ -174,7 +272,345 @@ public final class ShardDataTree extends ShardDataTreeTransactionParent { ShardDataTreeCohort finishTransaction(final ReadWriteShardDataTreeTransaction transaction) { final DataTreeModification snapshot = transaction.getSnapshot(); snapshot.ready(); - return new SimpleShardDataTreeCohort(this, snapshot); + + return createReadyCohort(transaction.getId(), snapshot); + } + + public Optional> readNode(final YangInstanceIdentifier path) { + return dataTree.takeSnapshot().readNode(path); + } + + public DataTreeSnapshot takeSnapshot() { + return dataTree.takeSnapshot(); + } + + public DataTreeModification newModification() { + return dataTree.takeSnapshot().newModification(); + } + + @VisibleForTesting + // FIXME: This should be removed, it violates encapsulation + public DataTreeCandidate commit(final DataTreeModification modification) throws DataValidationFailedException { + modification.ready(); + dataTree.validate(modification); + DataTreeCandidateTip candidate = dataTree.prepare(modification); + dataTree.commit(candidate); + return candidate; + } + + public Collection getAndClearPendingTransactions() { + Collection ret = new ArrayList<>(pendingTransactions.size()); + for(CommitEntry entry: pendingTransactions) { + ret.add(entry.cohort); + } + + pendingTransactions.clear(); + return ret; + } + + private void processNextTransaction() { + while (!pendingTransactions.isEmpty()) { + final CommitEntry entry = pendingTransactions.peek(); + final SimpleShardDataTreeCohort cohort = entry.cohort; + final DataTreeModification modification = cohort.getDataTreeModification(); + + if(cohort.getState() != State.CAN_COMMIT_PENDING) { + break; + } + + LOG.debug("{}: Validating transaction {}", logContext, cohort.getIdentifier()); + Exception cause; + try { + dataTree.validate(modification); + LOG.debug("{}: Transaction {} validated", logContext, cohort.getIdentifier()); + cohort.successfulCanCommit(); + entry.lastAccess = shard.ticker().read(); + return; + } catch (ConflictingModificationAppliedException e) { + LOG.warn("{}: Store Tx {}: Conflicting modification for path {}.", logContext, cohort.getIdentifier(), + e.getPath()); + cause = new OptimisticLockFailedException("Optimistic lock failed.", e); + } catch (DataValidationFailedException e) { + LOG.warn("{}: Store Tx {}: Data validation failed for path {}.", logContext, cohort.getIdentifier(), + e.getPath(), e); + + // For debugging purposes, allow dumping of the modification. Coupled with the above + // precondition log, it should allow us to understand what went on. + LOG.debug("{}: Store Tx {}: modifications: {} tree: {}", cohort.getIdentifier(), modification, dataTree); + cause = new TransactionCommitFailedException("Data did not pass validation.", e); + } catch (Exception e) { + LOG.warn("{}: Unexpected failure in validation phase", logContext, e); + cause = e; + } + + // Failure path: propagate the failure, remove the transaction from the queue and loop to the next one + pendingTransactions.poll().cohort.failedCanCommit(cause); + } + + maybeRunOperationOnPendingTransactionsComplete(); } + void startCanCommit(final SimpleShardDataTreeCohort cohort) { + final SimpleShardDataTreeCohort current = pendingTransactions.peek().cohort; + if (!cohort.equals(current)) { + LOG.debug("{}: Transaction {} scheduled for canCommit step", logContext, cohort.getIdentifier()); + return; + } + + processNextTransaction(); + } + + private void failPreCommit(final Exception cause) { + shard.getShardMBean().incrementFailedTransactionsCount(); + pendingTransactions.poll().cohort.failedPreCommit(cause); + processNextTransaction(); + } + + void startPreCommit(final SimpleShardDataTreeCohort cohort) { + final CommitEntry entry = pendingTransactions.peek(); + Preconditions.checkState(entry != null, "Attempted to pre-commit of %s when no transactions pending", cohort); + + final SimpleShardDataTreeCohort current = entry.cohort; + Verify.verify(cohort.equals(current), "Attempted to pre-commit %s while %s is pending", cohort, current); + final DataTreeCandidateTip candidate; + try { + candidate = dataTree.prepare(cohort.getDataTreeModification()); + } catch (Exception e) { + failPreCommit(e); + return; + } + + try { + cohort.userPreCommit(candidate); + } catch (ExecutionException | TimeoutException e) { + failPreCommit(e); + return; + } + + entry.lastAccess = shard.ticker().read(); + cohort.successfulPreCommit(candidate); + } + + private void failCommit(final Exception cause) { + shard.getShardMBean().incrementFailedTransactionsCount(); + pendingTransactions.poll().cohort.failedCommit(cause); + processNextTransaction(); + } + + private void finishCommit(final SimpleShardDataTreeCohort cohort) { + final TransactionIdentifier txId = cohort.getIdentifier(); + final DataTreeCandidate candidate = cohort.getCandidate(); + + LOG.debug("{}: Resuming commit of transaction {}", logContext, txId); + + try { + try { + dataTree.commit(candidate); + } catch (IllegalStateException e) { + // We may get a "store tree and candidate base differ" IllegalStateException from commit under + // certain edge case scenarios so we'll try to re-apply the candidate from scratch as a last + // resort. Eg, we're a follower and a tx payload is replicated but the leader goes down before + // applying it to the state. We then become the leader and a second tx is pre-committed and + // replicated. When consensus occurs, this will cause the first tx to be applied as a foreign + // candidate via applyState prior to the second tx. Since the second tx has already been + // pre-committed, when it gets here to commit it will get an IllegalStateException. + + // FIXME - this is not an ideal way to handle this scenario. This is temporary - a cleaner + // solution will be forthcoming. + + LOG.debug("{}: Commit failed for transaction {} - retrying as foreign candidate", logContext, txId, e); + applyForeignCandidate(txId, candidate); + } + } catch (Exception e) { + failCommit(e); + return; + } + + shard.getShardMBean().incrementCommittedTransactionCount(); + shard.getShardMBean().setLastCommittedTransactionTime(System.currentTimeMillis()); + + // FIXME: propagate journal index + + pendingTransactions.poll().cohort.successfulCommit(UnsignedLong.ZERO); + + LOG.trace("{}: Transaction {} committed, proceeding to notify", logContext, txId); + notifyListeners(candidate); + + processNextTransaction(); + } + + void startCommit(final SimpleShardDataTreeCohort cohort, final DataTreeCandidate candidate) { + final CommitEntry entry = pendingTransactions.peek(); + Preconditions.checkState(entry != null, "Attempted to start commit of %s when no transactions pending", cohort); + + final SimpleShardDataTreeCohort current = entry.cohort; + Verify.verify(cohort.equals(current), "Attempted to commit %s while %s is pending", cohort, current); + + if (shard.canSkipPayload() || candidate.getRootNode().getModificationType() == ModificationType.UNMODIFIED) { + LOG.debug("{}: No replication required, proceeding to finish commit", logContext); + finishCommit(cohort); + return; + } + + final TransactionIdentifier txId = cohort.getIdentifier(); + final Payload payload; + try { + payload = CommitTransactionPayload.create(txId, candidate); + } catch (IOException e) { + LOG.error("{}: Failed to encode transaction {} candidate {}", logContext, txId, candidate, e); + pendingTransactions.poll().cohort.failedCommit(e); + return; + } + + // Once completed, we will continue via payloadReplicationComplete + entry.lastAccess = shard.ticker().read(); + shard.persistPayload(txId, payload); + LOG.debug("{}: Transaction {} submitted to persistence", logContext, txId); + } + + private void payloadReplicationComplete(final TransactionIdentifier txId, final DataTreeCandidateSupplier payload) { + final CommitEntry current = pendingTransactions.peek(); + if (current == null) { + LOG.warn("{}: No outstanding transactions, ignoring consensus on transaction {}", logContext, txId); + return; + } + + if (!current.cohort.getIdentifier().equals(txId)) { + LOG.warn("{}: Head of queue is {}, ignoring consensus on transaction {}", logContext, + current.cohort.getIdentifier(), txId); + return; + } + + finishCommit(current.cohort); + } + + void payloadReplicationComplete(final Identifier identifier, final DataTreeCandidateSupplier payload) { + // For now we do not care about anything else but transactions + Verify.verify(identifier instanceof TransactionIdentifier); + payloadReplicationComplete((TransactionIdentifier)identifier, payload); + } + + void processCohortRegistryCommand(final ActorRef sender, final CohortRegistryCommand message) { + cohortRegistry.process(sender, message); + } + + ShardDataTreeCohort createReadyCohort(final TransactionIdentifier txId, + final DataTreeModification modification) { + SimpleShardDataTreeCohort cohort = new SimpleShardDataTreeCohort(this, modification, txId, + cohortRegistry.createCohort(schemaContext, txId, COMMIT_STEP_TIMEOUT)); + pendingTransactions.add(new CommitEntry(cohort, shard.ticker().read())); + return cohort; + } + + void applyStateFromLeader(final Identifier identifier, final DataTreeCandidateSupplier payload) + throws DataValidationFailedException, IOException { + applyForeignCandidate(identifier, payload.getCandidate().getValue()); + } + + void checkForExpiredTransactions(final long transactionCommitTimeoutMillis) { + final long timeout = TimeUnit.MILLISECONDS.toNanos(transactionCommitTimeoutMillis); + final long now = shard.ticker().read(); + final CommitEntry currentTx = pendingTransactions.peek(); + if (currentTx != null && currentTx.lastAccess + timeout < now) { + LOG.warn("{}: Current transaction {} has timed out after {} ms in state {}", logContext, + currentTx.cohort.getIdentifier(), transactionCommitTimeoutMillis, currentTx.cohort.getState()); + boolean processNext = true; + switch (currentTx.cohort.getState()) { + case CAN_COMMIT_PENDING: + pendingTransactions.poll().cohort.failedCanCommit(new TimeoutException()); + break; + case CAN_COMMIT_COMPLETE: + pendingTransactions.poll().cohort.reportFailure(new TimeoutException()); + break; + case PRE_COMMIT_PENDING: + pendingTransactions.poll().cohort.failedPreCommit(new TimeoutException()); + break; + case PRE_COMMIT_COMPLETE: + // FIXME: this is a legacy behavior problem. Three-phase commit protocol specifies that after we + // are ready we should commit the transaction, not abort it. Our current software stack does + // not allow us to do that consistently, because we persist at the time of commit, hence + // we can end up in a state where we have pre-committed a transaction, then a leader failover + // occurred ... the new leader does not see the pre-committed transaction and does not have + // a running timer. To fix this we really need two persistence events. + // + // The first one, done at pre-commit time will hold the transaction payload. When consensus + // is reached, we exit the pre-commit phase and start the pre-commit timer. Followers do not + // apply the state in this event. + // + // The second one, done at commit (or abort) time holds only the transaction identifier and + // signals to followers that the state should (or should not) be applied. + // + // In order to make the pre-commit timer working across failovers, though, we need + // a per-shard cluster-wide monotonic time, so a follower becoming the leader can accurately + // restart the timer. + pendingTransactions.poll().cohort.reportFailure(new TimeoutException()); + break; + case COMMIT_PENDING: + LOG.warn("{}: Transaction {} is still committing, cannot abort", logContext, + currentTx.cohort.getIdentifier()); + currentTx.lastAccess = now; + processNext = false; + return; + case ABORTED: + case COMMITTED: + case FAILED: + case READY: + default: + pendingTransactions.poll(); + } + + if (processNext) { + processNextTransaction(); + } + } + } + + void startAbort(final SimpleShardDataTreeCohort cohort) { + final Iterator it = pendingTransactions.iterator(); + if (!it.hasNext()) { + LOG.debug("{}: no open transaction while attempting to abort {}", logContext, cohort.getIdentifier()); + return; + } + + // First entry is special, as it may already be committing + final CommitEntry first = it.next(); + if (cohort.equals(first.cohort)) { + if (cohort.getState() != State.COMMIT_PENDING) { + LOG.debug("{}: aborted head of queue {} in state {}", logContext, cohort.getIdentifier(), + cohort.getIdentifier()); + pendingTransactions.poll(); + processNextTransaction(); + } else { + LOG.warn("{}: transaction {} is committing, skipping abort", logContext, cohort.getIdentifier()); + } + + return; + } + + while (it.hasNext()) { + final CommitEntry e = it.next(); + if (cohort.equals(e.cohort)) { + LOG.debug("{}: aborting queued transaction {}", logContext, cohort.getIdentifier()); + it.remove(); + return; + } + } + + LOG.debug("{}: aborted transaction {} not found in the queue", logContext, cohort.getIdentifier()); + } + + void setRunOnPendingTransactionsComplete(final Runnable operation) { + runOnPendingTransactionsComplete = operation; + maybeRunOperationOnPendingTransactionsComplete(); + } + + private void maybeRunOperationOnPendingTransactionsComplete() { + if (runOnPendingTransactionsComplete != null && pendingTransactions.isEmpty()) { + LOG.debug("{}: Pending transactions complete - running operation {}", logContext, + runOnPendingTransactionsComplete); + + runOnPendingTransactionsComplete.run(); + runOnPendingTransactionsComplete = null; + } + } }