/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.cassandra.service; import java.io.IOException; import java.lang.management.ManagementFactory; import java.net.InetAddress; import java.nio.ByteBuffer; import java.util.*; import java.util.concurrent.*; import java.util.concurrent.atomic.AtomicInteger; import java.util.concurrent.atomic.AtomicLong; import javax.management.MBeanServer; import javax.management.ObjectName; import com.google.common.base.Predicate; import com.google.common.cache.CacheLoader; import com.google.common.collect.*; import com.google.common.primitives.Ints; import com.google.common.util.concurrent.Uninterruptibles; import org.apache.commons.lang3.StringUtils; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.apache.cassandra.batchlog.Batch; import org.apache.cassandra.batchlog.BatchlogManager; import org.apache.cassandra.concurrent.Stage; import org.apache.cassandra.concurrent.StageManager; import org.apache.cassandra.schema.TableMetadata; import org.apache.cassandra.config.DatabaseDescriptor; import org.apache.cassandra.schema.Schema; import org.apache.cassandra.schema.SchemaConstants; import org.apache.cassandra.db.*; import org.apache.cassandra.db.filter.DataLimits; import org.apache.cassandra.db.filter.TombstoneOverwhelmingException; import org.apache.cassandra.db.partitions.*; import org.apache.cassandra.db.rows.RowIterator; import org.apache.cassandra.db.view.ViewUtils; import org.apache.cassandra.dht.*; import org.apache.cassandra.exceptions.*; import org.apache.cassandra.gms.FailureDetector; import org.apache.cassandra.gms.Gossiper; import org.apache.cassandra.hints.Hint; import org.apache.cassandra.hints.HintsService; import org.apache.cassandra.index.Index; import org.apache.cassandra.io.util.DataOutputBuffer; import org.apache.cassandra.locator.*; import org.apache.cassandra.metrics.*; import org.apache.cassandra.net.*; import org.apache.cassandra.service.paxos.Commit; import org.apache.cassandra.service.paxos.PaxosState; import org.apache.cassandra.service.paxos.PrepareCallback; import org.apache.cassandra.service.paxos.ProposeCallback; import org.apache.cassandra.net.MessagingService.Verb; import org.apache.cassandra.tracing.Tracing; import org.apache.cassandra.triggers.TriggerExecutor; import org.apache.cassandra.utils.*; import org.apache.cassandra.utils.AbstractIterator; public class StorageProxy implements StorageProxyMBean { public static final String MBEAN_NAME = "org.apache.cassandra.db:type=StorageProxy"; private static final Logger logger = LoggerFactory.getLogger(StorageProxy.class); public static final String UNREACHABLE = "UNREACHABLE"; private static final WritePerformer standardWritePerformer; private static final WritePerformer counterWritePerformer; private static final WritePerformer counterWriteOnCoordinatorPerformer; public static final StorageProxy instance = new StorageProxy(); private static volatile int maxHintsInProgress = 128 * FBUtilities.getAvailableProcessors(); private static final CacheLoader<InetAddress, AtomicInteger> hintsInProgress = new CacheLoader<InetAddress, AtomicInteger>() { public AtomicInteger load(InetAddress inetAddress) { return new AtomicInteger(0); } }; private static final ClientRequestMetrics readMetrics = new ClientRequestMetrics("Read"); private static final ClientRequestMetrics rangeMetrics = new ClientRequestMetrics("RangeSlice"); private static final ClientWriteRequestMetrics writeMetrics = new ClientWriteRequestMetrics("Write"); private static final CASClientWriteRequestMetrics casWriteMetrics = new CASClientWriteRequestMetrics("CASWrite"); private static final CASClientRequestMetrics casReadMetrics = new CASClientRequestMetrics("CASRead"); private static final ViewWriteMetrics viewWriteMetrics = new ViewWriteMetrics("ViewWrite"); private static final Map<ConsistencyLevel, ClientRequestMetrics> readMetricsMap = new EnumMap<>(ConsistencyLevel.class); private static final Map<ConsistencyLevel, ClientWriteRequestMetrics> writeMetricsMap = new EnumMap<>(ConsistencyLevel.class); private static final double CONCURRENT_SUBREQUESTS_MARGIN = 0.10; private StorageProxy() { } static { MBeanServer mbs = ManagementFactory.getPlatformMBeanServer(); try { mbs.registerMBean(instance, new ObjectName(MBEAN_NAME)); } catch (Exception e) { throw new RuntimeException(e); } HintsService.instance.registerMBean(); HintedHandOffManager.instance.registerMBean(); standardWritePerformer = new WritePerformer() { public void apply(IMutation mutation, Iterable<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler, String localDataCenter, ConsistencyLevel consistency_level) throws OverloadedException { assert mutation instanceof Mutation; sendToHintedEndpoints((Mutation) mutation, targets, responseHandler, localDataCenter, Stage.MUTATION); } }; /* * We execute counter writes in 2 places: either directly in the coordinator node if it is a replica, or * in CounterMutationVerbHandler on a replica othewise. The write must be executed on the COUNTER_MUTATION stage * but on the latter case, the verb handler already run on the COUNTER_MUTATION stage, so we must not execute the * underlying on the stage otherwise we risk a deadlock. Hence two different performer. */ counterWritePerformer = new WritePerformer() { public void apply(IMutation mutation, Iterable<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler, String localDataCenter, ConsistencyLevel consistencyLevel) { counterWriteTask(mutation, targets, responseHandler, localDataCenter).run(); } }; counterWriteOnCoordinatorPerformer = new WritePerformer() { public void apply(IMutation mutation, Iterable<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler, String localDataCenter, ConsistencyLevel consistencyLevel) { StageManager.getStage(Stage.COUNTER_MUTATION) .execute(counterWriteTask(mutation, targets, responseHandler, localDataCenter)); } }; for(ConsistencyLevel level : ConsistencyLevel.values()) { readMetricsMap.put(level, new ClientRequestMetrics("Read-" + level.name())); writeMetricsMap.put(level, new ClientWriteRequestMetrics("Write-" + level.name())); } } /** * Apply @param updates if and only if the current values in the row for @param key * match the provided @param conditions. The algorithm is "raw" Paxos: that is, Paxos * minus leader election -- any node in the cluster may propose changes for any row, * which (that is, the row) is the unit of values being proposed, not single columns. * * The Paxos cohort is only the replicas for the given key, not the entire cluster. * So we expect performance to be reasonable, but CAS is still intended to be used * "when you really need it," not for all your updates. * * There are three phases to Paxos: * 1. Prepare: the coordinator generates a ballot (timeUUID in our case) and asks replicas to (a) promise * not to accept updates from older ballots and (b) tell us about the most recent update it has already * accepted. * 2. Accept: if a majority of replicas reply, the coordinator asks replicas to accept the value of the * highest proposal ballot it heard about, or a new value if no in-progress proposals were reported. * 3. Commit (Learn): if a majority of replicas acknowledge the accept request, we can commit the new * value. * * Commit procedure is not covered in "Paxos Made Simple," and only briefly mentioned in "Paxos Made Live," * so here is our approach: * 3a. The coordinator sends a commit message to all replicas with the ballot and value. * 3b. Because of 1-2, this will be the highest-seen commit ballot. The replicas will note that, * and send it with subsequent promise replies. This allows us to discard acceptance records * for successfully committed replicas, without allowing incomplete proposals to commit erroneously * later on. * * Note that since we are performing a CAS rather than a simple update, we perform a read (of committed * values) between the prepare and accept phases. This gives us a slightly longer window for another * coordinator to come along and trump our own promise with a newer one but is otherwise safe. * * @param keyspaceName the keyspace for the CAS * @param cfName the column family for the CAS * @param key the row key for the row to CAS * @param request the conditions for the CAS to apply as well as the update to perform if the conditions hold. * @param consistencyForPaxos the consistency for the paxos prepare and propose round. This can only be either SERIAL or LOCAL_SERIAL. * @param consistencyForCommit the consistency for write done during the commit phase. This can be anything, except SERIAL or LOCAL_SERIAL. * * @return null if the operation succeeds in updating the row, or the current values corresponding to conditions. * (since, if the CAS doesn't succeed, it means the current value do not match the conditions). */ public static RowIterator cas(String keyspaceName, String cfName, DecoratedKey key, CASRequest request, ConsistencyLevel consistencyForPaxos, ConsistencyLevel consistencyForCommit, ClientState state, long queryStartNanoTime) throws UnavailableException, IsBootstrappingException, RequestFailureException, RequestTimeoutException, InvalidRequestException { final long startTimeForMetrics = System.nanoTime(); int contentions = 0; try { consistencyForPaxos.validateForCas(); consistencyForCommit.validateForCasCommit(keyspaceName); TableMetadata metadata = Schema.instance.getTableMetadata(keyspaceName, cfName); long timeout = TimeUnit.MILLISECONDS.toNanos(DatabaseDescriptor.getCasContentionTimeout()); while (System.nanoTime() - queryStartNanoTime < timeout) { // for simplicity, we'll do a single liveness check at the start of each attempt Pair<List<InetAddress>, Integer> p = getPaxosParticipants(metadata, key, consistencyForPaxos); List<InetAddress> liveEndpoints = p.left; int requiredParticipants = p.right; final Pair<UUID, Integer> pair = beginAndRepairPaxos(queryStartNanoTime, key, metadata, liveEndpoints, requiredParticipants, consistencyForPaxos, consistencyForCommit, true, state); final UUID ballot = pair.left; contentions += pair.right; // read the current values and check they validate the conditions Tracing.trace("Reading existing values for CAS precondition"); SinglePartitionReadCommand readCommand = request.readCommand(FBUtilities.nowInSeconds()); ConsistencyLevel readConsistency = consistencyForPaxos == ConsistencyLevel.LOCAL_SERIAL ? ConsistencyLevel.LOCAL_QUORUM : ConsistencyLevel.QUORUM; FilteredPartition current; try (RowIterator rowIter = readOne(readCommand, readConsistency, queryStartNanoTime)) { current = FilteredPartition.create(rowIter); } if (!request.appliesTo(current)) { Tracing.trace("CAS precondition does not match current values {}", current); casWriteMetrics.conditionNotMet.inc(); return current.rowIterator(); } // finish the paxos round w/ the desired updates // TODO turn null updates into delete? PartitionUpdate updates = request.makeUpdates(current); long size = updates.dataSize(); casWriteMetrics.mutationSize.update(size); writeMetricsMap.get(consistencyForPaxos).mutationSize.update(size); // Apply triggers to cas updates. A consideration here is that // triggers emit Mutations, and so a given trigger implementation // may generate mutations for partitions other than the one this // paxos round is scoped for. In this case, TriggerExecutor will // validate that the generated mutations are targetted at the same // partition as the initial updates and reject (via an // InvalidRequestException) any which aren't. updates = TriggerExecutor.instance.execute(updates); Commit proposal = Commit.newProposal(ballot, updates); Tracing.trace("CAS precondition is met; proposing client-requested updates for {}", ballot); if (proposePaxos(proposal, liveEndpoints, requiredParticipants, true, consistencyForPaxos, queryStartNanoTime)) { commitPaxos(proposal, consistencyForCommit, true, queryStartNanoTime); Tracing.trace("CAS successful"); return null; } Tracing.trace("Paxos proposal not accepted (pre-empted by a higher ballot)"); contentions++; Uninterruptibles.sleepUninterruptibly(ThreadLocalRandom.current().nextInt(100), TimeUnit.MILLISECONDS); // continue to retry } throw new WriteTimeoutException(WriteType.CAS, consistencyForPaxos, 0, consistencyForPaxos.blockFor(Keyspace.open(keyspaceName))); } catch (WriteTimeoutException|ReadTimeoutException e) { casWriteMetrics.timeouts.mark(); writeMetricsMap.get(consistencyForPaxos).timeouts.mark(); throw e; } catch (WriteFailureException|ReadFailureException e) { casWriteMetrics.failures.mark(); writeMetricsMap.get(consistencyForPaxos).failures.mark(); throw e; } catch(UnavailableException e) { casWriteMetrics.unavailables.mark(); writeMetricsMap.get(consistencyForPaxos).unavailables.mark(); throw e; } finally { recordCasContention(contentions); final long latency = System.nanoTime() - startTimeForMetrics; casWriteMetrics.addNano(latency); writeMetricsMap.get(consistencyForPaxos).addNano(latency); } } private static void recordCasContention(int contentions) { if(contentions > 0) casWriteMetrics.contention.update(contentions); } private static Predicate<InetAddress> sameDCPredicateFor(final String dc) { final IEndpointSnitch snitch = DatabaseDescriptor.getEndpointSnitch(); return new Predicate<InetAddress>() { public boolean apply(InetAddress host) { return dc.equals(snitch.getDatacenter(host)); } }; } private static Pair<List<InetAddress>, Integer> getPaxosParticipants(TableMetadata metadata, DecoratedKey key, ConsistencyLevel consistencyForPaxos) throws UnavailableException { Token tk = key.getToken(); List<InetAddress> naturalEndpoints = StorageService.instance.getNaturalEndpoints(metadata.keyspace, tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, metadata.keyspace); if (consistencyForPaxos == ConsistencyLevel.LOCAL_SERIAL) { // Restrict naturalEndpoints and pendingEndpoints to node in the local DC only String localDc = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getBroadcastAddress()); Predicate<InetAddress> isLocalDc = sameDCPredicateFor(localDc); naturalEndpoints = ImmutableList.copyOf(Iterables.filter(naturalEndpoints, isLocalDc)); pendingEndpoints = ImmutableList.copyOf(Iterables.filter(pendingEndpoints, isLocalDc)); } int participants = pendingEndpoints.size() + naturalEndpoints.size(); int requiredParticipants = participants / 2 + 1; // See CASSANDRA-8346, CASSANDRA-833 List<InetAddress> liveEndpoints = ImmutableList.copyOf(Iterables.filter(Iterables.concat(naturalEndpoints, pendingEndpoints), IAsyncCallback.isAlive)); if (liveEndpoints.size() < requiredParticipants) throw new UnavailableException(consistencyForPaxos, requiredParticipants, liveEndpoints.size()); // We cannot allow CAS operations with 2 or more pending endpoints, see #8346. // Note that we fake an impossible number of required nodes in the unavailable exception // to nail home the point that it's an impossible operation no matter how many nodes are live. if (pendingEndpoints.size() > 1) throw new UnavailableException(String.format("Cannot perform LWT operation as there is more than one (%d) pending range movement", pendingEndpoints.size()), consistencyForPaxos, participants + 1, liveEndpoints.size()); return Pair.create(liveEndpoints, requiredParticipants); } /** * begin a Paxos session by sending a prepare request and completing any in-progress requests seen in the replies * * @return the Paxos ballot promised by the replicas if no in-progress requests were seen and a quorum of * nodes have seen the mostRecentCommit. Otherwise, return null. */ private static Pair<UUID, Integer> beginAndRepairPaxos(long queryStartNanoTime, DecoratedKey key, TableMetadata metadata, List<InetAddress> liveEndpoints, int requiredParticipants, ConsistencyLevel consistencyForPaxos, ConsistencyLevel consistencyForCommit, final boolean isWrite, ClientState state) throws WriteTimeoutException, WriteFailureException { long timeout = TimeUnit.MILLISECONDS.toNanos(DatabaseDescriptor.getCasContentionTimeout()); PrepareCallback summary = null; int contentions = 0; while (System.nanoTime() - queryStartNanoTime < timeout) { // We want a timestamp that is guaranteed to be unique for that node (so that the ballot is globally unique), but if we've got a prepare rejected // already we also want to make sure we pick a timestamp that has a chance to be promised, i.e. one that is greater that the most recently known // in progress (#5667). Lastly, we don't want to use a timestamp that is older than the last one assigned by ClientState or operations may appear // out-of-order (#7801). long minTimestampMicrosToUse = summary == null ? Long.MIN_VALUE : 1 + UUIDGen.microsTimestamp(summary.mostRecentInProgressCommit.ballot); long ballotMicros = state.getTimestampForPaxos(minTimestampMicrosToUse); // Note that ballotMicros is not guaranteed to be unique if two proposal are being handled concurrently by the same coordinator. But we still // need ballots to be unique for each proposal so we have to use getRandomTimeUUIDFromMicros. UUID ballot = UUIDGen.getRandomTimeUUIDFromMicros(ballotMicros); // prepare Tracing.trace("Preparing {}", ballot); Commit toPrepare = Commit.newPrepare(key, metadata, ballot); summary = preparePaxos(toPrepare, liveEndpoints, requiredParticipants, consistencyForPaxos, queryStartNanoTime); if (!summary.promised) { Tracing.trace("Some replicas have already promised a higher ballot than ours; aborting"); contentions++; // sleep a random amount to give the other proposer a chance to finish Uninterruptibles.sleepUninterruptibly(ThreadLocalRandom.current().nextInt(100), TimeUnit.MILLISECONDS); continue; } Commit inProgress = summary.mostRecentInProgressCommitWithUpdate; Commit mostRecent = summary.mostRecentCommit; // If we have an in-progress ballot greater than the MRC we know, then it's an in-progress round that // needs to be completed, so do it. if (!inProgress.update.isEmpty() && inProgress.isAfter(mostRecent)) { Tracing.trace("Finishing incomplete paxos round {}", inProgress); if(isWrite) casWriteMetrics.unfinishedCommit.inc(); else casReadMetrics.unfinishedCommit.inc(); Commit refreshedInProgress = Commit.newProposal(ballot, inProgress.update); if (proposePaxos(refreshedInProgress, liveEndpoints, requiredParticipants, false, consistencyForPaxos, queryStartNanoTime)) { try { commitPaxos(refreshedInProgress, consistencyForCommit, false, queryStartNanoTime); } catch (WriteTimeoutException e) { recordCasContention(contentions); // We're still doing preparation for the paxos rounds, so we want to use the CAS (see CASSANDRA-8672) throw new WriteTimeoutException(WriteType.CAS, e.consistency, e.received, e.blockFor); } } else { Tracing.trace("Some replicas have already promised a higher ballot than ours; aborting"); // sleep a random amount to give the other proposer a chance to finish contentions++; Uninterruptibles.sleepUninterruptibly(ThreadLocalRandom.current().nextInt(100), TimeUnit.MILLISECONDS); } continue; } // To be able to propose our value on a new round, we need a quorum of replica to have learn the previous one. Why is explained at: // https://issues.apache.org/jira/browse/CASSANDRA-5062?focusedCommentId=13619810&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13619810) // Since we waited for quorum nodes, if some of them haven't seen the last commit (which may just be a timing issue, but may also // mean we lost messages), we pro-actively "repair" those nodes, and retry. int nowInSec = Ints.checkedCast(TimeUnit.MICROSECONDS.toSeconds(ballotMicros)); Iterable<InetAddress> missingMRC = summary.replicasMissingMostRecentCommit(metadata, nowInSec); if (Iterables.size(missingMRC) > 0) { Tracing.trace("Repairing replicas that missed the most recent commit"); sendCommit(mostRecent, missingMRC); // TODO: provided commits don't invalid the prepare we just did above (which they don't), we could just wait // for all the missingMRC to acknowledge this commit and then move on with proposing our value. But that means // adding the ability to have commitPaxos block, which is exactly CASSANDRA-5442 will do. So once we have that // latter ticket, we can pass CL.ALL to the commit above and remove the 'continue'. continue; } return Pair.create(ballot, contentions); } recordCasContention(contentions); throw new WriteTimeoutException(WriteType.CAS, consistencyForPaxos, 0, consistencyForPaxos.blockFor(Keyspace.open(metadata.keyspace))); } /** * Unlike commitPaxos, this does not wait for replies */ private static void sendCommit(Commit commit, Iterable<InetAddress> replicas) { MessageOut<Commit> message = new MessageOut<Commit>(MessagingService.Verb.PAXOS_COMMIT, commit, Commit.serializer); for (InetAddress target : replicas) MessagingService.instance().sendOneWay(message, target); } private static PrepareCallback preparePaxos(Commit toPrepare, List<InetAddress> endpoints, int requiredParticipants, ConsistencyLevel consistencyForPaxos, long queryStartNanoTime) throws WriteTimeoutException { PrepareCallback callback = new PrepareCallback(toPrepare.update.partitionKey(), toPrepare.update.metadata(), requiredParticipants, consistencyForPaxos, queryStartNanoTime); MessageOut<Commit> message = new MessageOut<Commit>(MessagingService.Verb.PAXOS_PREPARE, toPrepare, Commit.serializer); for (InetAddress target : endpoints) MessagingService.instance().sendRR(message, target, callback); callback.await(); return callback; } private static boolean proposePaxos(Commit proposal, List<InetAddress> endpoints, int requiredParticipants, boolean timeoutIfPartial, ConsistencyLevel consistencyLevel, long queryStartNanoTime) throws WriteTimeoutException { ProposeCallback callback = new ProposeCallback(endpoints.size(), requiredParticipants, !timeoutIfPartial, consistencyLevel, queryStartNanoTime); MessageOut<Commit> message = new MessageOut<Commit>(MessagingService.Verb.PAXOS_PROPOSE, proposal, Commit.serializer); for (InetAddress target : endpoints) MessagingService.instance().sendRR(message, target, callback); callback.await(); if (callback.isSuccessful()) return true; if (timeoutIfPartial && !callback.isFullyRefused()) throw new WriteTimeoutException(WriteType.CAS, consistencyLevel, callback.getAcceptCount(), requiredParticipants); return false; } private static void commitPaxos(Commit proposal, ConsistencyLevel consistencyLevel, boolean shouldHint, long queryStartNanoTime) throws WriteTimeoutException { boolean shouldBlock = consistencyLevel != ConsistencyLevel.ANY; Keyspace keyspace = Keyspace.open(proposal.update.metadata().keyspace); Token tk = proposal.update.partitionKey().getToken(); List<InetAddress> naturalEndpoints = StorageService.instance.getNaturalEndpoints(keyspace.getName(), tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspace.getName()); AbstractWriteResponseHandler<Commit> responseHandler = null; if (shouldBlock) { AbstractReplicationStrategy rs = keyspace.getReplicationStrategy(); responseHandler = rs.getWriteResponseHandler(naturalEndpoints, pendingEndpoints, consistencyLevel, null, WriteType.SIMPLE, queryStartNanoTime); responseHandler.setSupportsBackPressure(false); } MessageOut<Commit> message = new MessageOut<Commit>(MessagingService.Verb.PAXOS_COMMIT, proposal, Commit.serializer); for (InetAddress destination : Iterables.concat(naturalEndpoints, pendingEndpoints)) { checkHintOverload(destination); if (FailureDetector.instance.isAlive(destination)) { if (shouldBlock) { if (canDoLocalRequest(destination)) commitPaxosLocal(message, responseHandler); else MessagingService.instance().sendRR(message, destination, responseHandler, shouldHint); } else { MessagingService.instance().sendOneWay(message, destination); } } else { if (responseHandler != null) { responseHandler.expired(); } if (shouldHint) { submitHint(proposal.makeMutation(), destination, null); } } } if (shouldBlock) responseHandler.get(); } /** * Commit a PAXOS task locally, and if the task times out rather then submitting a real hint * submit a fake one that executes immediately on the mutation stage, but generates the necessary backpressure * signal for hints */ private static void commitPaxosLocal(final MessageOut<Commit> message, final AbstractWriteResponseHandler<?> responseHandler) { StageManager.getStage(MessagingService.verbStages.get(MessagingService.Verb.PAXOS_COMMIT)).maybeExecuteImmediately(new LocalMutationRunnable() { public void runMayThrow() { try { PaxosState.commit(message.payload); if (responseHandler != null) responseHandler.response(null); } catch (Exception ex) { if (!(ex instanceof WriteTimeoutException)) logger.error("Failed to apply paxos commit locally : {}", ex); responseHandler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.UNKNOWN); } } @Override protected Verb verb() { return MessagingService.Verb.PAXOS_COMMIT; } }); } /** * Use this method to have these Mutations applied * across all replicas. This method will take care * of the possibility of a replica being down and hint * the data across to some other replica. * * @param mutations the mutations to be applied across the replicas * @param consistency_level the consistency level for the operation * @param queryStartNanoTime the value of System.nanoTime() when the query started to be processed */ public static void mutate(Collection<? extends IMutation> mutations, ConsistencyLevel consistency_level, long queryStartNanoTime) throws UnavailableException, OverloadedException, WriteTimeoutException, WriteFailureException { Tracing.trace("Determining replicas for mutation"); final String localDataCenter = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getBroadcastAddress()); long startTime = System.nanoTime(); List<AbstractWriteResponseHandler<IMutation>> responseHandlers = new ArrayList<>(mutations.size()); try { for (IMutation mutation : mutations) { if (mutation instanceof CounterMutation) { responseHandlers.add(mutateCounter((CounterMutation)mutation, localDataCenter, queryStartNanoTime)); } else { WriteType wt = mutations.size() <= 1 ? WriteType.SIMPLE : WriteType.UNLOGGED_BATCH; responseHandlers.add(performWrite(mutation, consistency_level, localDataCenter, standardWritePerformer, null, wt, queryStartNanoTime)); } } // wait for writes. throws TimeoutException if necessary for (AbstractWriteResponseHandler<IMutation> responseHandler : responseHandlers) { responseHandler.get(); } } catch (WriteTimeoutException|WriteFailureException ex) { if (consistency_level == ConsistencyLevel.ANY) { hintMutations(mutations); } else { if (ex instanceof WriteFailureException) { writeMetrics.failures.mark(); writeMetricsMap.get(consistency_level).failures.mark(); WriteFailureException fe = (WriteFailureException)ex; Tracing.trace("Write failure; received {} of {} required replies, failed {} requests", fe.received, fe.blockFor, fe.failureReasonByEndpoint.size()); } else { writeMetrics.timeouts.mark(); writeMetricsMap.get(consistency_level).timeouts.mark(); WriteTimeoutException te = (WriteTimeoutException)ex; Tracing.trace("Write timeout; received {} of {} required replies", te.received, te.blockFor); } throw ex; } } catch (UnavailableException e) { writeMetrics.unavailables.mark(); writeMetricsMap.get(consistency_level).unavailables.mark(); Tracing.trace("Unavailable"); throw e; } catch (OverloadedException e) { writeMetrics.unavailables.mark(); writeMetricsMap.get(consistency_level).unavailables.mark(); Tracing.trace("Overloaded"); throw e; } finally { long latency = System.nanoTime() - startTime; writeMetrics.addNano(latency); writeMetricsMap.get(consistency_level).addNano(latency); } } /** * Hint all the mutations (except counters, which can't be safely retried). This means * we'll re-hint any successful ones; doesn't seem worth it to track individual success * just for this unusual case. * * Only used for CL.ANY * * @param mutations the mutations that require hints */ private static void hintMutations(Collection<? extends IMutation> mutations) { for (IMutation mutation : mutations) if (!(mutation instanceof CounterMutation)) hintMutation((Mutation) mutation); Tracing.trace("Wrote hints to satisfy CL.ANY after no replicas acknowledged the write"); } private static void hintMutation(Mutation mutation) { String keyspaceName = mutation.getKeyspaceName(); Token token = mutation.key().getToken(); Iterable<InetAddress> endpoints = StorageService.instance.getNaturalAndPendingEndpoints(keyspaceName, token); ArrayList<InetAddress> endpointsToHint = new ArrayList<>(Iterables.size(endpoints)); // local writes can timeout, but cannot be dropped (see LocalMutationRunnable and CASSANDRA-6510), // so there is no need to hint or retry. for (InetAddress target : endpoints) if (!target.equals(FBUtilities.getBroadcastAddress()) && shouldHint(target)) endpointsToHint.add(target); submitHint(mutation, endpointsToHint, null); } public boolean appliesLocally(Mutation mutation) { String keyspaceName = mutation.getKeyspaceName(); Token token = mutation.key().getToken(); InetAddress local = FBUtilities.getBroadcastAddress(); return StorageService.instance.getNaturalEndpoints(keyspaceName, token).contains(local) || StorageService.instance.getTokenMetadata().pendingEndpointsFor(token, keyspaceName).contains(local); } /** * Use this method to have these Mutations applied * across all replicas. * * @param mutations the mutations to be applied across the replicas * @param writeCommitLog if commitlog should be written * @param baseComplete time from epoch in ms that the local base mutation was(or will be) completed * @param queryStartNanoTime the value of System.nanoTime() when the query started to be processed */ public static void mutateMV(ByteBuffer dataKey, Collection<Mutation> mutations, boolean writeCommitLog, AtomicLong baseComplete, long queryStartNanoTime) throws UnavailableException, OverloadedException, WriteTimeoutException { Tracing.trace("Determining replicas for mutation"); final String localDataCenter = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getBroadcastAddress()); long startTime = System.nanoTime(); try { // if we haven't joined the ring, write everything to batchlog because paired replicas may be stale final UUID batchUUID = UUIDGen.getTimeUUID(); if (StorageService.instance.isStarting() || StorageService.instance.isJoining() || StorageService.instance.isMoving()) { BatchlogManager.store(Batch.createLocal(batchUUID, FBUtilities.timestampMicros(), mutations), writeCommitLog); } else { List<WriteResponseHandlerWrapper> wrappers = new ArrayList<>(mutations.size()); List<Mutation> nonPairedMutations = new LinkedList<>(); Token baseToken = StorageService.instance.getTokenMetadata().partitioner.getToken(dataKey); ConsistencyLevel consistencyLevel = ConsistencyLevel.ONE; //Since the base -> view replication is 1:1 we only need to store the BL locally final Collection<InetAddress> batchlogEndpoints = Collections.singleton(FBUtilities.getBroadcastAddress()); BatchlogResponseHandler.BatchlogCleanup cleanup = new BatchlogResponseHandler.BatchlogCleanup(mutations.size(), () -> asyncRemoveFromBatchlog(batchlogEndpoints, batchUUID)); // add a handler for each mutation - includes checking availability, but doesn't initiate any writes, yet for (Mutation mutation : mutations) { String keyspaceName = mutation.getKeyspaceName(); Token tk = mutation.key().getToken(); Optional<InetAddress> pairedEndpoint = ViewUtils.getViewNaturalEndpoint(keyspaceName, baseToken, tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspaceName); if (pairedEndpoint.isPresent()) { // When local node is the endpoint and there are no pending nodes we can // Just apply the mutation locally. if (pairedEndpoint.get().equals(FBUtilities.getBroadcastAddress()) && pendingEndpoints.isEmpty() && StorageService.instance.isJoined()) try { mutation.apply(writeCommitLog); } catch (Exception exc) { logger.error("Error applying local view update to keyspace {}: {}", mutation.getKeyspaceName(), mutation); throw exc; } else { wrappers.add(wrapViewBatchResponseHandler(mutation, consistencyLevel, consistencyLevel, Collections.singletonList(pairedEndpoint.get()), baseComplete, WriteType.BATCH, cleanup, queryStartNanoTime)); } } else { //if there are no paired endpoints there are probably range movements going on, //so we write to the local batchlog to replay later if (pendingEndpoints.isEmpty()) logger.warn("Received base materialized view mutation for key {} that does not belong " + "to this node. There is probably a range movement happening (move or decommission)," + "but this node hasn't updated its ring metadata yet. Adding mutation to " + "local batchlog to be replayed later.", mutation.key()); nonPairedMutations.add(mutation); } } if (!wrappers.isEmpty()) { // Apply to local batchlog memtable in this thread BatchlogManager.store(Batch.createLocal(batchUUID, FBUtilities.timestampMicros(), Lists.transform(wrappers, w -> w.mutation)), writeCommitLog); // now actually perform the writes and wait for them to complete asyncWriteBatchedMutations(wrappers, localDataCenter, Stage.VIEW_MUTATION); } if (!nonPairedMutations.isEmpty()) { BatchlogManager.store(Batch.createLocal(batchUUID, FBUtilities.timestampMicros(), nonPairedMutations), writeCommitLog); } } } finally { viewWriteMetrics.addNano(System.nanoTime() - startTime); } } @SuppressWarnings("unchecked") public static void mutateWithTriggers(Collection<? extends IMutation> mutations, ConsistencyLevel consistencyLevel, boolean mutateAtomically, long queryStartNanoTime) throws WriteTimeoutException, WriteFailureException, UnavailableException, OverloadedException, InvalidRequestException { Collection<Mutation> augmented = TriggerExecutor.instance.execute(mutations); boolean updatesView = Keyspace.open(mutations.iterator().next().getKeyspaceName()) .viewManager .updatesAffectView(mutations, true); long size = IMutation.dataSize(mutations); writeMetrics.mutationSize.update(size); writeMetricsMap.get(consistencyLevel).mutationSize.update(size); if (augmented != null) mutateAtomically(augmented, consistencyLevel, updatesView, queryStartNanoTime); else { if (mutateAtomically || updatesView) mutateAtomically((Collection<Mutation>) mutations, consistencyLevel, updatesView, queryStartNanoTime); else mutate(mutations, consistencyLevel, queryStartNanoTime); } } /** * See mutate. Adds additional steps before and after writing a batch. * Before writing the batch (but after doing availability check against the FD for the row replicas): * write the entire batch to a batchlog elsewhere in the cluster. * After: remove the batchlog entry (after writing hints for the batch rows, if necessary). * * @param mutations the Mutations to be applied across the replicas * @param consistency_level the consistency level for the operation * @param requireQuorumForRemove at least a quorum of nodes will see update before deleting batchlog * @param queryStartNanoTime the value of System.nanoTime() when the query started to be processed */ public static void mutateAtomically(Collection<Mutation> mutations, ConsistencyLevel consistency_level, boolean requireQuorumForRemove, long queryStartNanoTime) throws UnavailableException, OverloadedException, WriteTimeoutException { Tracing.trace("Determining replicas for atomic batch"); long startTime = System.nanoTime(); List<WriteResponseHandlerWrapper> wrappers = new ArrayList<WriteResponseHandlerWrapper>(mutations.size()); String localDataCenter = DatabaseDescriptor.getEndpointSnitch().getDatacenter(FBUtilities.getBroadcastAddress()); try { // If we are requiring quorum nodes for removal, we upgrade consistency level to QUORUM unless we already // require ALL, or EACH_QUORUM. This is so that *at least* QUORUM nodes see the update. ConsistencyLevel batchConsistencyLevel = requireQuorumForRemove ? ConsistencyLevel.QUORUM : consistency_level; switch (consistency_level) { case ALL: case EACH_QUORUM: batchConsistencyLevel = consistency_level; } final Collection<InetAddress> batchlogEndpoints = getBatchlogEndpoints(localDataCenter, batchConsistencyLevel); final UUID batchUUID = UUIDGen.getTimeUUID(); BatchlogResponseHandler.BatchlogCleanup cleanup = new BatchlogResponseHandler.BatchlogCleanup(mutations.size(), () -> asyncRemoveFromBatchlog(batchlogEndpoints, batchUUID)); // add a handler for each mutation - includes checking availability, but doesn't initiate any writes, yet for (Mutation mutation : mutations) { WriteResponseHandlerWrapper wrapper = wrapBatchResponseHandler(mutation, consistency_level, batchConsistencyLevel, WriteType.BATCH, cleanup, queryStartNanoTime); // exit early if we can't fulfill the CL at this time. wrapper.handler.assureSufficientLiveNodes(); wrappers.add(wrapper); } // write to the batchlog syncWriteToBatchlog(mutations, batchlogEndpoints, batchUUID, queryStartNanoTime); // now actually perform the writes and wait for them to complete syncWriteBatchedMutations(wrappers, localDataCenter, Stage.MUTATION); } catch (UnavailableException e) { writeMetrics.unavailables.mark(); writeMetricsMap.get(consistency_level).unavailables.mark(); Tracing.trace("Unavailable"); throw e; } catch (WriteTimeoutException e) { writeMetrics.timeouts.mark(); writeMetricsMap.get(consistency_level).timeouts.mark(); Tracing.trace("Write timeout; received {} of {} required replies", e.received, e.blockFor); throw e; } catch (WriteFailureException e) { writeMetrics.failures.mark(); writeMetricsMap.get(consistency_level).failures.mark(); Tracing.trace("Write failure; received {} of {} required replies", e.received, e.blockFor); throw e; } finally { long latency = System.nanoTime() - startTime; writeMetrics.addNano(latency); writeMetricsMap.get(consistency_level).addNano(latency); } } public static boolean canDoLocalRequest(InetAddress replica) { return replica.equals(FBUtilities.getBroadcastAddress()); } private static void syncWriteToBatchlog(Collection<Mutation> mutations, Collection<InetAddress> endpoints, UUID uuid, long queryStartNanoTime) throws WriteTimeoutException, WriteFailureException { WriteResponseHandler<?> handler = new WriteResponseHandler<>(endpoints, Collections.<InetAddress>emptyList(), endpoints.size() == 1 ? ConsistencyLevel.ONE : ConsistencyLevel.TWO, Keyspace.open(SchemaConstants.SYSTEM_KEYSPACE_NAME), null, WriteType.BATCH_LOG, queryStartNanoTime); Batch batch = Batch.createLocal(uuid, FBUtilities.timestampMicros(), mutations); MessageOut<Batch> message = new MessageOut<>(MessagingService.Verb.BATCH_STORE, batch, Batch.serializer); for (InetAddress target : endpoints) { logger.trace("Sending batchlog store request {} to {} for {} mutations", batch.id, target, batch.size()); if (canDoLocalRequest(target)) performLocally(Stage.MUTATION, Optional.empty(), () -> BatchlogManager.store(batch), handler); else MessagingService.instance().sendRR(message, target, handler); } handler.get(); } private static void asyncRemoveFromBatchlog(Collection<InetAddress> endpoints, UUID uuid) { MessageOut<UUID> message = new MessageOut<>(MessagingService.Verb.BATCH_REMOVE, uuid, UUIDSerializer.serializer); for (InetAddress target : endpoints) { if (logger.isTraceEnabled()) logger.trace("Sending batchlog remove request {} to {}", uuid, target); if (canDoLocalRequest(target)) performLocally(Stage.MUTATION, () -> BatchlogManager.remove(uuid)); else MessagingService.instance().sendOneWay(message, target); } } private static void asyncWriteBatchedMutations(List<WriteResponseHandlerWrapper> wrappers, String localDataCenter, Stage stage) { for (WriteResponseHandlerWrapper wrapper : wrappers) { Iterable<InetAddress> endpoints = Iterables.concat(wrapper.handler.naturalEndpoints, wrapper.handler.pendingEndpoints); try { sendToHintedEndpoints(wrapper.mutation, endpoints, wrapper.handler, localDataCenter, stage); } catch (OverloadedException | WriteTimeoutException e) { wrapper.handler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.UNKNOWN); } } } private static void syncWriteBatchedMutations(List<WriteResponseHandlerWrapper> wrappers, String localDataCenter, Stage stage) throws WriteTimeoutException, OverloadedException { for (WriteResponseHandlerWrapper wrapper : wrappers) { Iterable<InetAddress> endpoints = Iterables.concat(wrapper.handler.naturalEndpoints, wrapper.handler.pendingEndpoints); sendToHintedEndpoints(wrapper.mutation, endpoints, wrapper.handler, localDataCenter, stage); } for (WriteResponseHandlerWrapper wrapper : wrappers) wrapper.handler.get(); } /** * Perform the write of a mutation given a WritePerformer. * Gather the list of write endpoints, apply locally and/or forward the mutation to * said write endpoint (deletaged to the actual WritePerformer) and wait for the * responses based on consistency level. * * @param mutation the mutation to be applied * @param consistency_level the consistency level for the write operation * @param performer the WritePerformer in charge of appliying the mutation * given the list of write endpoints (either standardWritePerformer for * standard writes or counterWritePerformer for counter writes). * @param callback an optional callback to be run if and when the write is * @param queryStartNanoTime the value of System.nanoTime() when the query started to be processed */ public static AbstractWriteResponseHandler<IMutation> performWrite(IMutation mutation, ConsistencyLevel consistency_level, String localDataCenter, WritePerformer performer, Runnable callback, WriteType writeType, long queryStartNanoTime) throws UnavailableException, OverloadedException { String keyspaceName = mutation.getKeyspaceName(); AbstractReplicationStrategy rs = Keyspace.open(keyspaceName).getReplicationStrategy(); Token tk = mutation.key().getToken(); List<InetAddress> naturalEndpoints = StorageService.instance.getNaturalEndpoints(keyspaceName, tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspaceName); AbstractWriteResponseHandler<IMutation> responseHandler = rs.getWriteResponseHandler(naturalEndpoints, pendingEndpoints, consistency_level, callback, writeType, queryStartNanoTime); // exit early if we can't fulfill the CL at this time responseHandler.assureSufficientLiveNodes(); performer.apply(mutation, Iterables.concat(naturalEndpoints, pendingEndpoints), responseHandler, localDataCenter, consistency_level); return responseHandler; } // same as performWrites except does not initiate writes (but does perform availability checks). private static WriteResponseHandlerWrapper wrapBatchResponseHandler(Mutation mutation, ConsistencyLevel consistency_level, ConsistencyLevel batchConsistencyLevel, WriteType writeType, BatchlogResponseHandler.BatchlogCleanup cleanup, long queryStartNanoTime) { Keyspace keyspace = Keyspace.open(mutation.getKeyspaceName()); AbstractReplicationStrategy rs = keyspace.getReplicationStrategy(); String keyspaceName = mutation.getKeyspaceName(); Token tk = mutation.key().getToken(); List<InetAddress> naturalEndpoints = StorageService.instance.getNaturalEndpoints(keyspaceName, tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspaceName); AbstractWriteResponseHandler<IMutation> writeHandler = rs.getWriteResponseHandler(naturalEndpoints, pendingEndpoints, consistency_level, null, writeType, queryStartNanoTime); BatchlogResponseHandler<IMutation> batchHandler = new BatchlogResponseHandler<>(writeHandler, batchConsistencyLevel.blockFor(keyspace), cleanup, queryStartNanoTime); return new WriteResponseHandlerWrapper(batchHandler, mutation); } /** * Same as performWrites except does not initiate writes (but does perform availability checks). * Keeps track of ViewWriteMetrics */ private static WriteResponseHandlerWrapper wrapViewBatchResponseHandler(Mutation mutation, ConsistencyLevel consistency_level, ConsistencyLevel batchConsistencyLevel, List<InetAddress> naturalEndpoints, AtomicLong baseComplete, WriteType writeType, BatchlogResponseHandler.BatchlogCleanup cleanup, long queryStartNanoTime) { Keyspace keyspace = Keyspace.open(mutation.getKeyspaceName()); AbstractReplicationStrategy rs = keyspace.getReplicationStrategy(); String keyspaceName = mutation.getKeyspaceName(); Token tk = mutation.key().getToken(); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspaceName); AbstractWriteResponseHandler<IMutation> writeHandler = rs.getWriteResponseHandler(naturalEndpoints, pendingEndpoints, consistency_level, () -> { long delay = Math.max(0, System.currentTimeMillis() - baseComplete.get()); viewWriteMetrics.viewWriteLatency.update(delay, TimeUnit.MILLISECONDS); }, writeType, queryStartNanoTime); BatchlogResponseHandler<IMutation> batchHandler = new ViewWriteMetricsWrapped(writeHandler, batchConsistencyLevel.blockFor(keyspace), cleanup, queryStartNanoTime); return new WriteResponseHandlerWrapper(batchHandler, mutation); } // used by atomic_batch_mutate to decouple availability check from the write itself, caches consistency level and endpoints. private static class WriteResponseHandlerWrapper { final BatchlogResponseHandler<IMutation> handler; final Mutation mutation; WriteResponseHandlerWrapper(BatchlogResponseHandler<IMutation> handler, Mutation mutation) { this.handler = handler; this.mutation = mutation; } } /* * Replicas are picked manually: * - replicas should be alive according to the failure detector * - replicas should be in the local datacenter * - choose min(2, number of qualifying candiates above) * - allow the local node to be the only replica only if it's a single-node DC */ private static Collection<InetAddress> getBatchlogEndpoints(String localDataCenter, ConsistencyLevel consistencyLevel) throws UnavailableException { TokenMetadata.Topology topology = StorageService.instance.getTokenMetadata().cachedOnlyTokenMap().getTopology(); Multimap<String, InetAddress> localEndpoints = HashMultimap.create(topology.getDatacenterRacks().get(localDataCenter)); String localRack = DatabaseDescriptor.getEndpointSnitch().getRack(FBUtilities.getBroadcastAddress()); Collection<InetAddress> chosenEndpoints = new BatchlogManager.EndpointFilter(localRack, localEndpoints).filter(); if (chosenEndpoints.isEmpty()) { if (consistencyLevel == ConsistencyLevel.ANY) return Collections.singleton(FBUtilities.getBroadcastAddress()); throw new UnavailableException(ConsistencyLevel.ONE, 1, 0); } return chosenEndpoints; } /** * Send the mutations to the right targets, write it locally if it corresponds or writes a hint when the node * is not available. * * Note about hints: * <pre> * {@code * | Hinted Handoff | Consist. Level | * | on | >=1 | --> wait for hints. We DO NOT notify the handler with handler.response() for hints; * | on | ANY | --> wait for hints. Responses count towards consistency. * | off | >=1 | --> DO NOT fire hints. And DO NOT wait for them to complete. * | off | ANY | --> DO NOT fire hints. And DO NOT wait for them to complete. * } * </pre> * * @throws OverloadedException if the hints cannot be written/enqueued */ public static void sendToHintedEndpoints(final Mutation mutation, Iterable<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler, String localDataCenter, Stage stage) throws OverloadedException { int targetsSize = Iterables.size(targets); // this dc replicas: Collection<InetAddress> localDc = null; // extra-datacenter replicas, grouped by dc Map<String, Collection<InetAddress>> dcGroups = null; // only need to create a Message for non-local writes MessageOut<Mutation> message = null; boolean insertLocal = false; ArrayList<InetAddress> endpointsToHint = null; List<InetAddress> backPressureHosts = null; for (InetAddress destination : targets) { checkHintOverload(destination); if (FailureDetector.instance.isAlive(destination)) { if (canDoLocalRequest(destination)) { insertLocal = true; } else { // belongs on a different server if (message == null) message = mutation.createMessage(); String dc = DatabaseDescriptor.getEndpointSnitch().getDatacenter(destination); // direct writes to local DC or old Cassandra versions // (1.1 knows how to forward old-style String message IDs; updated to int in 2.0) if (localDataCenter.equals(dc)) { if (localDc == null) localDc = new ArrayList<>(targetsSize); localDc.add(destination); } else { Collection<InetAddress> messages = (dcGroups != null) ? dcGroups.get(dc) : null; if (messages == null) { messages = new ArrayList<>(3); // most DCs will have <= 3 replicas if (dcGroups == null) dcGroups = new HashMap<>(); dcGroups.put(dc, messages); } messages.add(destination); } if (backPressureHosts == null) backPressureHosts = new ArrayList<>(targetsSize); backPressureHosts.add(destination); } } else { //Immediately mark the response as expired since the request will not be sent responseHandler.expired(); if (shouldHint(destination)) { if (endpointsToHint == null) endpointsToHint = new ArrayList<>(targetsSize); endpointsToHint.add(destination); } } } if (backPressureHosts != null) MessagingService.instance().applyBackPressure(backPressureHosts, responseHandler.currentTimeout()); if (endpointsToHint != null) submitHint(mutation, endpointsToHint, responseHandler); if (insertLocal) performLocally(stage, Optional.of(mutation), mutation::apply, responseHandler); if (localDc != null) { for (InetAddress destination : localDc) MessagingService.instance().sendRR(message, destination, responseHandler, true); } if (dcGroups != null) { // for each datacenter, send the message to one node to relay the write to other replicas for (Collection<InetAddress> dcTargets : dcGroups.values()) sendMessagesToNonlocalDC(message, dcTargets, responseHandler); } } private static void checkHintOverload(InetAddress destination) { // avoid OOMing due to excess hints. we need to do this check even for "live" nodes, since we can // still generate hints for those if it's overloaded or simply dead but not yet known-to-be-dead. // The idea is that if we have over maxHintsInProgress hints in flight, this is probably due to // a small number of nodes causing problems, so we should avoid shutting down writes completely to // healthy nodes. Any node with no hintsInProgress is considered healthy. if (StorageMetrics.totalHintsInProgress.getCount() > maxHintsInProgress && (getHintsInProgressFor(destination).get() > 0 && shouldHint(destination))) { throw new OverloadedException("Too many in flight hints: " + StorageMetrics.totalHintsInProgress.getCount() + " destination: " + destination + " destination hints: " + getHintsInProgressFor(destination).get()); } } private static void sendMessagesToNonlocalDC(MessageOut<? extends IMutation> message, Collection<InetAddress> targets, AbstractWriteResponseHandler<IMutation> handler) { Iterator<InetAddress> iter = targets.iterator(); InetAddress target = iter.next(); // Add the other destinations of the same message as a FORWARD_HEADER entry try(DataOutputBuffer out = new DataOutputBuffer()) { out.writeInt(targets.size() - 1); while (iter.hasNext()) { InetAddress destination = iter.next(); CompactEndpointSerializationHelper.serialize(destination, out); int id = MessagingService.instance().addCallback(handler, message, destination, message.getTimeout(), handler.consistencyLevel, true); out.writeInt(id); logger.trace("Adding FWD message to {}@{}", id, destination); } message = message.withParameter(Mutation.FORWARD_TO, out.getData()); // send the combined message + forward headers int id = MessagingService.instance().sendRR(message, target, handler, true); logger.trace("Sending message to {}@{}", id, target); } catch (IOException e) { // DataOutputBuffer is in-memory, doesn't throw IOException throw new AssertionError(e); } } private static void performLocally(Stage stage, final Runnable runnable) { StageManager.getStage(stage).maybeExecuteImmediately(new LocalMutationRunnable() { public void runMayThrow() { try { runnable.run(); } catch (Exception ex) { logger.error("Failed to apply mutation locally : {}", ex); } } @Override protected Verb verb() { return MessagingService.Verb.MUTATION; } }); } private static void performLocally(Stage stage, Optional<IMutation> mutation, final Runnable runnable, final IAsyncCallbackWithFailure<?> handler) { StageManager.getStage(stage).maybeExecuteImmediately(new LocalMutationRunnable(mutation) { public void runMayThrow() { try { runnable.run(); handler.response(null); } catch (Exception ex) { if (!(ex instanceof WriteTimeoutException)) logger.error("Failed to apply mutation locally : {}", ex); handler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.UNKNOWN); } } @Override protected Verb verb() { return MessagingService.Verb.MUTATION; } }); } /** * Handle counter mutation on the coordinator host. * * A counter mutation needs to first be applied to a replica (that we'll call the leader for the mutation) before being * replicated to the other endpoint. To achieve so, there is two case: * 1) the coordinator host is a replica: we proceed to applying the update locally and replicate throug * applyCounterMutationOnCoordinator * 2) the coordinator is not a replica: we forward the (counter)mutation to a chosen replica (that will proceed through * applyCounterMutationOnLeader upon receive) and wait for its acknowledgment. * * Implementation note: We check if we can fulfill the CL on the coordinator host even if he is not a replica to allow * quicker response and because the WriteResponseHandlers don't make it easy to send back an error. We also always gather * the write latencies at the coordinator node to make gathering point similar to the case of standard writes. */ public static AbstractWriteResponseHandler<IMutation> mutateCounter(CounterMutation cm, String localDataCenter, long queryStartNanoTime) throws UnavailableException, OverloadedException { InetAddress endpoint = findSuitableEndpoint(cm.getKeyspaceName(), cm.key(), localDataCenter, cm.consistency()); if (endpoint.equals(FBUtilities.getBroadcastAddress())) { return applyCounterMutationOnCoordinator(cm, localDataCenter, queryStartNanoTime); } else { // Exit now if we can't fulfill the CL here instead of forwarding to the leader replica String keyspaceName = cm.getKeyspaceName(); AbstractReplicationStrategy rs = Keyspace.open(keyspaceName).getReplicationStrategy(); Token tk = cm.key().getToken(); List<InetAddress> naturalEndpoints = StorageService.instance.getNaturalEndpoints(keyspaceName, tk); Collection<InetAddress> pendingEndpoints = StorageService.instance.getTokenMetadata().pendingEndpointsFor(tk, keyspaceName); rs.getWriteResponseHandler(naturalEndpoints, pendingEndpoints, cm.consistency(), null, WriteType.COUNTER, queryStartNanoTime).assureSufficientLiveNodes(); // Forward the actual update to the chosen leader replica AbstractWriteResponseHandler<IMutation> responseHandler = new WriteResponseHandler<>(endpoint, WriteType.COUNTER, queryStartNanoTime); Tracing.trace("Enqueuing counter update to {}", endpoint); MessagingService.instance().sendRR(cm.makeMutationMessage(), endpoint, responseHandler, false); return responseHandler; } } /** * Find a suitable replica as leader for counter update. * For now, we pick a random replica in the local DC (or ask the snitch if * there is no replica alive in the local DC). * TODO: if we track the latency of the counter writes (which makes sense * contrarily to standard writes since there is a read involved), we could * trust the dynamic snitch entirely, which may be a better solution. It * is unclear we want to mix those latencies with read latencies, so this * may be a bit involved. */ private static InetAddress findSuitableEndpoint(String keyspaceName, DecoratedKey key, String localDataCenter, ConsistencyLevel cl) throws UnavailableException { Keyspace keyspace = Keyspace.open(keyspaceName); IEndpointSnitch snitch = DatabaseDescriptor.getEndpointSnitch(); List<InetAddress> endpoints = StorageService.instance.getLiveNaturalEndpoints(keyspace, key); if (endpoints.isEmpty()) // TODO have a way to compute the consistency level throw new UnavailableException(cl, cl.blockFor(keyspace), 0); List<InetAddress> localEndpoints = new ArrayList<InetAddress>(); for (InetAddress endpoint : endpoints) { if (snitch.getDatacenter(endpoint).equals(localDataCenter)) localEndpoints.add(endpoint); } if (localEndpoints.isEmpty()) { // No endpoint in local DC, pick the closest endpoint according to the snitch snitch.sortByProximity(FBUtilities.getBroadcastAddress(), endpoints); return endpoints.get(0); } else { return localEndpoints.get(ThreadLocalRandom.current().nextInt(localEndpoints.size())); } } // Must be called on a replica of the mutation. This replica becomes the // leader of this mutation. public static AbstractWriteResponseHandler<IMutation> applyCounterMutationOnLeader(CounterMutation cm, String localDataCenter, Runnable callback, long queryStartNanoTime) throws UnavailableException, OverloadedException { return performWrite(cm, cm.consistency(), localDataCenter, counterWritePerformer, callback, WriteType.COUNTER, queryStartNanoTime); } // Same as applyCounterMutationOnLeader but must with the difference that it use the MUTATION stage to execute the write (while // applyCounterMutationOnLeader assumes it is on the MUTATION stage already) public static AbstractWriteResponseHandler<IMutation> applyCounterMutationOnCoordinator(CounterMutation cm, String localDataCenter, long queryStartNanoTime) throws UnavailableException, OverloadedException { return performWrite(cm, cm.consistency(), localDataCenter, counterWriteOnCoordinatorPerformer, null, WriteType.COUNTER, queryStartNanoTime); } private static Runnable counterWriteTask(final IMutation mutation, final Iterable<InetAddress> targets, final AbstractWriteResponseHandler<IMutation> responseHandler, final String localDataCenter) { return new DroppableRunnable(MessagingService.Verb.COUNTER_MUTATION) { @Override public void runMayThrow() throws OverloadedException, WriteTimeoutException { assert mutation instanceof CounterMutation; Mutation result = ((CounterMutation) mutation).applyCounterMutation(); responseHandler.response(null); Set<InetAddress> remotes = Sets.difference(ImmutableSet.copyOf(targets), ImmutableSet.of(FBUtilities.getBroadcastAddress())); if (!remotes.isEmpty()) sendToHintedEndpoints(result, remotes, responseHandler, localDataCenter, Stage.COUNTER_MUTATION); } }; } private static boolean systemKeyspaceQuery(List<? extends ReadCommand> cmds) { for (ReadCommand cmd : cmds) if (!SchemaConstants.isSystemKeyspace(cmd.metadata().keyspace)) return false; return true; } public static RowIterator readOne(SinglePartitionReadCommand command, ConsistencyLevel consistencyLevel, long queryStartNanoTime) throws UnavailableException, IsBootstrappingException, ReadFailureException, ReadTimeoutException, InvalidRequestException { return readOne(command, consistencyLevel, null, queryStartNanoTime); } public static RowIterator readOne(SinglePartitionReadCommand command, ConsistencyLevel consistencyLevel, ClientState state, long queryStartNanoTime) throws UnavailableException, IsBootstrappingException, ReadFailureException, ReadTimeoutException, InvalidRequestException { return PartitionIterators.getOnlyElement(read(SinglePartitionReadCommand.Group.one(command), consistencyLevel, state, queryStartNanoTime), command); } public static PartitionIterator read(SinglePartitionReadCommand.Group group, ConsistencyLevel consistencyLevel, long queryStartNanoTime) throws UnavailableException, IsBootstrappingException, ReadFailureException, ReadTimeoutException, InvalidRequestException { // When using serial CL, the ClientState should be provided assert !consistencyLevel.isSerialConsistency(); return read(group, consistencyLevel, null, queryStartNanoTime); } /** * Performs the actual reading of a row out of the StorageService, fetching * a specific set of column names from a given column family. */ public static PartitionIterator read(SinglePartitionReadCommand.Group group, ConsistencyLevel consistencyLevel, ClientState state, long queryStartNanoTime) throws UnavailableException, IsBootstrappingException, ReadFailureException, ReadTimeoutException, InvalidRequestException { if (StorageService.instance.isBootstrapMode() && !systemKeyspaceQuery(group.commands)) { readMetrics.unavailables.mark(); readMetricsMap.get(consistencyLevel).unavailables.mark(); throw new IsBootstrappingException(); } return consistencyLevel.isSerialConsistency() ? readWithPaxos(group, consistencyLevel, state, queryStartNanoTime) : readRegular(group, consistencyLevel, queryStartNanoTime); } private static PartitionIterator readWithPaxos(SinglePartitionReadCommand.Group group, ConsistencyLevel consistencyLevel, ClientState state, long queryStartNanoTime) throws InvalidRequestException, UnavailableException, ReadFailureException, ReadTimeoutException { assert state != null; if (group.commands.size() > 1) throw new InvalidRequestException("SERIAL/LOCAL_SERIAL consistency may only be requested for one partition at a time"); long start = System.nanoTime(); SinglePartitionReadCommand command = group.commands.get(0); TableMetadata metadata = command.metadata(); DecoratedKey key = command.partitionKey(); PartitionIterator result = null; try { // make sure any in-progress paxos writes are done (i.e., committed to a majority of replicas), before performing a quorum read Pair<List<InetAddress>, Integer> p = getPaxosParticipants(metadata, key, consistencyLevel); List<InetAddress> liveEndpoints = p.left; int requiredParticipants = p.right; // does the work of applying in-progress writes; throws UAE or timeout if it can't final ConsistencyLevel consistencyForCommitOrFetch = consistencyLevel == ConsistencyLevel.LOCAL_SERIAL ? ConsistencyLevel.LOCAL_QUORUM : ConsistencyLevel.QUORUM; try { final Pair<UUID, Integer> pair = beginAndRepairPaxos(start, key, metadata, liveEndpoints, requiredParticipants, consistencyLevel, consistencyForCommitOrFetch, false, state); if (pair.right > 0) casReadMetrics.contention.update(pair.right); } catch (WriteTimeoutException e) { throw new ReadTimeoutException(consistencyLevel, 0, consistencyLevel.blockFor(Keyspace.open(metadata.keyspace)), false); } catch (WriteFailureException e) { throw new ReadFailureException(consistencyLevel, e.received, e.blockFor, false, e.failureReasonByEndpoint); } result = fetchRows(group.commands, consistencyForCommitOrFetch, queryStartNanoTime); } catch (UnavailableException e) { readMetrics.unavailables.mark(); casReadMetrics.unavailables.mark(); readMetricsMap.get(consistencyLevel).unavailables.mark(); throw e; } catch (ReadTimeoutException e) { readMetrics.timeouts.mark(); casReadMetrics.timeouts.mark(); readMetricsMap.get(consistencyLevel).timeouts.mark(); throw e; } catch (ReadFailureException e) { readMetrics.failures.mark(); casReadMetrics.failures.mark(); readMetricsMap.get(consistencyLevel).failures.mark(); throw e; } finally { long latency = System.nanoTime() - start; readMetrics.addNano(latency); casReadMetrics.addNano(latency); readMetricsMap.get(consistencyLevel).addNano(latency); Keyspace.open(metadata.keyspace).getColumnFamilyStore(metadata.name).metric.coordinatorReadLatency.update(latency, TimeUnit.NANOSECONDS); } return result; } @SuppressWarnings("resource") private static PartitionIterator readRegular(SinglePartitionReadCommand.Group group, ConsistencyLevel consistencyLevel, long queryStartNanoTime) throws UnavailableException, ReadFailureException, ReadTimeoutException { long start = System.nanoTime(); try { PartitionIterator result = fetchRows(group.commands, consistencyLevel, queryStartNanoTime); // If we have more than one command, then despite each read command honoring the limit, the total result // might not honor it and so we should enforce it if (group.commands.size() > 1) result = group.limits().filter(result, group.nowInSec()); return result; } catch (UnavailableException e) { readMetrics.unavailables.mark(); readMetricsMap.get(consistencyLevel).unavailables.mark(); throw e; } catch (ReadTimeoutException e) { readMetrics.timeouts.mark(); readMetricsMap.get(consistencyLevel).timeouts.mark(); throw e; } catch (ReadFailureException e) { readMetrics.failures.mark(); readMetricsMap.get(consistencyLevel).failures.mark(); throw e; } finally { long latency = System.nanoTime() - start; readMetrics.addNano(latency); readMetricsMap.get(consistencyLevel).addNano(latency); // TODO avoid giving every command the same latency number. Can fix this in CASSADRA-5329 for (ReadCommand command : group.commands) Keyspace.openAndGetStore(command.metadata()).metric.coordinatorReadLatency.update(latency, TimeUnit.NANOSECONDS); } } /** * This function executes local and remote reads, and blocks for the results: * * 1. Get the replica locations, sorted by response time according to the snitch * 2. Send a data request to the closest replica, and digest requests to either * a) all the replicas, if read repair is enabled * b) the closest R-1 replicas, where R is the number required to satisfy the ConsistencyLevel * 3. Wait for a response from R replicas * 4. If the digests (if any) match the data return the data * 5. else carry out read repair by getting data from all the nodes. */ private static PartitionIterator fetchRows(List<SinglePartitionReadCommand> commands, ConsistencyLevel consistencyLevel, long queryStartNanoTime) throws UnavailableException, ReadFailureException, ReadTimeoutException { int cmdCount = commands.size(); SinglePartitionReadLifecycle[] reads = new SinglePartitionReadLifecycle[cmdCount]; for (int i = 0; i < cmdCount; i++) reads[i] = new SinglePartitionReadLifecycle(commands.get(i), consistencyLevel, queryStartNanoTime); for (int i = 0; i < cmdCount; i++) reads[i].doInitialQueries(); for (int i = 0; i < cmdCount; i++) reads[i].maybeTryAdditionalReplicas(); for (int i = 0; i < cmdCount; i++) reads[i].awaitResultsAndRetryOnDigestMismatch(); for (int i = 0; i < cmdCount; i++) if (!reads[i].isDone()) reads[i].maybeAwaitFullDataRead(); List<PartitionIterator> results = new ArrayList<>(cmdCount); for (int i = 0; i < cmdCount; i++) { assert reads[i].isDone(); results.add(reads[i].getResult()); } return PartitionIterators.concat(results); } private static class SinglePartitionReadLifecycle { private final SinglePartitionReadCommand command; private final AbstractReadExecutor executor; private final ConsistencyLevel consistency; private final long queryStartNanoTime; private PartitionIterator result; private ReadCallback repairHandler; SinglePartitionReadLifecycle(SinglePartitionReadCommand command, ConsistencyLevel consistency, long queryStartNanoTime) { this.command = command; this.executor = AbstractReadExecutor.getReadExecutor(command, consistency, queryStartNanoTime); this.consistency = consistency; this.queryStartNanoTime = queryStartNanoTime; } boolean isDone() { return result != null; } void doInitialQueries() { executor.executeAsync(); } void maybeTryAdditionalReplicas() { executor.maybeTryAdditionalReplicas(); } void awaitResultsAndRetryOnDigestMismatch() throws ReadFailureException, ReadTimeoutException { try { result = executor.get(); } catch (DigestMismatchException ex) { Tracing.trace("Digest mismatch: {}", ex); ReadRepairMetrics.repairedBlocking.mark(); // Do a full data read to resolve the correct response (and repair node that need be) Keyspace keyspace = Keyspace.open(command.metadata().keyspace); DataResolver resolver = new DataResolver(keyspace, command, ConsistencyLevel.ALL, executor.handler.endpoints.size(), queryStartNanoTime); repairHandler = new ReadCallback(resolver, ConsistencyLevel.ALL, executor.getContactedReplicas().size(), command, keyspace, executor.handler.endpoints, queryStartNanoTime); for (InetAddress endpoint : executor.getContactedReplicas()) { Tracing.trace("Enqueuing full data read to {}", endpoint); MessagingService.instance().sendRRWithFailure(command.createMessage(), endpoint, repairHandler); } } } void maybeAwaitFullDataRead() throws ReadTimeoutException { // There wasn't a digest mismatch, we're good if (repairHandler == null) return; // Otherwise, get the result from the full-data read and check that it's not a short read try { result = repairHandler.get(); } catch (DigestMismatchException e) { throw new AssertionError(e); // full data requested from each node here, no digests should be sent } catch (ReadTimeoutException e) { if (Tracing.isTracing()) Tracing.trace("Timed out waiting on digest mismatch repair requests"); else logger.trace("Timed out waiting on digest mismatch repair requests"); // the caught exception here will have CL.ALL from the repair command, // not whatever CL the initial command was at (CASSANDRA-7947) int blockFor = consistency.blockFor(Keyspace.open(command.metadata().keyspace)); throw new ReadTimeoutException(consistency, blockFor-1, blockFor, true); } } PartitionIterator getResult() { assert result != null; return result; } } static class LocalReadRunnable extends DroppableRunnable { private final ReadCommand command; private final ReadCallback handler; private final long start = System.nanoTime(); LocalReadRunnable(ReadCommand command, ReadCallback handler) { super(MessagingService.Verb.READ); this.command = command; this.handler = handler; } protected void runMayThrow() { try { command.setMonitoringTime(constructionTime, false, verb.getTimeout(), DatabaseDescriptor.getSlowQueryTimeout()); ReadResponse response; try (ReadExecutionController executionController = command.executionController(); UnfilteredPartitionIterator iterator = command.executeLocally(executionController)) { response = command.createResponse(iterator); } if (command.complete()) { handler.response(response); } else { MessagingService.instance().incrementDroppedMessages(verb, System.currentTimeMillis() - constructionTime); handler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.UNKNOWN); } MessagingService.instance().addLatency(FBUtilities.getBroadcastAddress(), TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - start)); } catch (Throwable t) { if (t instanceof TombstoneOverwhelmingException) { handler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.READ_TOO_MANY_TOMBSTONES); logger.error(t.getMessage()); } else { handler.onFailure(FBUtilities.getBroadcastAddress(), RequestFailureReason.UNKNOWN); throw t; } } } } public static List<InetAddress> getLiveSortedEndpoints(Keyspace keyspace, ByteBuffer key) { return getLiveSortedEndpoints(keyspace, StorageService.instance.getTokenMetadata().decorateKey(key)); } public static List<InetAddress> getLiveSortedEndpoints(Keyspace keyspace, RingPosition pos) { List<InetAddress> liveEndpoints = StorageService.instance.getLiveNaturalEndpoints(keyspace, pos); DatabaseDescriptor.getEndpointSnitch().sortByProximity(FBUtilities.getBroadcastAddress(), liveEndpoints); return liveEndpoints; } private static List<InetAddress> intersection(List<InetAddress> l1, List<InetAddress> l2) { // Note: we don't use Guava Sets.intersection() for 3 reasons: // 1) retainAll would be inefficient if l1 and l2 are large but in practice both are the replicas for a range and // so will be very small (< RF). In that case, retainAll is in fact more efficient. // 2) we do ultimately need a list so converting everything to sets don't make sense // 3) l1 and l2 are sorted by proximity. The use of retainAll maintain that sorting in the result, while using sets wouldn't. List<InetAddress> inter = new ArrayList<InetAddress>(l1); inter.retainAll(l2); return inter; } /** * Estimate the number of result rows per range in the ring based on our local data. * <p> * This assumes that ranges are uniformly distributed across the cluster and * that the queried data is also uniformly distributed. */ private static float estimateResultsPerRange(PartitionRangeReadCommand command, Keyspace keyspace) { ColumnFamilyStore cfs = keyspace.getColumnFamilyStore(command.metadata().id); Index index = command.getIndex(cfs); float maxExpectedResults = index == null ? command.limits().estimateTotalResults(cfs) : index.getEstimatedResultRows(); // adjust maxExpectedResults by the number of tokens this node has and the replication factor for this ks return (maxExpectedResults / DatabaseDescriptor.getNumTokens()) / keyspace.getReplicationStrategy().getReplicationFactor(); } private static class RangeForQuery { public final AbstractBounds<PartitionPosition> range; public final List<InetAddress> liveEndpoints; public final List<InetAddress> filteredEndpoints; public RangeForQuery(AbstractBounds<PartitionPosition> range, List<InetAddress> liveEndpoints, List<InetAddress> filteredEndpoints) { this.range = range; this.liveEndpoints = liveEndpoints; this.filteredEndpoints = filteredEndpoints; } } private static class RangeIterator extends AbstractIterator<RangeForQuery> { private final Keyspace keyspace; private final ConsistencyLevel consistency; private final Iterator<? extends AbstractBounds<PartitionPosition>> ranges; private final int rangeCount; public RangeIterator(PartitionRangeReadCommand command, Keyspace keyspace, ConsistencyLevel consistency) { this.keyspace = keyspace; this.consistency = consistency; List<? extends AbstractBounds<PartitionPosition>> l = keyspace.getReplicationStrategy() instanceof LocalStrategy ? command.dataRange().keyRange().unwrap() : getRestrictedRanges(command.dataRange().keyRange()); this.ranges = l.iterator(); this.rangeCount = l.size(); } public int rangeCount() { return rangeCount; } protected RangeForQuery computeNext() { if (!ranges.hasNext()) return endOfData(); AbstractBounds<PartitionPosition> range = ranges.next(); List<InetAddress> liveEndpoints = getLiveSortedEndpoints(keyspace, range.right); return new RangeForQuery(range, liveEndpoints, consistency.filterForQuery(keyspace, liveEndpoints)); } } private static class RangeMerger extends AbstractIterator<RangeForQuery> { private final Keyspace keyspace; private final ConsistencyLevel consistency; private final PeekingIterator<RangeForQuery> ranges; private RangeMerger(Iterator<RangeForQuery> iterator, Keyspace keyspace, ConsistencyLevel consistency) { this.keyspace = keyspace; this.consistency = consistency; this.ranges = Iterators.peekingIterator(iterator); } protected RangeForQuery computeNext() { if (!ranges.hasNext()) return endOfData(); RangeForQuery current = ranges.next(); // getRestrictedRange has broken the queried range into per-[vnode] token ranges, but this doesn't take // the replication factor into account. If the intersection of live endpoints for 2 consecutive ranges // still meets the CL requirements, then we can merge both ranges into the same RangeSliceCommand. while (ranges.hasNext()) { // If the current range right is the min token, we should stop merging because CFS.getRangeSlice // don't know how to deal with a wrapping range. // Note: it would be slightly more efficient to have CFS.getRangeSlice on the destination nodes unwraps // the range if necessary and deal with it. However, we can't start sending wrapped range without breaking // wire compatibility, so It's likely easier not to bother; if (current.range.right.isMinimum()) break; RangeForQuery next = ranges.peek(); List<InetAddress> merged = intersection(current.liveEndpoints, next.liveEndpoints); // Check if there is enough endpoint for the merge to be possible. if (!consistency.isSufficientLiveNodes(keyspace, merged)) break; List<InetAddress> filteredMerged = consistency.filterForQuery(keyspace, merged); // Estimate whether merging will be a win or not if (!DatabaseDescriptor.getEndpointSnitch().isWorthMergingForRangeQuery(filteredMerged, current.filteredEndpoints, next.filteredEndpoints)) break; // If we get there, merge this range and the next one current = new RangeForQuery(current.range.withNewRight(next.range.right), merged, filteredMerged); ranges.next(); // consume the range we just merged since we've only peeked so far } return current; } } private static class SingleRangeResponse extends AbstractIterator<RowIterator> implements PartitionIterator { private final ReadCallback handler; private PartitionIterator result; private SingleRangeResponse(ReadCallback handler) { this.handler = handler; } private void waitForResponse() throws ReadTimeoutException { if (result != null) return; try { result = handler.get(); } catch (DigestMismatchException e) { throw new AssertionError(e); // no digests in range slices yet } } protected RowIterator computeNext() { waitForResponse(); return result.hasNext() ? result.next() : endOfData(); } public void close() { if (result != null) result.close(); } } private static class RangeCommandIterator extends AbstractIterator<RowIterator> implements PartitionIterator { private final Iterator<RangeForQuery> ranges; private final int totalRangeCount; private final PartitionRangeReadCommand command; private final Keyspace keyspace; private final ConsistencyLevel consistency; private final long startTime; private final long queryStartNanoTime; private DataLimits.Counter counter; private PartitionIterator sentQueryIterator; private int concurrencyFactor; // The two following "metric" are maintained to improve the concurrencyFactor // when it was not good enough initially. private int liveReturned; private int rangesQueried; public RangeCommandIterator(RangeIterator ranges, PartitionRangeReadCommand command, int concurrencyFactor, Keyspace keyspace, ConsistencyLevel consistency, long queryStartNanoTime) { this.command = command; this.concurrencyFactor = concurrencyFactor; this.startTime = System.nanoTime(); this.ranges = new RangeMerger(ranges, keyspace, consistency); this.totalRangeCount = ranges.rangeCount(); this.consistency = consistency; this.keyspace = keyspace; this.queryStartNanoTime = queryStartNanoTime; } public RowIterator computeNext() { try { while (sentQueryIterator == null || !sentQueryIterator.hasNext()) { // If we don't have more range to handle, we're done if (!ranges.hasNext()) return endOfData(); // else, sends the next batch of concurrent queries (after having close the previous iterator) if (sentQueryIterator != null) { liveReturned += counter.counted(); sentQueryIterator.close(); // It's not the first batch of queries and we're not done, so we we can use what has been // returned so far to improve our rows-per-range estimate and update the concurrency accordingly updateConcurrencyFactor(); } sentQueryIterator = sendNextRequests(); } return sentQueryIterator.next(); } catch (UnavailableException e) { rangeMetrics.unavailables.mark(); throw e; } catch (ReadTimeoutException e) { rangeMetrics.timeouts.mark(); throw e; } catch (ReadFailureException e) { rangeMetrics.failures.mark(); throw e; } } private void updateConcurrencyFactor() { if (liveReturned == 0) { // we haven't actually gotten any results, so query all remaining ranges at once concurrencyFactor = totalRangeCount - rangesQueried; return; } // Otherwise, compute how many rows per range we got on average and pick a concurrency factor // that should allow us to fetch all remaining rows with the next batch of (concurrent) queries. int remainingRows = command.limits().count() - liveReturned; float rowsPerRange = (float)liveReturned / (float)rangesQueried; concurrencyFactor = Math.max(1, Math.min(totalRangeCount - rangesQueried, Math.round(remainingRows / rowsPerRange))); logger.trace("Didn't get enough response rows; actual rows per range: {}; remaining rows: {}, new concurrent requests: {}", rowsPerRange, remainingRows, concurrencyFactor); } /** * Queries the provided sub-range. * * @param toQuery the subRange to query. * @param isFirst in the case where multiple queries are sent in parallel, whether that's the first query on * that batch or not. The reason it matters is that whe paging queries, the command (more specifically the * {@code DataLimits}) may have "state" information and that state may only be valid for the first query (in * that it's the query that "continues" whatever we're previously queried). */ private SingleRangeResponse query(RangeForQuery toQuery, boolean isFirst) { PartitionRangeReadCommand rangeCommand = command.forSubRange(toQuery.range, isFirst); DataResolver resolver = new DataResolver(keyspace, rangeCommand, consistency, toQuery.filteredEndpoints.size(), queryStartNanoTime); int blockFor = consistency.blockFor(keyspace); int minResponses = Math.min(toQuery.filteredEndpoints.size(), blockFor); List<InetAddress> minimalEndpoints = toQuery.filteredEndpoints.subList(0, minResponses); ReadCallback handler = new ReadCallback(resolver, consistency, rangeCommand, minimalEndpoints, queryStartNanoTime); handler.assureSufficientLiveNodes(); if (toQuery.filteredEndpoints.size() == 1 && canDoLocalRequest(toQuery.filteredEndpoints.get(0))) { StageManager.getStage(Stage.READ).execute(new LocalReadRunnable(rangeCommand, handler)); } else { for (InetAddress endpoint : toQuery.filteredEndpoints) { Tracing.trace("Enqueuing request to {}", endpoint); MessagingService.instance().sendRRWithFailure(rangeCommand.createMessage(), endpoint, handler); } } return new SingleRangeResponse(handler); } private PartitionIterator sendNextRequests() { List<PartitionIterator> concurrentQueries = new ArrayList<>(concurrencyFactor); for (int i = 0; i < concurrencyFactor && ranges.hasNext(); i++) { concurrentQueries.add(query(ranges.next(), i == 0)); ++rangesQueried; } Tracing.trace("Submitted {} concurrent range requests", concurrentQueries.size()); // We want to count the results for the sake of updating the concurrency factor (see updateConcurrencyFactor) but we don't want to // enforce any particular limit at this point (this could break code than rely on postReconciliationProcessing), hence the DataLimits.NONE. counter = DataLimits.NONE.newCounter(command.nowInSec(), true); return counter.applyTo(PartitionIterators.concat(concurrentQueries)); } public void close() { try { if (sentQueryIterator != null) sentQueryIterator.close(); } finally { long latency = System.nanoTime() - startTime; rangeMetrics.addNano(latency); Keyspace.openAndGetStore(command.metadata()).metric.coordinatorScanLatency.update(latency, TimeUnit.NANOSECONDS); } } } @SuppressWarnings("resource") public static PartitionIterator getRangeSlice(PartitionRangeReadCommand command, ConsistencyLevel consistencyLevel, long queryStartNanoTime) { Tracing.trace("Computing ranges to query"); Keyspace keyspace = Keyspace.open(command.metadata().keyspace); RangeIterator ranges = new RangeIterator(command, keyspace, consistencyLevel); // our estimate of how many result rows there will be per-range float resultsPerRange = estimateResultsPerRange(command, keyspace); // underestimate how many rows we will get per-range in order to increase the likelihood that we'll // fetch enough rows in the first round resultsPerRange -= resultsPerRange * CONCURRENT_SUBREQUESTS_MARGIN; int concurrencyFactor = resultsPerRange == 0.0 ? 1 : Math.max(1, Math.min(ranges.rangeCount(), (int) Math.ceil(command.limits().count() / resultsPerRange))); logger.trace("Estimated result rows per range: {}; requested rows: {}, ranges.size(): {}; concurrent range requests: {}", resultsPerRange, command.limits().count(), ranges.rangeCount(), concurrencyFactor); Tracing.trace("Submitting range requests on {} ranges with a concurrency of {} ({} rows per range expected)", ranges.rangeCount(), concurrencyFactor, resultsPerRange); // Note that in general, a RangeCommandIterator will honor the command limit for each range, but will not enforce it globally. return command.limits().filter(command.postReconciliationProcessing(new RangeCommandIterator(ranges, command, concurrencyFactor, keyspace, consistencyLevel, queryStartNanoTime)), command.nowInSec()); } public Map<String, List<String>> getSchemaVersions() { return describeSchemaVersions(); } /** * initiate a request/response session with each live node to check whether or not everybody is using the same * migration id. This is useful for determining if a schema change has propagated through the cluster. Disagreement * is assumed if any node fails to respond. */ public static Map<String, List<String>> describeSchemaVersions() { final String myVersion = Schema.instance.getVersion().toString(); final Map<InetAddress, UUID> versions = new ConcurrentHashMap<InetAddress, UUID>(); final Set<InetAddress> liveHosts = Gossiper.instance.getLiveMembers(); final CountDownLatch latch = new CountDownLatch(liveHosts.size()); IAsyncCallback<UUID> cb = new IAsyncCallback<UUID>() { public void response(MessageIn<UUID> message) { // record the response from the remote node. versions.put(message.from, message.payload); latch.countDown(); } public boolean isLatencyForSnitch() { return false; } }; // an empty message acts as a request to the SchemaVersionVerbHandler. MessageOut message = new MessageOut(MessagingService.Verb.SCHEMA_CHECK); for (InetAddress endpoint : liveHosts) MessagingService.instance().sendRR(message, endpoint, cb); try { // wait for as long as possible. timeout-1s if possible. latch.await(DatabaseDescriptor.getRpcTimeout(), TimeUnit.MILLISECONDS); } catch (InterruptedException ex) { throw new AssertionError("This latch shouldn't have been interrupted."); } // maps versions to hosts that are on that version. Map<String, List<String>> results = new HashMap<String, List<String>>(); Iterable<InetAddress> allHosts = Iterables.concat(Gossiper.instance.getLiveMembers(), Gossiper.instance.getUnreachableMembers()); for (InetAddress host : allHosts) { UUID version = versions.get(host); String stringVersion = version == null ? UNREACHABLE : version.toString(); List<String> hosts = results.get(stringVersion); if (hosts == null) { hosts = new ArrayList<String>(); results.put(stringVersion, hosts); } hosts.add(host.getHostAddress()); } // we're done: the results map is ready to return to the client. the rest is just debug logging: if (results.get(UNREACHABLE) != null) logger.debug("Hosts not in agreement. Didn't get a response from everybody: {}", StringUtils.join(results.get(UNREACHABLE), ",")); for (Map.Entry<String, List<String>> entry : results.entrySet()) { // check for version disagreement. log the hosts that don't agree. if (entry.getKey().equals(UNREACHABLE) || entry.getKey().equals(myVersion)) continue; for (String host : entry.getValue()) logger.debug("{} disagrees ({})", host, entry.getKey()); } if (results.size() == 1) logger.debug("Schemas are in agreement."); return results; } /** * Compute all ranges we're going to query, in sorted order. Nodes can be replica destinations for many ranges, * so we need to restrict each scan to the specific range we want, or else we'd get duplicate results. */ static <T extends RingPosition<T>> List<AbstractBounds<T>> getRestrictedRanges(final AbstractBounds<T> queryRange) { // special case for bounds containing exactly 1 (non-minimum) token if (queryRange instanceof Bounds && queryRange.left.equals(queryRange.right) && !queryRange.left.isMinimum()) { return Collections.singletonList(queryRange); } TokenMetadata tokenMetadata = StorageService.instance.getTokenMetadata(); List<AbstractBounds<T>> ranges = new ArrayList<AbstractBounds<T>>(); // divide the queryRange into pieces delimited by the ring and minimum tokens Iterator<Token> ringIter = TokenMetadata.ringIterator(tokenMetadata.sortedTokens(), queryRange.left.getToken(), true); AbstractBounds<T> remainder = queryRange; while (ringIter.hasNext()) { /* * remainder can be a range/bounds of token _or_ keys and we want to split it with a token: * - if remainder is tokens, then we'll just split using the provided token. * - if remainder is keys, we want to split using token.upperBoundKey. For instance, if remainder * is [DK(10, 'foo'), DK(20, 'bar')], and we have 3 nodes with tokens 0, 15, 30. We want to * split remainder to A=[DK(10, 'foo'), 15] and B=(15, DK(20, 'bar')]. But since we can't mix * tokens and keys at the same time in a range, we uses 15.upperBoundKey() to have A include all * keys having 15 as token and B include none of those (since that is what our node owns). * asSplitValue() abstracts that choice. */ Token upperBoundToken = ringIter.next(); T upperBound = (T)upperBoundToken.upperBound(queryRange.left.getClass()); if (!remainder.left.equals(upperBound) && !remainder.contains(upperBound)) // no more splits break; Pair<AbstractBounds<T>,AbstractBounds<T>> splits = remainder.split(upperBound); if (splits == null) continue; ranges.add(splits.left); remainder = splits.right; } ranges.add(remainder); return ranges; } public boolean getHintedHandoffEnabled() { return DatabaseDescriptor.hintedHandoffEnabled(); } public void setHintedHandoffEnabled(boolean b) { synchronized (StorageService.instance) { if (b) StorageService.instance.checkServiceAllowedToStart("hinted handoff"); DatabaseDescriptor.setHintedHandoffEnabled(b); } } public void enableHintsForDC(String dc) { DatabaseDescriptor.enableHintsForDC(dc); } public void disableHintsForDC(String dc) { DatabaseDescriptor.disableHintsForDC(dc); } public Set<String> getHintedHandoffDisabledDCs() { return DatabaseDescriptor.hintedHandoffDisabledDCs(); } public int getMaxHintWindow() { return DatabaseDescriptor.getMaxHintWindow(); } public void setMaxHintWindow(int ms) { DatabaseDescriptor.setMaxHintWindow(ms); } public static boolean shouldHint(InetAddress ep) { if (DatabaseDescriptor.hintedHandoffEnabled()) { Set<String> disabledDCs = DatabaseDescriptor.hintedHandoffDisabledDCs(); if (!disabledDCs.isEmpty()) { final String dc = DatabaseDescriptor.getEndpointSnitch().getDatacenter(ep); if (disabledDCs.contains(dc)) { Tracing.trace("Not hinting {} since its data center {} has been disabled {}", ep, dc, disabledDCs); return false; } } boolean hintWindowExpired = Gossiper.instance.getEndpointDowntime(ep) > DatabaseDescriptor.getMaxHintWindow(); if (hintWindowExpired) { HintsService.instance.metrics.incrPastWindow(ep); Tracing.trace("Not hinting {} which has been down {} ms", ep, Gossiper.instance.getEndpointDowntime(ep)); } return !hintWindowExpired; } else { return false; } } /** * Performs the truncate operatoin, which effectively deletes all data from * the column family cfname * @param keyspace * @param cfname * @throws UnavailableException If some of the hosts in the ring are down. * @throws TimeoutException */ public static void truncateBlocking(String keyspace, String cfname) throws UnavailableException, TimeoutException { logger.debug("Starting a blocking truncate operation on keyspace {}, CF {}", keyspace, cfname); if (isAnyStorageHostDown()) { logger.info("Cannot perform truncate, some hosts are down"); // Since the truncate operation is so aggressive and is typically only // invoked by an admin, for simplicity we require that all nodes are up // to perform the operation. int liveMembers = Gossiper.instance.getLiveMembers().size(); throw new UnavailableException(ConsistencyLevel.ALL, liveMembers + Gossiper.instance.getUnreachableMembers().size(), liveMembers); } Set<InetAddress> allEndpoints = StorageService.instance.getLiveRingMembers(true); int blockFor = allEndpoints.size(); final TruncateResponseHandler responseHandler = new TruncateResponseHandler(blockFor); // Send out the truncate calls and track the responses with the callbacks. Tracing.trace("Enqueuing truncate messages to hosts {}", allEndpoints); final Truncation truncation = new Truncation(keyspace, cfname); MessageOut<Truncation> message = truncation.createMessage(); for (InetAddress endpoint : allEndpoints) MessagingService.instance().sendRR(message, endpoint, responseHandler); // Wait for all try { responseHandler.get(); } catch (TimeoutException e) { Tracing.trace("Timed out"); throw e; } } /** * Asks the gossiper if there are any nodes that are currently down. * @return true if the gossiper thinks all nodes are up. */ private static boolean isAnyStorageHostDown() { return !Gossiper.instance.getUnreachableTokenOwners().isEmpty(); } public interface WritePerformer { public void apply(IMutation mutation, Iterable<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler, String localDataCenter, ConsistencyLevel consistencyLevel) throws OverloadedException; } /** * This class captures metrics for views writes. */ private static class ViewWriteMetricsWrapped extends BatchlogResponseHandler<IMutation> { public ViewWriteMetricsWrapped(AbstractWriteResponseHandler<IMutation> writeHandler, int i, BatchlogCleanup cleanup, long queryStartNanoTime) { super(writeHandler, i, cleanup, queryStartNanoTime); viewWriteMetrics.viewReplicasAttempted.inc(totalEndpoints()); } public void response(MessageIn<IMutation> msg) { super.response(msg); viewWriteMetrics.viewReplicasSuccess.inc(); } } /** * A Runnable that aborts if it doesn't start running before it times out */ private static abstract class DroppableRunnable implements Runnable { final long constructionTime; final MessagingService.Verb verb; public DroppableRunnable(MessagingService.Verb verb) { this.constructionTime = System.currentTimeMillis(); this.verb = verb; } public final void run() { long timeTaken = System.currentTimeMillis() - constructionTime; if (timeTaken > verb.getTimeout()) { MessagingService.instance().incrementDroppedMessages(verb, timeTaken); return; } try { runMayThrow(); } catch (Exception e) { throw new RuntimeException(e); } } abstract protected void runMayThrow() throws Exception; } /** * Like DroppableRunnable, but if it aborts, it will rerun (on the mutation stage) after * marking itself as a hint in progress so that the hint backpressure mechanism can function. */ private static abstract class LocalMutationRunnable implements Runnable { private final long constructionTime = System.currentTimeMillis(); private final Optional<IMutation> mutationOpt; public LocalMutationRunnable(Optional<IMutation> mutationOpt) { this.mutationOpt = mutationOpt; } public LocalMutationRunnable() { this.mutationOpt = Optional.empty(); } public final void run() { final MessagingService.Verb verb = verb(); long mutationTimeout = verb.getTimeout(); long timeTaken = System.currentTimeMillis() - constructionTime; if (timeTaken > mutationTimeout) { if (MessagingService.DROPPABLE_VERBS.contains(verb)) MessagingService.instance().incrementDroppedMutations(mutationOpt, timeTaken); HintRunnable runnable = new HintRunnable(Collections.singleton(FBUtilities.getBroadcastAddress())) { protected void runMayThrow() throws Exception { LocalMutationRunnable.this.runMayThrow(); } }; submitHint(runnable); return; } try { runMayThrow(); } catch (Exception e) { throw new RuntimeException(e); } } abstract protected MessagingService.Verb verb(); abstract protected void runMayThrow() throws Exception; } /** * HintRunnable will decrease totalHintsInProgress and targetHints when finished. * It is the caller's responsibility to increment them initially. */ private abstract static class HintRunnable implements Runnable { public final Collection<InetAddress> targets; protected HintRunnable(Collection<InetAddress> targets) { this.targets = targets; } public void run() { try { runMayThrow(); } catch (Exception e) { throw new RuntimeException(e); } finally { StorageMetrics.totalHintsInProgress.dec(targets.size()); for (InetAddress target : targets) getHintsInProgressFor(target).decrementAndGet(); } } abstract protected void runMayThrow() throws Exception; } public long getTotalHints() { return StorageMetrics.totalHints.getCount(); } public int getMaxHintsInProgress() { return maxHintsInProgress; } public void setMaxHintsInProgress(int qs) { maxHintsInProgress = qs; } public int getHintsInProgress() { return (int) StorageMetrics.totalHintsInProgress.getCount(); } public void verifyNoHintsInProgress() { if (getHintsInProgress() > 0) logger.warn("Some hints were not written before shutdown. This is not supposed to happen. You should (a) run repair, and (b) file a bug report"); } private static AtomicInteger getHintsInProgressFor(InetAddress destination) { try { return hintsInProgress.load(destination); } catch (Exception e) { throw new AssertionError(e); } } public static Future<Void> submitHint(Mutation mutation, InetAddress target, AbstractWriteResponseHandler<IMutation> responseHandler) { return submitHint(mutation, Collections.singleton(target), responseHandler); } public static Future<Void> submitHint(Mutation mutation, Collection<InetAddress> targets, AbstractWriteResponseHandler<IMutation> responseHandler) { HintRunnable runnable = new HintRunnable(targets) { public void runMayThrow() { Set<InetAddress> validTargets = new HashSet<>(targets.size()); Set<UUID> hostIds = new HashSet<>(targets.size()); for (InetAddress target : targets) { UUID hostId = StorageService.instance.getHostIdForEndpoint(target); if (hostId != null) { hostIds.add(hostId); validTargets.add(target); } else logger.debug("Discarding hint for endpoint not part of ring: {}", target); } logger.trace("Adding hints for {}", validTargets); HintsService.instance.write(hostIds, Hint.create(mutation, System.currentTimeMillis())); validTargets.forEach(HintsService.instance.metrics::incrCreatedHints); // Notify the handler only for CL == ANY if (responseHandler != null && responseHandler.consistencyLevel == ConsistencyLevel.ANY) responseHandler.response(null); } }; return submitHint(runnable); } private static Future<Void> submitHint(HintRunnable runnable) { StorageMetrics.totalHintsInProgress.inc(runnable.targets.size()); for (InetAddress target : runnable.targets) getHintsInProgressFor(target).incrementAndGet(); return (Future<Void>) StageManager.getStage(Stage.MUTATION).submit(runnable); } public Long getRpcTimeout() { return DatabaseDescriptor.getRpcTimeout(); } public void setRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setRpcTimeout(timeoutInMillis); } public Long getReadRpcTimeout() { return DatabaseDescriptor.getReadRpcTimeout(); } public void setReadRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setReadRpcTimeout(timeoutInMillis); } public Long getWriteRpcTimeout() { return DatabaseDescriptor.getWriteRpcTimeout(); } public void setWriteRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setWriteRpcTimeout(timeoutInMillis); } public Long getCounterWriteRpcTimeout() { return DatabaseDescriptor.getCounterWriteRpcTimeout(); } public void setCounterWriteRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setCounterWriteRpcTimeout(timeoutInMillis); } public Long getCasContentionTimeout() { return DatabaseDescriptor.getCasContentionTimeout(); } public void setCasContentionTimeout(Long timeoutInMillis) { DatabaseDescriptor.setCasContentionTimeout(timeoutInMillis); } public Long getRangeRpcTimeout() { return DatabaseDescriptor.getRangeRpcTimeout(); } public void setRangeRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setRangeRpcTimeout(timeoutInMillis); } public Long getTruncateRpcTimeout() { return DatabaseDescriptor.getTruncateRpcTimeout(); } public void setTruncateRpcTimeout(Long timeoutInMillis) { DatabaseDescriptor.setTruncateRpcTimeout(timeoutInMillis); } public Long getNativeTransportMaxConcurrentConnections() { return DatabaseDescriptor.getNativeTransportMaxConcurrentConnections(); } public void setNativeTransportMaxConcurrentConnections(Long nativeTransportMaxConcurrentConnections) { DatabaseDescriptor.setNativeTransportMaxConcurrentConnections(nativeTransportMaxConcurrentConnections); } public Long getNativeTransportMaxConcurrentConnectionsPerIp() { return DatabaseDescriptor.getNativeTransportMaxConcurrentConnectionsPerIp(); } public void setNativeTransportMaxConcurrentConnectionsPerIp(Long nativeTransportMaxConcurrentConnections) { DatabaseDescriptor.setNativeTransportMaxConcurrentConnectionsPerIp(nativeTransportMaxConcurrentConnections); } public void reloadTriggerClasses() { TriggerExecutor.instance.reloadClasses(); } public long getReadRepairAttempted() { return ReadRepairMetrics.attempted.getCount(); } public long getReadRepairRepairedBlocking() { return ReadRepairMetrics.repairedBlocking.getCount(); } public long getReadRepairRepairedBackground() { return ReadRepairMetrics.repairedBackground.getCount(); } public int getNumberOfTables() { return Schema.instance.getNumberOfTables(); } public String getIdealConsistencyLevel() { return DatabaseDescriptor.getIdealConsistencyLevel().toString(); } public String setIdealConsistencyLevel(String cl) { ConsistencyLevel original = DatabaseDescriptor.getIdealConsistencyLevel(); ConsistencyLevel newCL = ConsistencyLevel.valueOf(cl.trim().toUpperCase()); DatabaseDescriptor.setIdealConsistencyLevel(newCL); return String.format("Updating ideal consistency level new value: %s old value %s", newCL, original.toString()); } public int getOtcBacklogExpirationInterval() { return DatabaseDescriptor.getOtcBacklogExpirationInterval(); } public void setOtcBacklogExpirationInterval(int intervalInMillis) { DatabaseDescriptor.setOtcBacklogExpirationInterval(intervalInMillis); } }