opendaylight/md-sal/sal-akka-raft/src/main/java/org/opendaylight/controller/cluster/raft/SnapshotManager.java

   1 /*
   2  * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.cluster.raft;
   9
  10 import akka.persistence.SnapshotSelectionCriteria;
  11 import com.google.common.annotations.VisibleForTesting;
  12 import com.google.common.io.ByteSource;
  13 import java.io.IOException;
  14 import java.io.OutputStream;
  15 import java.util.List;
  16 import java.util.Optional;
  17 import java.util.function.Consumer;
  18 import org.eclipse.jdt.annotation.NonNull;
  19 import org.opendaylight.controller.cluster.io.FileBackedOutputStream;
  20 import org.opendaylight.controller.cluster.raft.base.messages.ApplySnapshot;
  21 import org.opendaylight.controller.cluster.raft.base.messages.CaptureSnapshot;
  22 import org.opendaylight.controller.cluster.raft.base.messages.SendInstallSnapshot;
  23 import org.opendaylight.controller.cluster.raft.base.messages.SnapshotComplete;
  24 import org.opendaylight.controller.cluster.raft.behaviors.RaftActorBehavior;
  25 import org.opendaylight.controller.cluster.raft.persisted.EmptyState;
  26 import org.opendaylight.controller.cluster.raft.persisted.Snapshot;
  27 import org.slf4j.Logger;
  28
  29 /**
  30  * Manages the capturing of snapshots for a RaftActor.
  31  *
  32  * @author Moiz Raja
  33  * @author Thomas Pantelis
  34  */
  35 public class SnapshotManager implements SnapshotState {
  36
  37     @SuppressWarnings("checkstyle:MemberName")
  38     private final SnapshotState IDLE = new Idle();
  39
  40     @SuppressWarnings({"checkstyle:MemberName", "checkstyle:AbbreviationAsWordInName"})
  41     private final SnapshotState PERSISTING = new Persisting();
  42
  43     @SuppressWarnings({"checkstyle:MemberName", "checkstyle:AbbreviationAsWordInName"})
  44     private final SnapshotState CREATING = new Creating();
  45
  46     private final Logger log;
  47     private final RaftActorContext context;
  48     private final LastAppliedTermInformationReader lastAppliedTermInformationReader =
  49             new LastAppliedTermInformationReader();
  50     private final ReplicatedToAllTermInformationReader replicatedToAllTermInformationReader =
  51             new ReplicatedToAllTermInformationReader();
  52
  53
  54     private SnapshotState currentState = IDLE;
  55     private CaptureSnapshot captureSnapshot;
  56     private long lastSequenceNumber = -1;
  57
  58     private Consumer<Optional<OutputStream>> createSnapshotProcedure = null;
  59
  60     private ApplySnapshot applySnapshot;
  61     private RaftActorSnapshotCohort snapshotCohort = NoopRaftActorSnapshotCohort.INSTANCE;
  62
  63     /**
  64      * Constructs an instance.
  65      *
  66      * @param context the RaftActorContext
  67      * @param logger the Logger
  68      */
  69     public SnapshotManager(final RaftActorContext context, final Logger logger) {
  70         this.context = context;
  71         this.log = logger;
  72     }
  73
  74     public boolean isApplying() {
  75         return applySnapshot != null;
  76     }
  77
  78     @Override
  79     public boolean isCapturing() {
  80         return currentState.isCapturing();
  81     }
  82
  83     @Override
  84     public boolean captureToInstall(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex,
  85             final String targetFollower) {
  86         return currentState.captureToInstall(lastLogEntry, replicatedToAllIndex, targetFollower);
  87     }
  88
  89     @Override
  90     public boolean capture(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex) {
  91         return currentState.capture(lastLogEntry, replicatedToAllIndex);
  92     }
  93
  94     @Override
  95     public void apply(final ApplySnapshot snapshot) {
  96         currentState.apply(snapshot);
  97     }
  98
  99     @Override
 100     public void persist(final Snapshot.State state, final Optional<OutputStream> installSnapshotStream,
 101             final long totalMemory) {
 102         currentState.persist(state, installSnapshotStream, totalMemory);
 103     }
 104
 105     @Override
 106     public void commit(final long sequenceNumber, final long timeStamp) {
 107         currentState.commit(sequenceNumber, timeStamp);
 108     }
 109
 110     @Override
 111     public void rollback() {
 112         currentState.rollback();
 113     }
 114
 115     @Override
 116     public long trimLog(final long desiredTrimIndex) {
 117         return currentState.trimLog(desiredTrimIndex);
 118     }
 119
 120     @SuppressWarnings("checkstyle:hiddenField")
 121     void setCreateSnapshotConsumer(final Consumer<Optional<OutputStream>> createSnapshotProcedure) {
 122         this.createSnapshotProcedure = createSnapshotProcedure;
 123     }
 124
 125     void setSnapshotCohort(final RaftActorSnapshotCohort snapshotCohort) {
 126         this.snapshotCohort = snapshotCohort;
 127     }
 128
 129     public Snapshot.@NonNull State convertSnapshot(final ByteSource snapshotBytes) throws IOException {
 130         return snapshotCohort.deserializeSnapshot(snapshotBytes);
 131     }
 132
 133     public long getLastSequenceNumber() {
 134         return lastSequenceNumber;
 135     }
 136
 137     @VisibleForTesting
 138     public CaptureSnapshot getCaptureSnapshot() {
 139         return captureSnapshot;
 140     }
 141
 142     private boolean hasFollowers() {
 143         return context.hasFollowers();
 144     }
 145
 146     private String persistenceId() {
 147         return context.getId();
 148     }
 149
 150     /**
 151      * Constructs a CaptureSnapshot instance.
 152      *
 153      * @param lastLogEntry the last log entry for the snapshot.
 154      * @param replicatedToAllIndex the index of the last entry replicated to all followers.
 155      * @return a new CaptureSnapshot instance.
 156      */
 157     public CaptureSnapshot newCaptureSnapshot(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex) {
 158         TermInformationReader lastAppliedTermInfoReader =
 159                 lastAppliedTermInformationReader.init(context.getReplicatedLog(), context.getLastApplied(),
 160                         lastLogEntry, hasFollowers());
 161
 162         long lastAppliedIndex = lastAppliedTermInfoReader.getIndex();
 163         long lastAppliedTerm = lastAppliedTermInfoReader.getTerm();
 164
 165         TermInformationReader replicatedToAllTermInfoReader =
 166                 replicatedToAllTermInformationReader.init(context.getReplicatedLog(), replicatedToAllIndex);
 167
 168         long newReplicatedToAllIndex = replicatedToAllTermInfoReader.getIndex();
 169         long newReplicatedToAllTerm = replicatedToAllTermInfoReader.getTerm();
 170
 171         List<ReplicatedLogEntry> unAppliedEntries = context.getReplicatedLog().getFrom(lastAppliedIndex + 1);
 172
 173         final long lastLogEntryIndex;
 174         final long lastLogEntryTerm;
 175         if (lastLogEntry == null) {
 176             // When we don't have journal present, for example two captureSnapshots executed right after another with no
 177             // new journal we still want to preserve the index and term in the snapshot.
 178             lastAppliedIndex = lastLogEntryIndex = context.getReplicatedLog().getSnapshotIndex();
 179             lastAppliedTerm = lastLogEntryTerm = context.getReplicatedLog().getSnapshotTerm();
 180
 181             log.debug("{}: Capturing Snapshot : lastLogEntry is null. Using snapshot values lastAppliedIndex {} and "
 182                     + "lastAppliedTerm {} instead.", persistenceId(), lastAppliedIndex, lastAppliedTerm);
 183         } else {
 184             lastLogEntryIndex = lastLogEntry.getIndex();
 185             lastLogEntryTerm = lastLogEntry.getTerm();
 186         }
 187
 188         return new CaptureSnapshot(lastLogEntryIndex, lastLogEntryTerm, lastAppliedIndex, lastAppliedTerm,
 189                 newReplicatedToAllIndex, newReplicatedToAllTerm, unAppliedEntries);
 190     }
 191
 192     private class AbstractSnapshotState implements SnapshotState {
 193
 194         @Override
 195         public boolean isCapturing() {
 196             return true;
 197         }
 198
 199         @Override
 200         public boolean capture(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex) {
 201             log.debug("capture should not be called in state {}", this);
 202             return false;
 203         }
 204
 205         @Override
 206         public boolean captureToInstall(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex,
 207                 final String targetFollower) {
 208             log.debug("captureToInstall should not be called in state {}", this);
 209             return false;
 210         }
 211
 212         @Override
 213         public void apply(final ApplySnapshot snapshot) {
 214             log.debug("apply should not be called in state {}", this);
 215         }
 216
 217         @Override
 218         public void persist(final Snapshot.State state, final Optional<OutputStream> installSnapshotStream,
 219                 final long totalMemory) {
 220             log.debug("persist should not be called in state {}", this);
 221         }
 222
 223         @Override
 224         public void commit(final long sequenceNumber, final long timeStamp) {
 225             log.debug("commit should not be called in state {}", this);
 226         }
 227
 228         @Override
 229         public void rollback() {
 230             log.debug("rollback should not be called in state {}", this);
 231         }
 232
 233         @Override
 234         public long trimLog(final long desiredTrimIndex) {
 235             log.debug("trimLog should not be called in state {}", this);
 236             return -1;
 237         }
 238
 239         protected long doTrimLog(final long desiredTrimIndex) {
 240             //  we would want to keep the lastApplied as its used while capturing snapshots
 241             long lastApplied = context.getLastApplied();
 242             long tempMin = Math.min(desiredTrimIndex, lastApplied > -1 ? lastApplied - 1 : -1);
 243
 244             if (log.isTraceEnabled()) {
 245                 log.trace("{}: performSnapshotWithoutCapture: desiredTrimIndex: {}, lastApplied: {}, tempMin: {}",
 246                         persistenceId(), desiredTrimIndex, lastApplied, tempMin);
 247             }
 248
 249             if (tempMin > -1 && context.getReplicatedLog().isPresent(tempMin)) {
 250                 log.debug("{}: fakeSnapshot purging log to {} for term {}", persistenceId(), tempMin,
 251                         context.getTermInformation().getCurrentTerm());
 252
 253                 //use the term of the temp-min, since we check for isPresent, entry will not be null
 254                 ReplicatedLogEntry entry = context.getReplicatedLog().get(tempMin);
 255                 context.getReplicatedLog().snapshotPreCommit(tempMin, entry.getTerm());
 256                 context.getReplicatedLog().snapshotCommit();
 257                 return tempMin;
 258             }
 259
 260             final RaftActorBehavior currentBehavior = context.getCurrentBehavior();
 261             if (tempMin > currentBehavior.getReplicatedToAllIndex()) {
 262                 // It's possible a follower was lagging and an install snapshot advanced its match index past
 263                 // the current replicatedToAllIndex. Since the follower is now caught up we should advance the
 264                 // replicatedToAllIndex (to tempMin). The fact that tempMin wasn't found in the log is likely
 265                 // due to a previous snapshot triggered by the memory threshold exceeded, in that case we
 266                 // trim the log to the last applied index even if previous entries weren't replicated to all followers.
 267                 currentBehavior.setReplicatedToAllIndex(tempMin);
 268             }
 269             return -1;
 270         }
 271     }
 272
 273     private class Idle extends AbstractSnapshotState {
 274
 275         @Override
 276         public boolean isCapturing() {
 277             return false;
 278         }
 279
 280         @SuppressWarnings("checkstyle:IllegalCatch")
 281         private boolean capture(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex,
 282                 final String targetFollower) {
 283             captureSnapshot = newCaptureSnapshot(lastLogEntry, replicatedToAllIndex);
 284
 285             OutputStream installSnapshotStream = null;
 286             if (targetFollower != null) {
 287                 installSnapshotStream = context.getFileBackedOutputStreamFactory().newInstance();
 288                 log.info("{}: Initiating snapshot capture {} to install on {}",
 289                         persistenceId(), captureSnapshot, targetFollower);
 290             } else {
 291                 log.info("{}: Initiating snapshot capture {}", persistenceId(), captureSnapshot);
 292             }
 293
 294             lastSequenceNumber = context.getPersistenceProvider().getLastSequenceNumber();
 295
 296             log.debug("{}: lastSequenceNumber prior to capture: {}", persistenceId(), lastSequenceNumber);
 297
 298             SnapshotManager.this.currentState = CREATING;
 299
 300             try {
 301                 createSnapshotProcedure.accept(Optional.ofNullable(installSnapshotStream));
 302             } catch (Exception e) {
 303                 SnapshotManager.this.currentState = IDLE;
 304                 log.error("Error creating snapshot", e);
 305                 return false;
 306             }
 307
 308             return true;
 309         }
 310
 311         @Override
 312         public boolean capture(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex) {
 313             return capture(lastLogEntry, replicatedToAllIndex, null);
 314         }
 315
 316         @Override
 317         public boolean captureToInstall(final ReplicatedLogEntry lastLogEntry, final long replicatedToAllIndex,
 318                 final String targetFollower) {
 319             return capture(lastLogEntry, replicatedToAllIndex, targetFollower);
 320         }
 321
 322         @Override
 323         public void apply(final ApplySnapshot toApply) {
 324             SnapshotManager.this.applySnapshot = toApply;
 325
 326             lastSequenceNumber = context.getPersistenceProvider().getLastSequenceNumber();
 327
 328             log.debug("lastSequenceNumber prior to persisting applied snapshot: {}", lastSequenceNumber);
 329
 330             context.getPersistenceProvider().saveSnapshot(toApply.getSnapshot());
 331
 332             SnapshotManager.this.currentState = PERSISTING;
 333         }
 334
 335         @Override
 336         public String toString() {
 337             return "Idle";
 338         }
 339
 340         @Override
 341         public long trimLog(final long desiredTrimIndex) {
 342             return doTrimLog(desiredTrimIndex);
 343         }
 344     }
 345
 346     private class Creating extends AbstractSnapshotState {
 347
 348         @Override
 349         public void persist(final Snapshot.State snapshotState, final Optional<OutputStream> installSnapshotStream,
 350                 final long totalMemory) {
 351             // create a snapshot object from the state provided and save it
 352             // when snapshot is saved async, SaveSnapshotSuccess is raised.
 353
 354             Snapshot snapshot = Snapshot.create(snapshotState,
 355                     captureSnapshot.getUnAppliedEntries(),
 356                     captureSnapshot.getLastIndex(), captureSnapshot.getLastTerm(),
 357                     captureSnapshot.getLastAppliedIndex(), captureSnapshot.getLastAppliedTerm(),
 358                     context.getTermInformation().getCurrentTerm(),
 359                     context.getTermInformation().getVotedFor(), context.getPeerServerInfo(true));
 360
 361             context.getPersistenceProvider().saveSnapshot(snapshot);
 362
 363             log.info("{}: Persisting of snapshot done: {}", persistenceId(), snapshot);
 364
 365             long dataThreshold = totalMemory * context.getConfigParams().getSnapshotDataThresholdPercentage() / 100;
 366             boolean dataSizeThresholdExceeded = context.getReplicatedLog().dataSize() > dataThreshold;
 367
 368             boolean logSizeExceededSnapshotBatchCount =
 369                     context.getReplicatedLog().size() >= context.getConfigParams().getSnapshotBatchCount();
 370
 371             final RaftActorBehavior currentBehavior = context.getCurrentBehavior();
 372             if (dataSizeThresholdExceeded || logSizeExceededSnapshotBatchCount) {
 373                 if (log.isDebugEnabled()) {
 374                     if (dataSizeThresholdExceeded) {
 375                         log.debug("{}: log data size {} exceeds the memory threshold {} - doing snapshotPreCommit "
 376                                 + "with index {}", context.getId(), context.getReplicatedLog().dataSize(),
 377                                 dataThreshold, captureSnapshot.getLastAppliedIndex());
 378                     } else {
 379                         log.debug("{}: log size {} exceeds the snapshot batch count {} - doing snapshotPreCommit with "
 380                                 + "index {}", context.getId(), context.getReplicatedLog().size(),
 381                                 context.getConfigParams().getSnapshotBatchCount(),
 382                                 captureSnapshot.getLastAppliedIndex());
 383                     }
 384                 }
 385
 386                 // We either exceeded the memory threshold or the log size exceeded the snapshot batch
 387                 // count so, to keep the log memory footprint in check, clear the log based on lastApplied.
 388                 // This could/should only happen if one of the followers is down as normally we keep
 389                 // removing from the log as entries are replicated to all.
 390                 context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getLastAppliedIndex(),
 391                         captureSnapshot.getLastAppliedTerm());
 392
 393                 // Don't reset replicatedToAllIndex to -1 as this may prevent us from trimming the log after an
 394                 // install snapshot to a follower.
 395                 if (captureSnapshot.getReplicatedToAllIndex() >= 0) {
 396                     currentBehavior.setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
 397                 }
 398
 399             } else if (captureSnapshot.getReplicatedToAllIndex() != -1) {
 400                 // clear the log based on replicatedToAllIndex
 401                 context.getReplicatedLog().snapshotPreCommit(captureSnapshot.getReplicatedToAllIndex(),
 402                         captureSnapshot.getReplicatedToAllTerm());
 403
 404                 currentBehavior.setReplicatedToAllIndex(captureSnapshot.getReplicatedToAllIndex());
 405             } else {
 406                 // The replicatedToAllIndex was not found in the log
 407                 // This means that replicatedToAllIndex never moved beyond -1 or that it is already in the snapshot.
 408                 // In this scenario we may need to save the snapshot to the akka persistence
 409                 // snapshot for recovery but we do not need to do the replicated log trimming.
 410                 context.getReplicatedLog().snapshotPreCommit(context.getReplicatedLog().getSnapshotIndex(),
 411                         context.getReplicatedLog().getSnapshotTerm());
 412             }
 413
 414             log.info("{}: Removed in-memory snapshotted entries, adjusted snaphsotIndex: {} and term: {}",
 415                     context.getId(), context.getReplicatedLog().getSnapshotIndex(),
 416                     context.getReplicatedLog().getSnapshotTerm());
 417
 418             if (installSnapshotStream.isPresent()) {
 419                 if (context.getId().equals(currentBehavior.getLeaderId())) {
 420                     try {
 421                         ByteSource snapshotBytes = ((FileBackedOutputStream)installSnapshotStream.get()).asByteSource();
 422                         currentBehavior.handleMessage(context.getActor(),
 423                                 new SendInstallSnapshot(snapshot, snapshotBytes));
 424                     } catch (IOException e) {
 425                         log.error("{}: Snapshot install failed due to an unrecoverable streaming error",
 426                                 context.getId(), e);
 427                     }
 428                 } else {
 429                     ((FileBackedOutputStream)installSnapshotStream.get()).cleanup();
 430                 }
 431             }
 432
 433             captureSnapshot = null;
 434             SnapshotManager.this.currentState = PERSISTING;
 435         }
 436
 437         @Override
 438         public String toString() {
 439             return "Creating";
 440         }
 441
 442     }
 443
 444     private class Persisting extends AbstractSnapshotState {
 445
 446         @Override
 447         @SuppressWarnings("checkstyle:IllegalCatch")
 448         public void commit(final long sequenceNumber, final long timeStamp) {
 449             log.debug("{}: Snapshot success -  sequence number: {}", persistenceId(), sequenceNumber);
 450
 451             if (applySnapshot != null) {
 452                 try {
 453                     Snapshot snapshot = applySnapshot.getSnapshot();
 454
 455                     //clears the followers log, sets the snapshot index to ensure adjusted-index works
 456                     context.setReplicatedLog(ReplicatedLogImpl.newInstance(snapshot, context));
 457                     context.setLastApplied(snapshot.getLastAppliedIndex());
 458                     context.setCommitIndex(snapshot.getLastAppliedIndex());
 459                     context.getTermInformation().update(snapshot.getElectionTerm(), snapshot.getElectionVotedFor());
 460
 461                     if (snapshot.getServerConfiguration() != null) {
 462                         context.updatePeerIds(snapshot.getServerConfiguration());
 463                     }
 464
 465                     if (!(snapshot.getState() instanceof EmptyState)) {
 466                         snapshotCohort.applySnapshot(snapshot.getState());
 467                     }
 468
 469                     applySnapshot.getCallback().onSuccess();
 470                 } catch (Exception e) {
 471                     log.error("{}: Error applying snapshot", context.getId(), e);
 472                 }
 473             } else {
 474                 context.getReplicatedLog().snapshotCommit();
 475             }
 476
 477             context.getPersistenceProvider().deleteSnapshots(new SnapshotSelectionCriteria(scala.Long.MaxValue(),
 478                     timeStamp - 1, 0L, 0L));
 479
 480             context.getPersistenceProvider().deleteMessages(lastSequenceNumber);
 481
 482             snapshotComplete();
 483         }
 484
 485         @Override
 486         public void rollback() {
 487             // Nothing to rollback if we're applying a snapshot from the leader.
 488             if (applySnapshot == null) {
 489                 context.getReplicatedLog().snapshotRollback();
 490
 491                 log.info("{}: Replicated Log rolled back. Snapshot will be attempted in the next cycle."
 492                         + "snapshotIndex:{}, snapshotTerm:{}, log-size:{}", persistenceId(),
 493                         context.getReplicatedLog().getSnapshotIndex(),
 494                         context.getReplicatedLog().getSnapshotTerm(),
 495                         context.getReplicatedLog().size());
 496             } else {
 497                 applySnapshot.getCallback().onFailure();
 498             }
 499
 500             snapshotComplete();
 501         }
 502
 503         private void snapshotComplete() {
 504             lastSequenceNumber = -1;
 505             applySnapshot = null;
 506             SnapshotManager.this.currentState = IDLE;
 507
 508             context.getActor().tell(SnapshotComplete.INSTANCE, context.getActor());
 509         }
 510
 511         @Override
 512         public String toString() {
 513             return "Persisting";
 514         }
 515
 516     }
 517
 518     private interface TermInformationReader {
 519         long getIndex();
 520
 521         long getTerm();
 522     }
 523
 524     static class LastAppliedTermInformationReader implements TermInformationReader {
 525         private long index;
 526         private long term;
 527
 528         LastAppliedTermInformationReader init(final ReplicatedLog log, final long originalIndex,
 529                 final ReplicatedLogEntry lastLogEntry, final boolean hasFollowers) {
 530             ReplicatedLogEntry entry = log.get(originalIndex);
 531             this.index = -1L;
 532             this.term = -1L;
 533             if (!hasFollowers) {
 534                 if (lastLogEntry != null) {
 535                     // since we have persisted the last-log-entry to persistent journal before the capture,
 536                     // we would want to snapshot from this entry.
 537                     index = lastLogEntry.getIndex();
 538                     term = lastLogEntry.getTerm();
 539                 }
 540             } else if (entry != null) {
 541                 index = entry.getIndex();
 542                 term = entry.getTerm();
 543             } else if (log.getSnapshotIndex() > -1) {
 544                 index = log.getSnapshotIndex();
 545                 term = log.getSnapshotTerm();
 546             }
 547             return this;
 548         }
 549
 550         @Override
 551         public long getIndex() {
 552             return this.index;
 553         }
 554
 555         @Override
 556         public long getTerm() {
 557             return this.term;
 558         }
 559     }
 560
 561     private static class ReplicatedToAllTermInformationReader implements TermInformationReader {
 562         private long index;
 563         private long term;
 564
 565         ReplicatedToAllTermInformationReader init(final ReplicatedLog log, final long originalIndex) {
 566             ReplicatedLogEntry entry = log.get(originalIndex);
 567             this.index = -1L;
 568             this.term = -1L;
 569
 570             if (entry != null) {
 571                 index = entry.getIndex();
 572                 term = entry.getTerm();
 573             }
 574
 575             return this;
 576         }
 577
 578         @Override
 579         public long getIndex() {
 580             return this.index;
 581         }
 582
 583         @Override
 584         public long getTerm() {
 585             return this.term;
 586         }
 587     }
 588 }