[Remote Store] Fix relocation failure due to transport receive timeout

server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreIT.java

@@ -509,4 +509,27 @@ public void testRestoreSnapshotToIndexWithSameNameDifferentUUID() throws Excepti
  assertHitCount(client(dataNodes.get(1)).prepareSearch(INDEX_NAME).setSize(0).get(), 50);
  });
  }
+
+ public void testNoSearchIdleForAnyReplicaCount() throws ExecutionException, InterruptedException {
+ internalCluster().startClusterManagerOnlyNode();
+ String primaryShardNode = internalCluster().startDataOnlyNodes(1).get(0);
+
+ createIndex(INDEX_NAME, remoteStoreIndexSettings(0));
+ ensureGreen(INDEX_NAME);
+ IndexShard indexShard = getIndexShard(primaryShardNode);
+ assertFalse(indexShard.isSearchIdleSupported());
+
+ String replicaShardNode = internalCluster().startDataOnlyNodes(1).get(0);
+ assertAcked(
+ client().admin()
+ .indices()
+ .prepareUpdateSettings(INDEX_NAME)
+ .setSettings(Settings.builder().put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1))
+ );
+ ensureGreen(INDEX_NAME);
+ assertFalse(indexShard.isSearchIdleSupported());
+
+ indexShard = getIndexShard(replicaShardNode);
+ assertFalse(indexShard.isSearchIdleSupported());
+ }
 }

server/src/main/java/org/opensearch/index/IndexSettings.java

@@ -1024,6 +1024,9 @@
  }
 
  private void setSearchIdleAfter(TimeValue searchIdleAfter) {
+ if (this.isRemoteStoreEnabled) {
+ logger.warn("Search idle is not supported for remote backed indices");
+ }
  if (this.replicationType == ReplicationType.SEGMENT && this.getNumberOfReplicas() > 0) {
  logger.warn("Search idle is not supported for indices with replicas using 'replication.type: SEGMENT'");
  }

server/src/main/java/org/opensearch/index/shard/IndexShard.java

@@ -4425,7 +4425,6 @@ public final boolean isSearchIdle() {
  }
 
  /**
- *
  * Returns true if this shard supports search idle.
  * <p>
  * Indices using Segment Replication will ignore search idle unless there are no replicas.
@@ -4434,6 +4433,11 @@ public final boolean isSearchIdle() {
  * a new set of segments.
  */
  public final boolean isSearchIdleSupported() {
+ // If the index is remote store backed, then search idle is not supported. This is to ensure that async refresh
+ // task continues to upload to remote store periodically.
+ if (isRemoteTranslogEnabled()) {
+ return false;
+ }
  return indexSettings.isSegRepEnabled() == false || indexSettings.getNumberOfReplicas() == 0;
  }
 

server/src/main/java/org/opensearch/index/translog/InternalTranslogManager.java

@@ -430,10 +430,10 @@ public String getTranslogUUID() {
  * @return if the translog should be flushed
  */
  public boolean shouldPeriodicallyFlush(long localCheckpointOfLastCommit, long flushThreshold) {
- final long translogGenerationOfLastCommit = translog.getMinGenerationForSeqNo(
-  localCheckpointOfLastCommit + 1
- ).translogFileGeneration;
- if (translog.sizeInBytesByMinGen(translogGenerationOfLastCommit) < flushThreshold) {
+ // This is the minimum seqNo that is referred in translog and considered for calculating translog size
+ long minTranslogRefSeqNo = translog.getMinUnreferencedSeqNoInSegments(localCheckpointOfLastCommit + 1);
+ final long minReferencedTranslogGeneration = translog.getMinGenerationForSeqNo(minTranslogRefSeqNo).translogFileGeneration;
+ if (translog.sizeInBytesByMinGen(minReferencedTranslogGeneration) < flushThreshold) {
  return false;
  }
  /*
@@ -454,7 +454,7 @@ public boolean shouldPeriodicallyFlush(long localCheckpointOfLastCommit, long fl
  final long translogGenerationOfNewCommit = translog.getMinGenerationForSeqNo(
  localCheckpointTrackerSupplier.get().getProcessedCheckpoint() + 1
  ).translogFileGeneration;
- return translogGenerationOfLastCommit < translogGenerationOfNewCommit
+ return minReferencedTranslogGeneration < translogGenerationOfNewCommit
  || localCheckpointTrackerSupplier.get().getProcessedCheckpoint() == localCheckpointTrackerSupplier.get().getMaxSeqNo();
  }
 

server/src/main/java/org/opensearch/index/translog/RemoteFsTranslog.java

@@ -544,4 +544,9 @@ public void onUploadFailed(TransferSnapshot transferSnapshot, Exception ex) thro
  }
  }
  }
+
+ @Override
+ public long getMinUnreferencedSeqNoInSegments(long minUnrefCheckpointInLastCommit) {
+ return minSeqNoToKeep;
+ }
 }

server/src/main/java/org/opensearch/index/translog/Translog.java

@@ -2034,4 +2034,8 @@ public static String createEmptyTranslog(
  writer.close();
  return uuid;
  }
+
+ public long getMinUnreferencedSeqNoInSegments(long minUnrefCheckpointInLastCommit) {
+ return minUnrefCheckpointInLastCommit;
+ }
 }

server/src/main/java/org/opensearch/indices/recovery/PeerRecoverySourceService.java

@@ -376,7 +376,8 @@
  transportService,
  request.targetNode(),
  recoverySettings,
- throttleTime -> shard.recoveryStats().addThrottleTime(throttleTime)
+ throttleTime -> shard.recoveryStats().addThrottleTime(throttleTime),
+ shard.isRemoteTranslogEnabled()
  );
  handler = RecoverySourceHandlerFactory.create(shard, recoveryTarget, request, recoverySettings);
  return Tuple.tuple(handler, recoveryTarget);

server/src/main/java/org/opensearch/indices/recovery/RemoteRecoveryTargetHandler.java

@@ -75,14 +75,16 @@
  private final AtomicLong requestSeqNoGenerator = new AtomicLong(0);
  private final RetryableTransportClient retryableTransportClient;
  private final RemoteSegmentFileChunkWriter fileChunkWriter;
+ private final boolean remoteStoreEnabled;
 
  public RemoteRecoveryTargetHandler(
  long recoveryId,
  ShardId shardId,
  TransportService transportService,
  DiscoveryNode targetNode,
  RecoverySettings recoverySettings,
- Consumer<Long> onSourceThrottle
+ Consumer<Long> onSourceThrottle,
+ boolean remoteStoreEnabled
  ) {
  this.transportService = transportService;
  // It is safe to pass the retry timeout value here because RemoteRecoveryTargetHandler
@@ -111,6 +113,7 @@
  requestSeqNoGenerator,
  onSourceThrottle
  );
+ this.remoteStoreEnabled = remoteStoreEnabled;
  }
 
  public DiscoveryNode targetNode() {
@@ -129,7 +132,13 @@
  );
  final Writeable.Reader<TransportResponse.Empty> reader = in -> TransportResponse.Empty.INSTANCE;
  final ActionListener<TransportResponse.Empty> responseListener = ActionListener.map(listener, r -> null);
- retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
+ if (remoteStoreEnabled) {
+ // If remote store is enabled, during the prepare_translog phase, translog is also downloaded on the
+ // target host along with incremental segments download.
+ retryableTransportClient.executeRetryableAction(action, request, translogOpsRequestOptions, responseListener, reader);
+ } else {
+ retryableTransportClient.executeRetryableAction(action, request, responseListener, reader);
+ }
  }
 
  @Override

server/src/test/java/org/opensearch/index/shard/RemoteIndexShardTests.java

@@ -471,6 +471,15 @@ public void onReplicationFailure(
  }
  }
 
+ @Override
+ protected void validateShardIdleWithNoReplicas(IndexShard primary) {
+ // ensure search idle conditions are met.
+ assertFalse(primary.isSearchIdleSupported());
+ assertTrue(primary.isSearchIdle());
+ assertTrue(primary.scheduledRefresh());
+ assertFalse(primary.hasRefreshPending());
+ }
+
  private void assertSingleSegmentFile(IndexShard shard, String fileName) throws IOException {
  final Set<String> segmentsFileNames = Arrays.stream(shard.store().directory().listAll())
  .filter(file -> file.startsWith(IndexFileNames.SEGMENTS))

server/src/test/java/org/opensearch/index/shard/SegmentReplicationIndexShardTests.java

@@ -436,13 +436,17 @@ public void testShardIdleWithNoReplicas() throws Exception {
  shards.startAll();
  final IndexShard primary = shards.getPrimary();
  shards.indexDocs(randomIntBetween(1, 10));
- // ensure search idle conditions are met.
- assertTrue(primary.isSearchIdle());
- assertFalse(primary.scheduledRefresh());
- assertTrue(primary.hasRefreshPending());
+ validateShardIdleWithNoReplicas(primary);
  }
  }
 
+ protected void validateShardIdleWithNoReplicas(IndexShard primary) {
+ // ensure search idle conditions are met.
+ assertTrue(primary.isSearchIdle());
+ assertFalse(primary.scheduledRefresh());
+ assertTrue(primary.hasRefreshPending());
+ }
+
  /**
  * here we are starting a new primary shard in PrimaryMode and testing if the shard publishes checkpoint after refresh.
  */