Replicate max seq_no of updates to replicas

server/src/main/java/org/elasticsearch/action/support/replication/ReplicationOperation.java

@@ -31,6 +31,7 @@
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.index.seqno.SequenceNumbers;
 import org.elasticsearch.index.shard.ReplicationGroup;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.rest.RestStatus;
@@ -114,9 +115,13 @@ public void execute() throws Exception {
             // of the sampled replication group, and advanced further than what the given replication group would allow it to.
             // This would entail that some shards could learn about a global checkpoint that would be higher than its local checkpoint.
             final long globalCheckpoint = primary.globalCheckpoint();
+            // we have to capture the max_seq_no_of_updates after this request was completed on the primary to make sure the value of
+            // max_seq_no_of_updates on replica when this request is executed is at least the value on the primary when it was executed on.
+            final long maxSeqNoOfUpdatesOrDeletes = primary.maxSeqNoOfUpdatesOrDeletes();
+            assert maxSeqNoOfUpdatesOrDeletes != SequenceNumbers.UNASSIGNED_SEQ_NO : "seqno_of_updates still uninitialized";
             final ReplicationGroup replicationGroup = primary.getReplicationGroup();
             markUnavailableShardsAsStale(replicaRequest, replicationGroup);
-            performOnReplicas(replicaRequest, globalCheckpoint, replicationGroup);
+            performOnReplicas(replicaRequest, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, replicationGroup);
         }
 
         successfulShards.incrementAndGet();  // mark primary as successful
@@ -136,7 +141,7 @@ private void markUnavailableShardsAsStale(ReplicaRequest replicaRequest, Replica
     }
 
     private void performOnReplicas(final ReplicaRequest replicaRequest, final long globalCheckpoint,
-                                   final ReplicationGroup replicationGroup) {
+                                   final long maxSeqNoOfUpdatesOrDeletes, final ReplicationGroup replicationGroup) {
         // for total stats, add number of unassigned shards and
         // number of initializing shards that are not ready yet to receive operations (recovery has not opened engine yet on the target)
         totalShards.addAndGet(replicationGroup.getSkippedShards().size());
@@ -145,19 +150,20 @@ private void performOnReplicas(final ReplicaRequest replicaRequest, final long g
 
         for (final ShardRouting shard : replicationGroup.getReplicationTargets()) {
             if (shard.isSameAllocation(primaryRouting) == false) {
-                performOnReplica(shard, replicaRequest, globalCheckpoint);
+                performOnReplica(shard, replicaRequest, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes);
             }
         }
     }
 
-    private void performOnReplica(final ShardRouting shard, final ReplicaRequest replicaRequest, final long globalCheckpoint) {
+    private void performOnReplica(final ShardRouting shard, final ReplicaRequest replicaRequest,
+                                  final long globalCheckpoint, final long maxSeqNoOfUpdatesOrDeletes) {
         if (logger.isTraceEnabled()) {
             logger.trace("[{}] sending op [{}] to replica {} for request [{}]", shard.shardId(), opType, shard, replicaRequest);
         }
 
         totalShards.incrementAndGet();
         pendingActions.incrementAndGet();
-        replicasProxy.performOn(shard, replicaRequest, globalCheckpoint, new ActionListener<ReplicaResponse>() {
+        replicasProxy.performOn(shard, replicaRequest, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, new ActionListener<ReplicaResponse>() {
             @Override
             public void onResponse(ReplicaResponse response) {
                 successfulShards.incrementAndGet();
@@ -322,6 +328,12 @@ public interface Primary<
          */
         long globalCheckpoint();
 
+        /**
+         * Returns the maximum seq_no of updates (index operations overwrite Lucene) or deletes on the primary.
+         * This value must be captured after the execution of a replication request on the primary is completed.
+         */
+        long maxSeqNoOfUpdatesOrDeletes();
+
         /**
          * Returns the current replication group on the primary shard
          *
@@ -338,12 +350,15 @@ public interface Replicas<RequestT extends ReplicationRequest<RequestT>> {
         /**
          * Performs the specified request on the specified replica.
          *
-         * @param replica          the shard this request should be executed on
-         * @param replicaRequest   the operation to perform
-         * @param globalCheckpoint the global checkpoint on the primary
-         * @param listener         callback for handling the response or failure
+         * @param replica                    the shard this request should be executed on
+         * @param replicaRequest             the operation to perform
+         * @param globalCheckpoint           the global checkpoint on the primary
+         * @param maxSeqNoOfUpdatesOrDeletes the max seq_no of updates (index operations overwriting Lucene) or deletes on primary
+         *                                   after this replication was executed on it.
+         * @param listener                   callback for handling the response or failure
          */
-        void performOn(ShardRouting replica, RequestT replicaRequest, long globalCheckpoint, ActionListener<ReplicaResponse> listener);
+        void performOn(ShardRouting replica, RequestT replicaRequest, long globalCheckpoint,
+                       long maxSeqNoOfUpdatesOrDeletes, ActionListener<ReplicaResponse> listener);
 
         /**
          * Fail the specified shard if needed, removing it from the current set

server/src/main/java/org/elasticsearch/action/support/replication/TransportReplicationAction.java

@@ -200,7 +200,7 @@ protected abstract PrimaryResult<ReplicaRequest, Response> shardOperationOnPrima
 
     /**
      * Synchronously execute the specified replica operation. This is done under a permit from
-     * {@link IndexShard#acquireReplicaOperationPermit(long, long, ActionListener, String, Object)}.
+     * {@link IndexShard#acquireReplicaOperationPermit(long, long, long, ActionListener, String, Object)}.
      *
      * @param shardRequest the request to the replica shard
      * @param replica      the replica shard to perform the operation on
@@ -489,6 +489,7 @@ public void messageReceived(
                     replicaRequest.getTargetAllocationID(),
                     replicaRequest.getPrimaryTerm(),
                     replicaRequest.getGlobalCheckpoint(),
+                    replicaRequest.getMaxSeqNoOfUpdatesOrDeletes(),
                     channel,
                     (ReplicationTask) task).run();
         }
@@ -513,6 +514,7 @@ private final class AsyncReplicaAction extends AbstractRunnable implements Actio
         private final String targetAllocationID;
         private final long primaryTerm;
         private final long globalCheckpoint;
+        private final long maxSeqNoOfUpdatesOrDeletes;
         private final TransportChannel channel;
         private final IndexShard replica;
         /**
@@ -528,6 +530,7 @@ private final class AsyncReplicaAction extends AbstractRunnable implements Actio
                 String targetAllocationID,
                 long primaryTerm,
                 long globalCheckpoint,
+                long maxSeqNoOfUpdatesOrDeletes,
                 TransportChannel channel,
                 ReplicationTask task) {
             this.request = request;
@@ -536,6 +539,7 @@ private final class AsyncReplicaAction extends AbstractRunnable implements Actio
             this.targetAllocationID = targetAllocationID;
             this.primaryTerm = primaryTerm;
             this.globalCheckpoint = globalCheckpoint;
+            this.maxSeqNoOfUpdatesOrDeletes = maxSeqNoOfUpdatesOrDeletes;
             final ShardId shardId = request.shardId();
             assert shardId != null : "request shardId must be set";
             this.replica = getIndexShard(shardId);
@@ -575,7 +579,8 @@ public void onNewClusterState(ClusterState state) {
                             new TransportChannelResponseHandler<>(logger, channel, extraMessage,
                                 () -> TransportResponse.Empty.INSTANCE);
                         transportService.sendRequest(clusterService.localNode(), transportReplicaAction,
-                            new ConcreteReplicaRequest<>(request, targetAllocationID, primaryTerm, globalCheckpoint),
+                            new ConcreteReplicaRequest<>(request, targetAllocationID, primaryTerm,
+                                globalCheckpoint, maxSeqNoOfUpdatesOrDeletes),
                             handler);
                     }
 
@@ -613,7 +618,7 @@ protected void doRun() throws Exception {
                 throw new ShardNotFoundException(this.replica.shardId(), "expected aID [{}] but found [{}]", targetAllocationID,
                     actualAllocationId);
             }
-            replica.acquireReplicaOperationPermit(primaryTerm, globalCheckpoint, this, executor, request);
+            replica.acquireReplicaOperationPermit(primaryTerm, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes, this, executor, request);
         }
 
         /**
@@ -1023,6 +1028,11 @@ public long globalCheckpoint() {
             return indexShard.getGlobalCheckpoint();
         }
 
+        @Override
+        public long maxSeqNoOfUpdatesOrDeletes() {
+            return indexShard.getMaxSeqNoOfUpdatesOrDeletes();
+        }
+
         @Override
         public ReplicationGroup getReplicationGroup() {
             return indexShard.getReplicationGroup();
@@ -1107,15 +1117,16 @@ public void performOn(
                 final ShardRouting replica,
                 final ReplicaRequest request,
                 final long globalCheckpoint,
+                final long maxSeqNoOfUpdatesOrDeletes,
                 final ActionListener<ReplicationOperation.ReplicaResponse> listener) {
             String nodeId = replica.currentNodeId();
             final DiscoveryNode node = clusterService.state().nodes().get(nodeId);
             if (node == null) {
                 listener.onFailure(new NoNodeAvailableException("unknown node [" + nodeId + "]"));
                 return;
             }
-            final ConcreteReplicaRequest<ReplicaRequest> replicaRequest =
-                    new ConcreteReplicaRequest<>(request, replica.allocationId().getId(), primaryTerm, globalCheckpoint);
+            final ConcreteReplicaRequest<ReplicaRequest> replicaRequest = new ConcreteReplicaRequest<>(
+                request, replica.allocationId().getId(), primaryTerm, globalCheckpoint, maxSeqNoOfUpdatesOrDeletes);
             sendReplicaRequest(replicaRequest, node, listener);
         }
 
@@ -1263,15 +1274,17 @@ public String toString() {
     protected static final class ConcreteReplicaRequest<R extends TransportRequest> extends ConcreteShardRequest<R> {
 
         private long globalCheckpoint;
+        private long maxSeqNoOfUpdatesOrDeletes;
 
         public ConcreteReplicaRequest(final Supplier<R> requestSupplier) {
             super(requestSupplier);
         }
 
         public ConcreteReplicaRequest(final R request, final String targetAllocationID, final long primaryTerm,
-                                      final long globalCheckpoint) {
+                                      final long globalCheckpoint, final long maxSeqNoOfUpdatesOrDeletes) {
             super(request, targetAllocationID, primaryTerm);
             this.globalCheckpoint = globalCheckpoint;
+            this.maxSeqNoOfUpdatesOrDeletes = maxSeqNoOfUpdatesOrDeletes;
         }
 
         @Override
@@ -1282,6 +1295,13 @@ public void readFrom(StreamInput in) throws IOException {
             } else {
                 globalCheckpoint = SequenceNumbers.UNASSIGNED_SEQ_NO;
             }
+            if (in.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+                maxSeqNoOfUpdatesOrDeletes = in.readZLong();
+            } else {
+                // UNASSIGNED_SEQ_NO (-2) means uninitialized, and replicas will disable
+                // optimization using seq_no if its max_seq_no_of_updates is still uninitialized
+                maxSeqNoOfUpdatesOrDeletes = SequenceNumbers.UNASSIGNED_SEQ_NO;
+            }
         }
 
         @Override
@@ -1290,19 +1310,27 @@ public void writeTo(StreamOutput out) throws IOException {
             if (out.getVersion().onOrAfter(Version.V_6_0_0_alpha1)) {
                 out.writeZLong(globalCheckpoint);
             }
+            if (out.getVersion().onOrAfter(Version.V_7_0_0_alpha1)) {
+                out.writeZLong(maxSeqNoOfUpdatesOrDeletes);
+            }
         }
 
         public long getGlobalCheckpoint() {
             return globalCheckpoint;
         }
 
+        public long getMaxSeqNoOfUpdatesOrDeletes() {
+            return maxSeqNoOfUpdatesOrDeletes;
+        }
+
         @Override
         public String toString() {
             return "ConcreteReplicaRequest{" +
                     "targetAllocationID='" + getTargetAllocationID() + '\'' +
                     ", primaryTerm='" + getPrimaryTerm() + '\'' +
                     ", request=" + getRequest() +
                     ", globalCheckpoint=" + globalCheckpoint +
+                    ", maxSeqNoOfUpdatesOrDeletes=" + maxSeqNoOfUpdatesOrDeletes +
                     '}';
         }
     }

server/src/main/java/org/elasticsearch/index/engine/InternalEngine.java

@@ -47,6 +47,7 @@
 import org.apache.lucene.util.InfoStream;
 import org.elasticsearch.Assertions;
 import org.elasticsearch.ExceptionsHelper;
+import org.elasticsearch.Version;
 import org.elasticsearch.action.index.IndexRequest;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.SuppressForbidden;
@@ -976,6 +977,7 @@ private IndexResult indexIntoLucene(Index index, IndexingStrategy plan)
             if (plan.addStaleOpToLucene) {
                 addStaleDocs(index.docs(), indexWriter);
             } else if (plan.useLuceneUpdateDocument) {
+                assert assertMaxSeqNoOfUpdatesIsAdvanced(index.uid(), plan.seqNoForIndexing, true, true);
                 updateDocs(index.uid(), index.docs(), indexWriter);
             } else {
                 // document does not exists, we can optimize for create, but double check if assertions are running
@@ -1275,8 +1277,8 @@ protected final DeletionStrategy planDeletionAsPrimary(Delete delete) throws IOE
         return plan;
     }
 
-    private DeleteResult deleteInLucene(Delete delete, DeletionStrategy plan)
-        throws IOException {
+    private DeleteResult deleteInLucene(Delete delete, DeletionStrategy plan) throws IOException {
+        assert assertMaxSeqNoOfUpdatesIsAdvanced(delete.uid(), plan.seqNoOfDeletion, false, false);
         try {
             if (softDeleteEnabled) {
                 final ParsedDocument tombstone = engineConfig.getTombstoneDocSupplier().newDeleteTombstoneDoc(delete.type(), delete.id());
@@ -2556,6 +2558,29 @@ private void updateAutoIdTimestamp(long newTimestamp, boolean unsafe) {
         assert maxUnsafeAutoIdTimestamp.get() <= maxSeenAutoIdTimestamp.get();
     }
 
+    private boolean assertMaxSeqNoOfUpdatesIsAdvanced(Term id, long seqNo, boolean allowDeleted, boolean relaxIfGapInSeqNo) {
+        final long maxSeqNoOfUpdates = getMaxSeqNoOfUpdatesOrDeletes();
+        // If the primary is on an old version which does not replicate msu, we need to relax this assertion for that.
+        if (maxSeqNoOfUpdates == SequenceNumbers.UNASSIGNED_SEQ_NO) {
+            assert config().getIndexSettings().getIndexVersionCreated().before(Version.V_7_0_0_alpha1);
+            return true;
+        }
+        // We treat a delete on the tombstones on replicas as a regular document, then use updateDocument (not addDocument).
+        if (allowDeleted) {
+            final VersionValue versionValue = versionMap.getVersionForAssert(id.bytes());
+            if (versionValue != null && versionValue.isDelete()) {
+                return true;
+            }
+        }
+        // Operations can be processed on a replica in a different order than on the primary. If the order on the primary is index-1,
+        // delete-2, index-3, and the order on a replica is index-1, index-3, delete-2, then the msu of index-3 on the replica is 2
+        // even though it is an update (overwrites index-1). We should relax this assertion if there is a pending gap in the seq_no.
+        if (relaxIfGapInSeqNo && getLocalCheckpoint() < maxSeqNoOfUpdates) {
+            return true;
+        }
+        assert seqNo <= maxSeqNoOfUpdates : "id=" + id + " seq_no=" + seqNo + " msu=" + maxSeqNoOfUpdates;
+        return true;
+    }
 
     @Override
     public void initializeMaxSeqNoOfUpdatesOrDeletes() {