diff --git a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/TransportClusterStatsAction.java b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/TransportClusterStatsAction.java
index d54465ff845..3a0d22945b4 100644
--- a/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/TransportClusterStatsAction.java
+++ b/server/src/main/java/org/elasticsearch/action/admin/cluster/stats/TransportClusterStatsAction.java
@@ -45,6 +45,7 @@ import org.elasticsearch.indices.IndicesService;
 import org.elasticsearch.node.NodeService;
 import org.elasticsearch.threadpool.ThreadPool;
 import org.elasticsearch.transport.TransportService;
+import org.elasticsearch.transport.Transports;
 
 import java.io.IOException;
 import java.util.ArrayList;
@@ -64,8 +65,8 @@ public class TransportClusterStatsAction extends TransportNodesAction<ClusterSta
     @Inject
     public TransportClusterStatsAction(ThreadPool threadPool, ClusterService clusterService, TransportService transportService,
                                        NodeService nodeService, IndicesService indicesService, ActionFilters actionFilters) {
-        super(ClusterStatsAction.NAME, threadPool, clusterService, transportService, actionFilters,
-            ClusterStatsRequest::new, ClusterStatsNodeRequest::new, ThreadPool.Names.MANAGEMENT, ClusterStatsNodeResponse.class);
+        super(ClusterStatsAction.NAME, threadPool, clusterService, transportService, actionFilters, ClusterStatsRequest::new,
+                ClusterStatsNodeRequest::new, ThreadPool.Names.MANAGEMENT, ThreadPool.Names.MANAGEMENT, ClusterStatsNodeResponse.class);
         this.nodeService = nodeService;
         this.indicesService = indicesService;
     }
@@ -73,6 +74,8 @@ public class TransportClusterStatsAction extends TransportNodesAction<ClusterSta
     @Override
     protected ClusterStatsResponse newResponse(ClusterStatsRequest request,
                                                List<ClusterStatsNodeResponse> responses, List<FailedNodeException> failures) {
+        assert Transports.assertNotTransportThread("Constructor of ClusterStatsResponse runs expensive computations on mappings found in" +
+                " the cluster state that are too slow for a transport thread");
         ClusterState state = clusterService.state();
         return new ClusterStatsResponse(
             System.currentTimeMillis(),
diff --git a/server/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java b/server/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java
index af7e48b1eeb..e6da86876dd 100644
--- a/server/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java
+++ b/server/src/main/java/org/elasticsearch/action/support/nodes/TransportNodesAction.java
@@ -21,6 +21,7 @@ package org.elasticsearch.action.support.nodes;
 
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.elasticsearch.action.ActionListener;
+import org.elasticsearch.action.ActionRunnable;
 import org.elasticsearch.action.FailedNodeException;
 import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.HandledTransportAction;
@@ -60,10 +61,24 @@ public abstract class TransportNodesAction<NodesRequest extends BaseNodesRequest
     protected final Class<NodeResponse> nodeResponseClass;
     protected final String transportNodeAction;
 
+    private final String finalExecutor;
+
+    /**
+     * @param actionName        action name
+     * @param threadPool        thread-pool
+     * @param clusterService    cluster service
+     * @param transportService  transport service
+     * @param actionFilters     action filters
+     * @param request           node request writer
+     * @param nodeRequest       node request reader
+     * @param nodeExecutor      executor to execute node action on
+     * @param finalExecutor     executor to execute final collection of all responses on
+     * @param nodeResponseClass class of the node responses
+     */
     protected TransportNodesAction(String actionName, ThreadPool threadPool,
                                    ClusterService clusterService, TransportService transportService, ActionFilters actionFilters,
                                    Writeable.Reader<NodesRequest> request, Writeable.Reader<NodeRequest> nodeRequest, String nodeExecutor,
-                                   Class<NodeResponse> nodeResponseClass) {
+                                   String finalExecutor, Class<NodeResponse> nodeResponseClass) {
         super(actionName, transportService, actionFilters, request);
         this.threadPool = threadPool;
         this.clusterService = Objects.requireNonNull(clusterService);
@@ -71,9 +86,24 @@ public abstract class TransportNodesAction<NodesRequest extends BaseNodesRequest
         this.nodeResponseClass = Objects.requireNonNull(nodeResponseClass);
 
         this.transportNodeAction = actionName + "[n]";
-
+        this.finalExecutor = finalExecutor;
         transportService.registerRequestHandler(
-            transportNodeAction, nodeExecutor, nodeRequest, new NodeTransportHandler());
+                transportNodeAction, nodeExecutor, nodeRequest, new NodeTransportHandler());
+    }
+
+    /**
+     * Same as {@link #TransportNodesAction(String, ThreadPool, ClusterService, TransportService, ActionFilters, Writeable.Reader,
+     * Writeable.Reader, String, String, Class)} but executes final response collection on the transport thread except for when the final
+     * node response is received from the local node, in which case {@code nodeExecutor} is used.
+     * This constructor should only be used for actions for which the creation of the final response is fast enough to be safely executed
+     * on a transport thread.
+     */
+    protected TransportNodesAction(String actionName, ThreadPool threadPool,
+                                   ClusterService clusterService, TransportService transportService, ActionFilters actionFilters,
+                                   Writeable.Reader<NodesRequest> request, Writeable.Reader<NodeRequest> nodeRequest, String nodeExecutor,
+                                   Class<NodeResponse> nodeResponseClass) {
+        this(actionName, threadPool, clusterService, transportService, actionFilters, request, nodeRequest, nodeExecutor,
+                ThreadPool.Names.SAME, nodeResponseClass);
     }
 
     @Override
@@ -230,15 +260,7 @@ public abstract class TransportNodesAction<NodesRequest extends BaseNodesRequest
         }
 
         private void finishHim() {
-            NodesResponse finalResponse;
-            try {
-                finalResponse = newResponse(request, responses);
-            } catch (Exception e) {
-                logger.debug("failed to combine responses from nodes", e);
-                listener.onFailure(e);
-                return;
-            }
-            listener.onResponse(finalResponse);
+            threadPool.executor(finalExecutor).execute(ActionRunnable.supply(listener, () -> newResponse(request, responses)));
         }
     }