send requests only to data nodes; and fix merge conflict with name change

Author: DiannaHohensee

server/src/internalClusterTest/java/org/elasticsearch/cluster/ClusterInfoServiceIT.java

@@ -388,7 +388,7 @@ public void testClusterInfoIncludesNodeUsageStatsForThreadPools() {
 
         final Map<String, NodeUsageStatsForThreadPools> usageStatsForThreadPools = clusterInfo.getNodeUsageStatsForThreadPools();
         logger.info("---> Thread pool usage stats reported by data nodes to the master: " + usageStatsForThreadPools);
-        assertThat(usageStatsForThreadPools.size(), equalTo(2)); // master and data node
+        assertThat(usageStatsForThreadPools.size(), equalTo(1)); // only stats from data nodes should be collectedg
         var dataNodeId = getNodeId(dataNodeName);
         var nodeUsageStatsForThreadPool = usageStatsForThreadPools.get(dataNodeId);
         assertNotNull(nodeUsageStatsForThreadPool);

server/src/main/java/org/elasticsearch/action/admin/cluster/node/usage/NodeUsageStatsForThreadPoolsAction.java

@@ -33,9 +33,12 @@ public class NodeUsageStatsForThreadPoolsAction {
      * The sender request type that will be resolved to send individual {@link NodeRequest} requests to every node in the cluster.
      */
     public static class Request extends BaseNodesRequest {
-        public Request() {
-            // Send all nodes a request by specifying null.
-            super((String[]) null);
+        /**
+         * @param nodeIds The list of nodes to which to send individual requests and collect responses from. If the list is null, all nodes
+         *                in the cluster will be sent a request.
+         */
+        public Request(String[] nodeIds) {
+            super(nodeIds);
         }
     }
 

server/src/main/java/org/elasticsearch/cluster/NodeUsageStatsForThreadPoolsCollector.java

@@ -43,10 +43,11 @@ public void collectUsageStats(
         ClusterState clusterState,
         ActionListener<Map<String, NodeUsageStatsForThreadPools>> listener
     ) {
+        var dataNodeIds = clusterState.nodes().getDataNodes().values().stream().map(node -> node.getId()).toArray(String[]::new);
         if (clusterState.getMinTransportVersion().onOrAfter(TransportVersions.TRANSPORT_NODE_USAGE_STATS_FOR_THREAD_POOLS_ACTION)) {
             client.execute(
                 TransportNodeUsageStatsForThreadPoolsAction.TYPE,
-                new NodeUsageStatsForThreadPoolsAction.Request(),
+                new NodeUsageStatsForThreadPoolsAction.Request(dataNodeIds),
                 listener.map(response -> response.getAllNodeUsageStatsForThreadPools())
             );
         } else {

server/src/main/java/org/elasticsearch/cluster/routing/ShardMovementWriteLoadSimulator.java

@@ -92,7 +92,7 @@ private static NodeUsageStatsForThreadPools.ThreadPoolUsageStats replaceWritePoo
                 (writeThreadPoolStats.averageThreadPoolUtilization() + (writeLoadDelta / writeThreadPoolStats.totalThreadPoolThreads())),
                 0.0
             ),
-            writeThreadPoolStats.averageThreadPoolQueueLatencyMillis()
+            writeThreadPoolStats.maxThreadPoolQueueLatencyMillis()
         );
     }
 }