elastic · elasticsearchmachine · Jun 17, 2025 · Jun 17, 2025 · Jun 17, 2025
diff --git a/server/src/internalClusterTest/java/org/elasticsearch/index/shard/IndexShardIT.java b/server/src/internalClusterTest/java/org/elasticsearch/index/shard/IndexShardIT.java
@@ -19,9 +19,9 @@
 import org.elasticsearch.cluster.ClusterInfoService;
 import org.elasticsearch.cluster.ClusterInfoServiceUtils;
 import org.elasticsearch.cluster.ClusterState;
+import org.elasticsearch.cluster.EstimatedHeapUsage;
+import org.elasticsearch.cluster.EstimatedHeapUsageCollector;
 import org.elasticsearch.cluster.InternalClusterInfoService;
-import org.elasticsearch.cluster.ShardHeapUsage;
-import org.elasticsearch.cluster.ShardHeapUsageCollector;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodeUtils;
@@ -123,7 +123,7 @@ public class IndexShardIT extends ESSingleNodeTestCase {
 
     @Override
     protected Collection<Class<? extends Plugin>> getPlugins() {
-        return pluginList(InternalSettingsPlugin.class, BogusShardHeapUsagePlugin.class);
+        return pluginList(InternalSettingsPlugin.class, BogusEstimatedHeapUsagePlugin.class);
     }
 
     public void testLockTryingToDelete() throws Exception {
@@ -264,31 +264,31 @@ public void testExpectedShardSizeIsPresent() throws InterruptedException {
     public void testHeapUsageEstimateIsPresent() {
         InternalClusterInfoService clusterInfoService = (InternalClusterInfoService) getInstanceFromNode(ClusterInfoService.class);
         ClusterInfoServiceUtils.refresh(clusterInfoService);
-        Map<String, ShardHeapUsage> shardHeapUsages = clusterInfoService.getClusterInfo().getShardHeapUsages();
-        assertNotNull(shardHeapUsages);
+        Map<String, EstimatedHeapUsage> estimatedHeapUsages = clusterInfoService.getClusterInfo().getEstimatedHeapUsages();
+        assertNotNull(estimatedHeapUsages);
         // Not collecting yet because it is disabled
-        assertTrue(shardHeapUsages.isEmpty());
+        assertTrue(estimatedHeapUsages.isEmpty());
 
-        // Enable collection for shard heap usages
+        // Enable collection for estimated heap usages
         updateClusterSettings(
             Settings.builder()
-                .put(InternalClusterInfoService.CLUSTER_ROUTING_ALLOCATION_SHARD_HEAP_THRESHOLD_DECIDER_ENABLED.getKey(), true)
+                .put(InternalClusterInfoService.CLUSTER_ROUTING_ALLOCATION_ESTIMATED_HEAP_THRESHOLD_DECIDER_ENABLED.getKey(), true)
                 .build()
         );
         try {
             ClusterInfoServiceUtils.refresh(clusterInfoService);
             ClusterState state = getInstanceFromNode(ClusterService.class).state();
-            shardHeapUsages = clusterInfoService.getClusterInfo().getShardHeapUsages();
-            assertEquals(state.nodes().size(), shardHeapUsages.size());
+            estimatedHeapUsages = clusterInfoService.getClusterInfo().getEstimatedHeapUsages();
+            assertEquals(state.nodes().size(), estimatedHeapUsages.size());
             for (DiscoveryNode node : state.nodes()) {
-                assertTrue(shardHeapUsages.containsKey(node.getId()));
-                ShardHeapUsage shardHeapUsage = shardHeapUsages.get(node.getId());
-                assertThat(shardHeapUsage.estimatedFreeBytes(), lessThanOrEqualTo(shardHeapUsage.totalBytes()));
+                assertTrue(estimatedHeapUsages.containsKey(node.getId()));
+                EstimatedHeapUsage estimatedHeapUsage = estimatedHeapUsages.get(node.getId());
+                assertThat(estimatedHeapUsage.estimatedFreeBytes(), lessThanOrEqualTo(estimatedHeapUsage.totalBytes()));
             }
         } finally {
             updateClusterSettings(
                 Settings.builder()
-                    .putNull(InternalClusterInfoService.CLUSTER_ROUTING_ALLOCATION_SHARD_HEAP_THRESHOLD_DECIDER_ENABLED.getKey())
+                    .putNull(InternalClusterInfoService.CLUSTER_ROUTING_ALLOCATION_ESTIMATED_HEAP_THRESHOLD_DECIDER_ENABLED.getKey())
                     .build()
             );
         }
@@ -838,11 +838,11 @@ private static void assertAllIndicesRemovedAndDeletionCompleted(Iterable<Indices
         }
     }
 
-    public static class BogusShardShardHeapUsageCollector implements ShardHeapUsageCollector {
+    public static class BogusEstimatedEstimatedHeapUsageCollector implements EstimatedHeapUsageCollector {
 
-        private final BogusShardHeapUsagePlugin plugin;
+        private final BogusEstimatedHeapUsagePlugin plugin;
 
-        public BogusShardShardHeapUsageCollector(BogusShardHeapUsagePlugin plugin) {
+        public BogusEstimatedEstimatedHeapUsageCollector(BogusEstimatedHeapUsagePlugin plugin) {
             this.plugin = plugin;
         }
 
@@ -859,7 +859,7 @@ public void collectClusterHeapUsage(ActionListener<Map<String, Long>> listener)
         }
     }
 
-    public static class BogusShardHeapUsagePlugin extends Plugin implements ClusterPlugin {
+    public static class BogusEstimatedHeapUsagePlugin extends Plugin implements ClusterPlugin {
 
         private final SetOnce<ClusterService> clusterService = new SetOnce<>();
 

diff --git a/...ticsearch.cluster.ShardHeapUsageCollector → ...earch.cluster.EstimatedHeapUsageCollector b/...ticsearch.cluster.ShardHeapUsageCollector → ...earch.cluster.EstimatedHeapUsageCollector
@@ -7,4 +7,4 @@
 # License v3.0 only", or the "Server Side Public License, v 1".
 #
 
-org.elasticsearch.index.shard.IndexShardIT$BogusShardShardHeapUsageCollector
+org.elasticsearch.index.shard.IndexShardIT$BogusEstimatedEstimatedHeapUsageCollector
diff --git a/server/src/main/java/org/elasticsearch/cluster/ClusterInfo.java b/server/src/main/java/org/elasticsearch/cluster/ClusterInfo.java
@@ -57,7 +57,7 @@ public class ClusterInfo implements ChunkedToXContent, Writeable {
     final Map<ShardId, Long> shardDataSetSizes;
     final Map<NodeAndShard, String> dataPath;
     final Map<NodeAndPath, ReservedSpace> reservedSpace;
-    final Map<String, ShardHeapUsage> shardHeapUsages;
+    final Map<String, EstimatedHeapUsage> estimatedHeapUsages;
 
     protected ClusterInfo() {
         this(Map.of(), Map.of(), Map.of(), Map.of(), Map.of(), Map.of(), Map.of());
@@ -72,7 +72,7 @@ protected ClusterInfo() {
      * @param shardDataSetSizes a shard id to data set size in bytes mapping per shard
      * @param dataPath the shard routing to datapath mapping
      * @param reservedSpace reserved space per shard broken down by node and data path
-     * @param shardHeapUsages shard heap usage broken down by node
+     * @param estimatedHeapUsages estimated heap usage broken down by node
      * @see #shardIdentifierFromRouting
      */
     public ClusterInfo(
@@ -82,15 +82,15 @@ public ClusterInfo(
         Map<ShardId, Long> shardDataSetSizes,
         Map<NodeAndShard, String> dataPath,
         Map<NodeAndPath, ReservedSpace> reservedSpace,
-        Map<String, ShardHeapUsage> shardHeapUsages
+        Map<String, EstimatedHeapUsage> estimatedHeapUsages
     ) {
         this.leastAvailableSpaceUsage = Map.copyOf(leastAvailableSpaceUsage);
         this.mostAvailableSpaceUsage = Map.copyOf(mostAvailableSpaceUsage);
         this.shardSizes = Map.copyOf(shardSizes);
         this.shardDataSetSizes = Map.copyOf(shardDataSetSizes);
         this.dataPath = Map.copyOf(dataPath);
         this.reservedSpace = Map.copyOf(reservedSpace);
-        this.shardHeapUsages = Map.copyOf(shardHeapUsages);
+        this.estimatedHeapUsages = Map.copyOf(estimatedHeapUsages);
     }
 
     public ClusterInfo(StreamInput in) throws IOException {
@@ -103,9 +103,9 @@ public ClusterInfo(StreamInput in) throws IOException {
             : in.readImmutableMap(nested -> NodeAndShard.from(new ShardRouting(nested)), StreamInput::readString);
         this.reservedSpace = in.readImmutableMap(NodeAndPath::new, ReservedSpace::new);
         if (in.getTransportVersion().onOrAfter(TransportVersions.HEAP_USAGE_IN_CLUSTER_INFO)) {
-            this.shardHeapUsages = in.readImmutableMap(ShardHeapUsage::new);
+            this.estimatedHeapUsages = in.readImmutableMap(EstimatedHeapUsage::new);
         } else {
-            this.shardHeapUsages = Map.of();
+            this.estimatedHeapUsages = Map.of();
         }
     }
 
@@ -122,7 +122,7 @@ public void writeTo(StreamOutput out) throws IOException {
         }
         out.writeMap(this.reservedSpace);
         if (out.getTransportVersion().onOrAfter(TransportVersions.HEAP_USAGE_IN_CLUSTER_INFO)) {
-            out.writeMap(this.shardHeapUsages, StreamOutput::writeWriteable);
+            out.writeMap(this.estimatedHeapUsages, StreamOutput::writeWriteable);
         }
     }
 
@@ -204,7 +204,7 @@ public Iterator<? extends ToXContent> toXContentChunked(ToXContent.Params params
                 return builder.endObject(); // NodeAndPath
             }),
             endArray() // end "reserved_sizes"
-            // NOTE: We don't serialize shardHeapUsages at this stage, to avoid
+            // NOTE: We don't serialize estimatedHeapUsages at this stage, to avoid
             // committing to API payloads until the feature is settled
         );
     }
@@ -216,8 +216,8 @@ public Iterator<? extends ToXContent> toXContentChunked(ToXContent.Params params
      * Also note that the map may not be complete, it may contain none, or a subset of the nodes in
      * the cluster at any time. It may also contain entries for nodes that have since left the cluster.
      */
-    public Map<String, ShardHeapUsage> getShardHeapUsages() {
-        return shardHeapUsages;
+    public Map<String, EstimatedHeapUsage> getEstimatedHeapUsages() {
+        return estimatedHeapUsages;
     }
 
     /**

diff --git a/server/src/main/java/org/elasticsearch/cluster/ClusterInfoSimulator.java b/server/src/main/java/org/elasticsearch/cluster/ClusterInfoSimulator.java
@@ -33,7 +33,7 @@ public class ClusterInfoSimulator {
     private final CopyOnFirstWriteMap<String, Long> shardSizes;
     private final Map<ShardId, Long> shardDataSetSizes;
     private final Map<NodeAndShard, String> dataPath;
-    private final Map<String, ShardHeapUsage> shardHeapUsages;
+    private final Map<String, EstimatedHeapUsage> estimatedHeapUsages;
 
     public ClusterInfoSimulator(RoutingAllocation allocation) {
         this.allocation = allocation;
@@ -42,7 +42,7 @@ public ClusterInfoSimulator(RoutingAllocation allocation) {
         this.shardSizes = new CopyOnFirstWriteMap<>(allocation.clusterInfo().shardSizes);
         this.shardDataSetSizes = Map.copyOf(allocation.clusterInfo().shardDataSetSizes);
         this.dataPath = Map.copyOf(allocation.clusterInfo().dataPath);
-        this.shardHeapUsages = allocation.clusterInfo().getShardHeapUsages();
+        this.estimatedHeapUsages = allocation.clusterInfo().getEstimatedHeapUsages();
     }
 
     /**
@@ -156,7 +156,7 @@ public ClusterInfo getClusterInfo() {
             shardDataSetSizes,
             dataPath,
             Map.of(),
-            shardHeapUsages
+            estimatedHeapUsages
         );
     }
 }
diff --git a/...elasticsearch/cluster/ShardHeapUsage.java → ...ticsearch/cluster/EstimatedHeapUsage.java b/...elasticsearch/cluster/ShardHeapUsage.java → ...ticsearch/cluster/EstimatedHeapUsage.java
@@ -18,14 +18,14 @@
 /**
  * Record representing an estimate of the heap used by allocated shards and ongoing merges on a particular node
  */
-public record ShardHeapUsage(String nodeId, long totalBytes, long estimatedUsageBytes) implements Writeable {
+public record EstimatedHeapUsage(String nodeId, long totalBytes, long estimatedUsageBytes) implements Writeable {
 
-    public ShardHeapUsage {
+    public EstimatedHeapUsage {
         assert totalBytes >= 0;
         assert estimatedUsageBytes >= 0;
     }
 
-    public ShardHeapUsage(StreamInput in) throws IOException {
+    public EstimatedHeapUsage(StreamInput in) throws IOException {
         this(in.readString(), in.readVLong(), in.readVLong());
     }
 

diff --git a/...arch/cluster/ShardHeapUsageCollector.java → .../cluster/EstimatedHeapUsageCollector.java b/...arch/cluster/ShardHeapUsageCollector.java → .../cluster/EstimatedHeapUsageCollector.java
@@ -14,21 +14,21 @@
 import java.util.Map;
 
 /**
- * Collect the shard heap usage for each node in the cluster.
+ * Collect the estimated heap usage for each node in the cluster.
  * <p>
  * Results are returned as a map of node ID to estimated heap usage in bytes
  *
- * @see ShardHeapUsage
+ * @see EstimatedHeapUsage
  */
-public interface ShardHeapUsageCollector {
+public interface EstimatedHeapUsageCollector {
 
     /**
-     * This will be used when there is no ShardHeapUsageCollector available
+     * This will be used when there is no EstimatedHeapUsageCollector available
      */
-    ShardHeapUsageCollector EMPTY = listener -> listener.onResponse(Map.of());
+    EstimatedHeapUsageCollector EMPTY = listener -> listener.onResponse(Map.of());
 
     /**
-     * Collect the shard heap usage for every node in the cluster
+     * Collect the estimated heap usage for every node in the cluster
      *
      * @param listener The listener which will receive the results
      */

diff --git a/server/src/main/java/org/elasticsearch/cluster/InternalClusterInfoService.java b/server/src/main/java/org/elasticsearch/cluster/InternalClusterInfoService.java
@@ -83,22 +83,22 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
         Property.NodeScope
     );
 
-    public static final Setting<Boolean> CLUSTER_ROUTING_ALLOCATION_SHARD_HEAP_THRESHOLD_DECIDER_ENABLED = Setting.boolSetting(
-        "cluster.routing.allocation.shard_heap.threshold_enabled",
+    public static final Setting<Boolean> CLUSTER_ROUTING_ALLOCATION_ESTIMATED_HEAP_THRESHOLD_DECIDER_ENABLED = Setting.boolSetting(
+        "cluster.routing.allocation.estimated_heap.threshold_enabled",
         false,
         Property.Dynamic,
         Property.NodeScope
     );
 
     private volatile boolean diskThresholdEnabled;
-    private volatile boolean shardHeapThresholdEnabled;
+    private volatile boolean estimatedHeapThresholdEnabled;
     private volatile TimeValue updateFrequency;
     private volatile TimeValue fetchTimeout;
 
     private volatile Map<String, DiskUsage> leastAvailableSpaceUsages;
     private volatile Map<String, DiskUsage> mostAvailableSpaceUsages;
     private volatile Map<String, ByteSizeValue> maxHeapPerNode;
-    private volatile Map<String, Long> shardHeapUsagePerNode;
+    private volatile Map<String, Long> estimatedHeapUsagePerNode;
     private volatile IndicesStatsSummary indicesStatsSummary;
 
     private final ThreadPool threadPool;
@@ -107,7 +107,7 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
 
     private final Object mutex = new Object();
     private final List<ActionListener<ClusterInfo>> nextRefreshListeners = new ArrayList<>();
-    private final ShardHeapUsageCollector shardHeapUsageCollector;
+    private final EstimatedHeapUsageCollector estimatedHeapUsageCollector;
 
     private AsyncRefresh currentRefresh;
     private RefreshScheduler refreshScheduler;
@@ -118,16 +118,16 @@ public InternalClusterInfoService(
         ClusterService clusterService,
         ThreadPool threadPool,
         Client client,
-        ShardHeapUsageCollector shardHeapUsageCollector
+        EstimatedHeapUsageCollector estimatedHeapUsageCollector
     ) {
         this.leastAvailableSpaceUsages = Map.of();
         this.mostAvailableSpaceUsages = Map.of();
         this.maxHeapPerNode = Map.of();
-        this.shardHeapUsagePerNode = Map.of();
+        this.estimatedHeapUsagePerNode = Map.of();
         this.indicesStatsSummary = IndicesStatsSummary.EMPTY;
         this.threadPool = threadPool;
         this.client = client;
-        this.shardHeapUsageCollector = shardHeapUsageCollector;
+        this.estimatedHeapUsageCollector = estimatedHeapUsageCollector;
         this.updateFrequency = INTERNAL_CLUSTER_INFO_UPDATE_INTERVAL_SETTING.get(settings);
         this.fetchTimeout = INTERNAL_CLUSTER_INFO_TIMEOUT_SETTING.get(settings);
         this.diskThresholdEnabled = DiskThresholdSettings.CLUSTER_ROUTING_ALLOCATION_DISK_THRESHOLD_ENABLED_SETTING.get(settings);
@@ -139,17 +139,17 @@ public InternalClusterInfoService(
             this::setDiskThresholdEnabled
         );
         clusterSettings.initializeAndWatch(
-            CLUSTER_ROUTING_ALLOCATION_SHARD_HEAP_THRESHOLD_DECIDER_ENABLED,
-            this::setShardHeapThresholdEnabled
+            CLUSTER_ROUTING_ALLOCATION_ESTIMATED_HEAP_THRESHOLD_DECIDER_ENABLED,
+            this::setEstimatedHeapThresholdEnabled
         );
     }
 
     private void setDiskThresholdEnabled(boolean diskThresholdEnabled) {
         this.diskThresholdEnabled = diskThresholdEnabled;
     }
 
-    private void setShardHeapThresholdEnabled(boolean shardHeapThresholdEnabled) {
-        this.shardHeapThresholdEnabled = shardHeapThresholdEnabled;
+    private void setEstimatedHeapThresholdEnabled(boolean estimatedHeapThresholdEnabled) {
+        this.estimatedHeapThresholdEnabled = estimatedHeapThresholdEnabled;
     }
 
     private void setFetchTimeout(TimeValue fetchTimeout) {
@@ -202,8 +202,8 @@ void execute() {
 
             try (var ignoredRefs = fetchRefs) {
                 maybeFetchIndicesStats(diskThresholdEnabled);
-                maybeFetchNodeStats(diskThresholdEnabled || shardHeapThresholdEnabled);
-                maybeFetchNodesHeapUsage(shardHeapThresholdEnabled);
+                maybeFetchNodeStats(diskThresholdEnabled || estimatedHeapThresholdEnabled);
+                maybeFetchNodesEstimatedHeapUsage(estimatedHeapThresholdEnabled);
             }
         }
 
@@ -231,28 +231,28 @@ private void maybeFetchNodeStats(boolean shouldFetch) {
             }
         }
 
-        private void maybeFetchNodesHeapUsage(boolean shouldFetch) {
+        private void maybeFetchNodesEstimatedHeapUsage(boolean shouldFetch) {
             if (shouldFetch) {
                 try (var ignored = threadPool.getThreadContext().clearTraceContext()) {
-                    fetchNodesHeapUsage();
+                    fetchNodesEstimatedHeapUsage();
                 }
             } else {
-                logger.trace("skipping collecting shard heap usage from cluster, notifying listeners with empty shard heap usage");
-                shardHeapUsagePerNode = Map.of();
+                logger.trace("skipping collecting estimated heap usage from cluster, notifying listeners with empty estimated heap usage");
+                estimatedHeapUsagePerNode = Map.of();
             }
         }
 
-        private void fetchNodesHeapUsage() {
-            shardHeapUsageCollector.collectClusterHeapUsage(ActionListener.releaseAfter(new ActionListener<>() {
+        private void fetchNodesEstimatedHeapUsage() {
+            estimatedHeapUsageCollector.collectClusterHeapUsage(ActionListener.releaseAfter(new ActionListener<>() {
                 @Override
-                public void onResponse(Map<String, Long> currentShardHeapUsages) {
-                    shardHeapUsagePerNode = currentShardHeapUsages;
+                public void onResponse(Map<String, Long> currentEstimatedHeapUsages) {
+                    estimatedHeapUsagePerNode = currentEstimatedHeapUsages;
                 }
 
                 @Override
                 public void onFailure(Exception e) {
                     logger.warn("failed to fetch heap usage for nodes", e);
-                    shardHeapUsagePerNode = Map.of();
+                    estimatedHeapUsagePerNode = Map.of();
                 }
             }, fetchRefs.acquire()));
         }
@@ -479,11 +479,11 @@ private boolean shouldRefresh() {
     @Override
     public ClusterInfo getClusterInfo() {
         final IndicesStatsSummary indicesStatsSummary = this.indicesStatsSummary; // single volatile read
-        final Map<String, ShardHeapUsage> shardHeapUsages = new HashMap<>();
+        final Map<String, EstimatedHeapUsage> estimatedHeapUsages = new HashMap<>();
         maxHeapPerNode.forEach((nodeId, maxHeapSize) -> {
-            final Long estimatedHeapUsage = shardHeapUsagePerNode.get(nodeId);
+            final Long estimatedHeapUsage = estimatedHeapUsagePerNode.get(nodeId);
             if (estimatedHeapUsage != null) {
-                shardHeapUsages.put(nodeId, new ShardHeapUsage(nodeId, maxHeapSize.getBytes(), estimatedHeapUsage));
+                estimatedHeapUsages.put(nodeId, new EstimatedHeapUsage(nodeId, maxHeapSize.getBytes(), estimatedHeapUsage));
             }
         });
         return new ClusterInfo(
@@ -493,7 +493,7 @@ public ClusterInfo getClusterInfo() {
             indicesStatsSummary.shardDataSetSizes,
             indicesStatsSummary.dataPath,
             indicesStatsSummary.reservedSpace,
-            shardHeapUsages
+            estimatedHeapUsages
         );
     }