Use HashMap inside cluster info service (#87899)

The InternalClusterInfoService internally uses ImmutableOpenMap
for keeping track of available space on each node. This commit converts
those usages to use HashMap. Note that an unmodifiableMap wrapper is
used because updates to this (from each node) are likely to happen often
as disk is used.

relates #86239

Author: rjernst

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

@@ -27,7 +27,6 @@
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.allocation.DiskThresholdSettings;
 import org.elasticsearch.cluster.service.ClusterService;
-import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.settings.ClusterSettings;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
@@ -40,6 +39,7 @@
 import org.elasticsearch.threadpool.ThreadPool;
 
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -83,8 +83,8 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
     private volatile TimeValue updateFrequency;
     private volatile TimeValue fetchTimeout;
 
-    private volatile ImmutableOpenMap<String, DiskUsage> leastAvailableSpaceUsages;
-    private volatile ImmutableOpenMap<String, DiskUsage> mostAvailableSpaceUsages;
+    private volatile Map<String, DiskUsage> leastAvailableSpaceUsages;
+    private volatile Map<String, DiskUsage> mostAvailableSpaceUsages;
     private volatile IndicesStatsSummary indicesStatsSummary;
 
     private final ThreadPool threadPool;
@@ -97,8 +97,8 @@ public class InternalClusterInfoService implements ClusterInfoService, ClusterSt
     private RefreshScheduler refreshScheduler;
 
     public InternalClusterInfoService(Settings settings, ClusterService clusterService, ThreadPool threadPool, Client client) {
-        this.leastAvailableSpaceUsages = ImmutableOpenMap.of();
-        this.mostAvailableSpaceUsages = ImmutableOpenMap.of();
+        this.leastAvailableSpaceUsages = Map.of();
+        this.mostAvailableSpaceUsages = Map.of();
         this.indicesStatsSummary = IndicesStatsSummary.EMPTY;
         this.threadPool = threadPool;
         this.client = client;
@@ -181,15 +181,15 @@ public void onResponse(NodesStatsResponse nodesStatsResponse) {
                         logger.warn(() -> "failed to retrieve stats for node [" + failure.nodeId() + "]", failure.getCause());
                     }
 
-                    ImmutableOpenMap.Builder<String, DiskUsage> leastAvailableUsagesBuilder = ImmutableOpenMap.builder();
-                    ImmutableOpenMap.Builder<String, DiskUsage> mostAvailableUsagesBuilder = ImmutableOpenMap.builder();
+                    Map<String, DiskUsage> leastAvailableUsagesBuilder = new HashMap<>();
+                    Map<String, DiskUsage> mostAvailableUsagesBuilder = new HashMap<>();
                     fillDiskUsagePerNode(
                         adjustNodesStats(nodesStatsResponse.getNodes()),
                         leastAvailableUsagesBuilder,
                         mostAvailableUsagesBuilder
                     );
-                    leastAvailableSpaceUsages = leastAvailableUsagesBuilder.build();
-                    mostAvailableSpaceUsages = mostAvailableUsagesBuilder.build();
+                    leastAvailableSpaceUsages = Collections.unmodifiableMap(leastAvailableUsagesBuilder);
+                    mostAvailableSpaceUsages = Collections.unmodifiableMap(mostAvailableUsagesBuilder);
                 }
 
                 @Override
@@ -199,8 +199,8 @@ public void onFailure(Exception e) {
                     } else {
                         logger.warn("failed to retrieve node stats", e);
                     }
-                    leastAvailableSpaceUsages = ImmutableOpenMap.of();
-                    mostAvailableSpaceUsages = ImmutableOpenMap.of();
+                    leastAvailableSpaceUsages = Map.of();
+                    mostAvailableSpaceUsages = Map.of();
                 }
             }, this::onStatsProcessed));
 
@@ -246,9 +246,9 @@ public void onResponse(IndicesStatsResponse indicesStatsResponse) {
                     }
 
                     final ShardStats[] stats = indicesStatsResponse.getShards();
-                    final ImmutableOpenMap.Builder<String, Long> shardSizeByIdentifierBuilder = ImmutableOpenMap.builder();
-                    final ImmutableOpenMap.Builder<ShardId, Long> shardDataSetSizeBuilder = ImmutableOpenMap.builder();
-                    final ImmutableOpenMap.Builder<ShardRouting, String> dataPathByShardRoutingBuilder = ImmutableOpenMap.builder();
+                    final Map<String, Long> shardSizeByIdentifierBuilder = new HashMap<>();
+                    final Map<ShardId, Long> shardDataSetSizeBuilder = new HashMap<>();
+                    final Map<ShardRouting, String> dataPathByShardRoutingBuilder = new HashMap<>();
                     final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace.Builder> reservedSpaceBuilders = new HashMap<>();
                     buildShardLevelInfo(
                         stats,
@@ -258,15 +258,14 @@ public void onResponse(IndicesStatsResponse indicesStatsResponse) {
                         reservedSpaceBuilders
                     );
 
-                    final ImmutableOpenMap.Builder<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> rsrvdSpace = ImmutableOpenMap
-                        .builder();
+                    final Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> rsrvdSpace = new HashMap<>();
                     reservedSpaceBuilders.forEach((nodeAndPath, builder) -> rsrvdSpace.put(nodeAndPath, builder.build()));
 
                     indicesStatsSummary = new IndicesStatsSummary(
-                        shardSizeByIdentifierBuilder.build(),
-                        shardDataSetSizeBuilder.build(),
-                        dataPathByShardRoutingBuilder.build(),
-                        rsrvdSpace.build()
+                        Collections.unmodifiableMap(shardSizeByIdentifierBuilder),
+                        Collections.unmodifiableMap(shardDataSetSizeBuilder),
+                        Collections.unmodifiableMap(dataPathByShardRoutingBuilder),
+                        Collections.unmodifiableMap(rsrvdSpace)
                     );
                 }
 
@@ -342,8 +341,8 @@ private Runnable getNewRefresh() {
             return currentRefresh::execute;
         } else {
             return () -> {
-                leastAvailableSpaceUsages = ImmutableOpenMap.of();
-                mostAvailableSpaceUsages = ImmutableOpenMap.of();
+                leastAvailableSpaceUsages = Map.of();
+                mostAvailableSpaceUsages = Map.of();
                 indicesStatsSummary = IndicesStatsSummary.EMPTY;
                 thisRefreshListeners.forEach(l -> l.onResponse(ClusterInfo.EMPTY));
             };
@@ -413,9 +412,9 @@ public void addListener(Consumer<ClusterInfo> clusterInfoConsumer) {
 
     static void buildShardLevelInfo(
         ShardStats[] stats,
-        ImmutableOpenMap.Builder<String, Long> shardSizes,
-        ImmutableOpenMap.Builder<ShardId, Long> shardDataSetSizeBuilder,
-        ImmutableOpenMap.Builder<ShardRouting, String> newShardRoutingToDataPath,
+        Map<String, Long> shardSizes,
+        Map<ShardId, Long> shardDataSetSizeBuilder,
+        Map<ShardRouting, String> newShardRoutingToDataPath,
         Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace.Builder> reservedSpaceByShard
     ) {
         for (ShardStats s : stats) {
@@ -448,8 +447,8 @@ static void buildShardLevelInfo(
 
     static void fillDiskUsagePerNode(
         List<NodeStats> nodeStatsArray,
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvailableUsages,
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvailableUsages
+        Map<String, DiskUsage> newLeastAvailableUsages,
+        Map<String, DiskUsage> newMostAvailableUsages
     ) {
         for (NodeStats nodeStats : nodeStatsArray) {
             if (nodeStats.getFs() == null) {
@@ -534,18 +533,12 @@ static void fillDiskUsagePerNode(
     }
 
     private record IndicesStatsSummary(
-        ImmutableOpenMap<String, Long> shardSizes,
-        ImmutableOpenMap<ShardId, Long> shardDataSetSizes,
-        ImmutableOpenMap<ShardRouting, String> shardRoutingToDataPath,
-        ImmutableOpenMap<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
+        Map<String, Long> shardSizes,
+        Map<ShardId, Long> shardDataSetSizes,
+        Map<ShardRouting, String> shardRoutingToDataPath,
+        Map<ClusterInfo.NodeAndPath, ClusterInfo.ReservedSpace> reservedSpace
     ) {
-        static final IndicesStatsSummary EMPTY = new IndicesStatsSummary(
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of(),
-            ImmutableOpenMap.of()
-        );
-
+        static final IndicesStatsSummary EMPTY = new IndicesStatsSummary(Map.of(), Map.of(), Map.of(), Map.of());
     }
 
 }

server/src/test/java/org/elasticsearch/cluster/DiskUsageTests.java

@@ -17,7 +17,6 @@
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.ShardRoutingHelper;
 import org.elasticsearch.cluster.routing.UnassignedInfo;
-import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.index.Index;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.shard.ShardPath;
@@ -29,6 +28,7 @@
 import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.emptySet;
@@ -116,10 +116,9 @@ public void testFillShardLevelInfo() {
             new ShardStats(test_0, new ShardPath(false, test0Path, test0Path, test_0.shardId()), commonStats0, null, null, null),
             new ShardStats(test_1, new ShardPath(false, test1Path, test1Path, test_1.shardId()), commonStats1, null, null, null),
             new ShardStats(test_1, new ShardPath(false, test1Path, test1Path, test_1.shardId()), commonStats2, null, null, null) };
-        ImmutableOpenMap.Builder<String, Long> shardSizes = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<ShardId, Long> shardDataSetSizes = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<ShardRouting, String> routingToPath = ImmutableOpenMap.builder();
-        ClusterState state = ClusterState.builder(new ClusterName("blarg")).version(0).build();
+        Map<String, Long> shardSizes = new HashMap<>();
+        Map<ShardId, Long> shardDataSetSizes = new HashMap<>();
+        Map<ShardRouting, String> routingToPath = new HashMap<>();
         InternalClusterInfoService.buildShardLevelInfo(stats, shardSizes, shardDataSetSizes, routingToPath, new HashMap<>());
         assertEquals(2, shardSizes.size());
         assertTrue(shardSizes.containsKey(ClusterInfo.shardIdentifierFromRouting(test_0)));
@@ -141,8 +140,8 @@ public void testFillShardLevelInfo() {
     }
 
     public void testFillDiskUsage() {
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvaiableUsages = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvaiableUsages = ImmutableOpenMap.builder();
+        Map<String, DiskUsage> newLeastAvaiableUsages = new HashMap<>();
+        Map<String, DiskUsage> newMostAvaiableUsages = new HashMap<>();
         FsInfo.Path[] node1FSInfo = new FsInfo.Path[] {
             new FsInfo.Path("/middle", "/dev/sda", 100, 90, 80),
             new FsInfo.Path("/least", "/dev/sdb", 200, 190, 70),
@@ -229,8 +228,8 @@ public void testFillDiskUsage() {
     }
 
     public void testFillDiskUsageSomeInvalidValues() {
-        ImmutableOpenMap.Builder<String, DiskUsage> newLeastAvailableUsages = ImmutableOpenMap.builder();
-        ImmutableOpenMap.Builder<String, DiskUsage> newMostAvailableUsages = ImmutableOpenMap.builder();
+        Map<String, DiskUsage> newLeastAvailableUsages = new HashMap<>();
+        Map<String, DiskUsage> newMostAvailableUsages = new HashMap<>();
         FsInfo.Path[] node1FSInfo = new FsInfo.Path[] {
             new FsInfo.Path("/middle", "/dev/sda", 100, 90, 80),
             new FsInfo.Path("/least", "/dev/sdb", -1, -1, -1),