Remove track_live_docs_in_memory_bytes feature flag

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

@@ -301,26 +301,20 @@ protected static ShardFieldStats shardFieldStats(List<LeafReaderContext> leaves,
             } else {
                 usages = -1;
             }
-            boolean trackPostingsMemoryEnabled = isStateless;
-            boolean trackLiveDocsMemoryEnabled = ShardFieldStats.TRACK_LIVE_DOCS_IN_MEMORY_BYTES.isEnabled();
-            if (trackLiveDocsMemoryEnabled || trackPostingsMemoryEnabled) {
+            if (isStateless) {
                 SegmentReader segmentReader = Lucene.tryUnwrapSegmentReader(leaf.reader());
                 if (segmentReader != null) {
-                    if (trackPostingsMemoryEnabled) {
-                        String postingBytes = segmentReader.getSegmentInfo().info.getAttribute(
-                            TrackingPostingsInMemoryBytesCodec.IN_MEMORY_POSTINGS_BYTES_KEY
-                        );
-                        if (postingBytes != null) {
-                            totalPostingBytes += Long.parseLong(postingBytes);
-                        }
+                    String postingBytes = segmentReader.getSegmentInfo().info.getAttribute(
+                        TrackingPostingsInMemoryBytesCodec.IN_MEMORY_POSTINGS_BYTES_KEY
+                    );
+                    if (postingBytes != null) {
+                        totalPostingBytes += Long.parseLong(postingBytes);
                     }
-                    if (trackLiveDocsMemoryEnabled) {
-                        var liveDocs = segmentReader.getLiveDocs();
-                        if (liveDocs != null) {
-                            assert validateLiveDocsClass(liveDocs);
-                            long liveDocsBytes = getLiveDocsBytes(liveDocs);
-                            totalLiveDocsBytes += liveDocsBytes;
-                        }
+                    var liveDocs = segmentReader.getLiveDocs();
+                    if (liveDocs != null) {
+                        assert validateLiveDocsClass(liveDocs);
+                        long liveDocsBytes = getLiveDocsBytes(liveDocs);
+                        totalLiveDocsBytes += liveDocsBytes;
                     }
                 }
             }

server/src/main/java/org/elasticsearch/index/shard/ShardFieldStats.java

@@ -11,7 +11,6 @@
 
 import org.apache.lucene.util.FixedBitSet;
 import org.apache.lucene.util.RamUsageEstimator;
-import org.elasticsearch.common.util.FeatureFlag;
 
 /**
  * A per shard stats including the number of segments and total fields across those segments.
@@ -26,7 +25,6 @@
  */
 public record ShardFieldStats(int numSegments, int totalFields, long fieldUsages, long postingsInMemoryBytes, long liveDocsBytes) {
 
-    public static final FeatureFlag TRACK_LIVE_DOCS_IN_MEMORY_BYTES = new FeatureFlag("track_live_docs_in_memory_bytes");
     public static final long FIXED_BITSET_BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(FixedBitSet.class);
 
 }

server/src/test/java/org/elasticsearch/index/shard/IndexShardTests.java

@@ -27,7 +27,6 @@
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.Constants;
-import org.apache.lucene.util.FixedBitSet;
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.action.ActionListener;
@@ -78,7 +77,6 @@
 import org.elasticsearch.index.IndexModule;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.IndexVersion;
-import org.elasticsearch.index.MergePolicyConfig;
 import org.elasticsearch.index.codec.CodecService;
 import org.elasticsearch.index.engine.CommitStats;
 import org.elasticsearch.index.engine.DocIdSeqNoAndSource;
@@ -1981,71 +1979,6 @@ public void testShardFieldStats() throws IOException {
         closeShards(shard);
     }
 
-    public void testShardFieldStatsWithDeletes() throws IOException {
-        Settings settings = Settings.builder()
-            .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
-            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), TimeValue.MINUS_ONE)
-            .build();
-        IndexShard shard = newShard(true, settings);
-        assertNull(shard.getShardFieldStats());
-        recoverShardFromStore(shard);
-        boolean liveDocsTrackingEnabled = ShardFieldStats.TRACK_LIVE_DOCS_IN_MEMORY_BYTES.isEnabled();
-
-        // index some documents
-        int numDocs = 10;
-        for (int i = 0; i < numDocs; i++) {
-            indexDoc(shard, "_doc", "first_" + i, """
-                {
-                    "f1": "foo",
-                    "f2": "bar"
-                }
-                """);
-        }
-        shard.refresh("test");
-        var stats = shard.getShardFieldStats();
-        assertThat(stats.numSegments(), equalTo(1));
-        assertThat(stats.liveDocsBytes(), equalTo(0L));
-
-        // delete a doc
-        deleteDoc(shard, "first_0");
-
-        // Refresh and fetch new stats:
-        shard.refresh("test");
-        stats = shard.getShardFieldStats();
-        // More segments because delete operation is stored in the new segment for replication purposes.
-        assertThat(stats.numSegments(), equalTo(2));
-        long expectedLiveDocsSize = 0;
-        if (liveDocsTrackingEnabled) {
-            // Delete op is stored in new segment, but marked as deleted. All segements have live docs:
-            expectedLiveDocsSize += new FixedBitSet(numDocs).ramBytesUsed();
-            // Second segment the delete operation that is marked as deleted:
-            expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
-        }
-        assertThat(stats.liveDocsBytes(), equalTo(expectedLiveDocsSize));
-
-        // delete another doc:
-        deleteDoc(shard, "first_1");
-        shard.getMinRetainedSeqNo();
-
-        // Refresh and fetch new stats:
-        shard.refresh("test");
-        stats = shard.getShardFieldStats();
-        // More segments because delete operation is stored in the new segment for replication purposes.
-        assertThat(stats.numSegments(), equalTo(3));
-        expectedLiveDocsSize = 0;
-        if (liveDocsTrackingEnabled) {
-            // Delete op is stored in new segment, but marked as deleted. All segements have live docs:
-            // First segment with deletes
-            expectedLiveDocsSize += new FixedBitSet(numDocs).ramBytesUsed();
-            // Second and third segments the delete operation that is marked as deleted:
-            expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
-            expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
-        }
-        assertThat(stats.liveDocsBytes(), equalTo(expectedLiveDocsSize));
-
-        closeShards(shard);
-    }
-
     public void testIndexingOperationsListeners() throws IOException {
         IndexShard shard = newStartedShard(true);
         indexDoc(shard, "_doc", "0", "{\"foo\" : \"bar\"}");

server/src/test/java/org/elasticsearch/index/shard/LiveDocsEstimationTests.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the "Elastic License
+ * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
+ * Public License v 1"; you may not use this file except in compliance with, at
+ * your election, the "Elastic License 2.0", the "GNU Affero General Public
+ * License v3.0 only", or the "Server Side Public License, v 1".
+ */
+
+package org.elasticsearch.index.shard;
+
+import org.apache.lucene.util.FixedBitSet;
+import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.core.TimeValue;
+import org.elasticsearch.index.IndexSettings;
+import org.elasticsearch.index.MergePolicyConfig;
+
+import java.io.IOException;
+
+import static org.hamcrest.Matchers.equalTo;
+
+public class LiveDocsEstimationTests extends IndexShardTestCase {
+
+    @Override
+    protected Settings nodeSettings() {
+        return Settings.builder().put(DiscoveryNode.STATELESS_ENABLED_SETTING_NAME, true).build();
+    }
+
+    public void testShardFieldStatsWithDeletes() throws IOException {
+        Settings settings = Settings.builder()
+            .put(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
+            .put(IndexSettings.INDEX_REFRESH_INTERVAL_SETTING.getKey(), TimeValue.MINUS_ONE)
+            .build();
+        IndexShard shard = newShard(true, settings);
+        assertNull(shard.getShardFieldStats());
+        recoverShardFromStore(shard);
+
+        // index some documents
+        int numDocs = 10;
+        for (int i = 0; i < numDocs; i++) {
+            indexDoc(shard, "_doc", "first_" + i, """
+                {
+                    "f1": "foo",
+                    "f2": "bar"
+                }
+                """);
+        }
+        shard.refresh("test");
+        var stats = shard.getShardFieldStats();
+        assertThat(stats.numSegments(), equalTo(1));
+        assertThat(stats.liveDocsBytes(), equalTo(0L));
+
+        // delete a doc
+        deleteDoc(shard, "first_0");
+
+        // Refresh and fetch new stats:
+        shard.refresh("test");
+        stats = shard.getShardFieldStats();
+        // More segments because delete operation is stored in the new segment for replication purposes.
+        assertThat(stats.numSegments(), equalTo(2));
+        long expectedLiveDocsSize = 0;
+        // Delete op is stored in new segment, but marked as deleted. All segements have live docs:
+        expectedLiveDocsSize += new FixedBitSet(numDocs).ramBytesUsed();
+        // Second segment the delete operation that is marked as deleted:
+        expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
+        assertThat(stats.liveDocsBytes(), equalTo(expectedLiveDocsSize));
+
+        // delete another doc:
+        deleteDoc(shard, "first_1");
+        shard.getMinRetainedSeqNo();
+
+        // Refresh and fetch new stats:
+        shard.refresh("test");
+        stats = shard.getShardFieldStats();
+        // More segments because delete operation is stored in the new segment for replication purposes.
+        assertThat(stats.numSegments(), equalTo(3));
+        expectedLiveDocsSize = 0;
+        // Delete op is stored in new segment, but marked as deleted. All segements have live docs:
+        // First segment with deletes
+        expectedLiveDocsSize += new FixedBitSet(numDocs).ramBytesUsed();
+        // Second and third segments the delete operation that is marked as deleted:
+        expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
+        expectedLiveDocsSize += new FixedBitSet(1).ramBytesUsed();
+        assertThat(stats.liveDocsBytes(), equalTo(expectedLiveDocsSize));
+
+        closeShards(shard);
+    }
+
+}

test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java

@@ -616,7 +616,7 @@ protected IndexShard newShard(
         List<SearchOperationListener> soListener,
         IndexingOperationListener... listeners
     ) throws IOException {
-        final Settings nodeSettings = Settings.builder().put("node.name", routing.currentNodeId()).build();
+        final Settings nodeSettings = Settings.builder().put(nodeSettings()).put("node.name", routing.currentNodeId()).build();
         final IndexSettings indexSettings = new IndexSettings(indexMetadata, nodeSettings);
         final IndexShard indexShard;
         if (storeProvider == null) {
@@ -1336,4 +1336,8 @@ public static Engine.Warmer createTestWarmer(IndexSettings indexSettings) {
     public static long recoverLocallyUpToGlobalCheckpoint(IndexShard indexShard) {
         return safeAwait(indexShard::recoverLocallyUpToGlobalCheckpoint);
     }
+
+    protected Settings nodeSettings() {
+        return Settings.EMPTY;
+    }
 }