address review

Author: jimczi

server/src/main/java/org/apache/lucene/index/ShuflleForcedMergePolicy.java renamed to server/src/main/java/org/apache/lucene/index/ShuffleForcedMergePolicy.java

@@ -34,10 +34,10 @@
  * and {@link MergePolicy#findForcedDeletesMerges}. This allows time-based indices, that usually have the eldest documents
  * first, to be efficient at finding the most recent documents too.
  */
-public class ShuflleForcedMergePolicy extends FilterMergePolicy {
+public class ShuffleForcedMergePolicy extends FilterMergePolicy {
     private static final String SHUFFLE_MERGE_KEY = "es.shuffle_merge";
 
-    public ShuflleForcedMergePolicy(MergePolicy in) {
+    public ShuffleForcedMergePolicy(MergePolicy in) {
         super(in);
     }
 
@@ -68,7 +68,7 @@ private MergeSpecification wrap(MergeSpecification mergeSpec) throws IOException
         }
         MergeSpecification newMergeSpec = new MergeSpecification();
         for (OneMerge toWrap : mergeSpec.merges) {
-            List<SegmentCommitInfo> newInfos = interleaveList(toWrap.segments);
+            List<SegmentCommitInfo> newInfos = interleaveList(new ArrayList<>(toWrap.segments));
             newMergeSpec.add(new OneMerge(newInfos) {
                 @Override
                 public CodecReader wrapForMerge(CodecReader reader) throws IOException {

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

@@ -36,7 +36,7 @@
 import org.apache.lucene.index.MergePolicy;
 import org.apache.lucene.index.SegmentCommitInfo;
 import org.apache.lucene.index.SegmentInfos;
-import org.apache.lucene.index.ShuflleForcedMergePolicy;
+import org.apache.lucene.index.ShuffleForcedMergePolicy;
 import org.apache.lucene.index.SoftDeletesRetentionMergePolicy;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocIdSetIterator;
@@ -57,6 +57,7 @@
 import org.elasticsearch.Assertions;
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.action.index.IndexRequest;
+import org.elasticsearch.common.Booleans;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.SuppressForbidden;
 import org.elasticsearch.common.lease.Releasable;
@@ -2225,10 +2226,13 @@ private IndexWriterConfig getIndexWriterConfig() {
                 new SoftDeletesRetentionMergePolicy(Lucene.SOFT_DELETES_FIELD, softDeletesPolicy::getRetentionQuery,
                     new PrunePostingsMergePolicy(mergePolicy, IdFieldMapper.NAME)));
         }
-        // We wrap the merge policy for all indices even though it is mostly useful for time-based indices
-        // but there should be no overhead for other type of indices so it's simpler than adding a setting
-        // to enable it.
-        mergePolicy = new ShuflleForcedMergePolicy(mergePolicy);
+        boolean shuffleForcedMerge = Booleans.parseBoolean(System.getProperty("es.shuffle_forced_merge", Boolean.TRUE.toString()));
+        if (shuffleForcedMerge) {
+            // We wrap the merge policy for all indices even though it is mostly useful for time-based indices
+            // but there should be no overhead for other type of indices so it's simpler than adding a setting
+            // to enable it.
+            mergePolicy = new ShuffleForcedMergePolicy(mergePolicy);
+        }
         iwc.setMergePolicy(new ElasticsearchMergePolicy(mergePolicy));
         iwc.setSimilarity(engineConfig.getSimilarity());
         iwc.setRAMBufferSizeMB(engineConfig.getIndexingBufferSize().getMbFrac());

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

@@ -61,6 +61,11 @@ public ElasticsearchMergePolicy(MergePolicy delegate) {
         super(delegate);
     }
 
+    /** return the wrapped merge policy */
+    public MergePolicy getDelegate() {
+        return in;
+    }
+
     private boolean shouldUpgrade(SegmentCommitInfo info) {
         org.apache.lucene.util.Version old = info.info.getVersion();
         org.apache.lucene.util.Version cur = Version.CURRENT.luceneVersion;

server/src/test/java/org/apache/lucene/index/ShuffleForcedMergePolicyTests.java

@@ -37,7 +37,7 @@ public class ShuffleForcedMergePolicyTests extends BaseMergePolicyTestCase {
     public void testDiagnostics() throws IOException {
         try (Directory dir = newDirectory()) {
             IndexWriterConfig iwc = newIndexWriterConfig();
-            MergePolicy mp = new ShuflleForcedMergePolicy(newLogMergePolicy());
+            MergePolicy mp = new ShuffleForcedMergePolicy(newLogMergePolicy());
             iwc.setMergePolicy(mp);
             boolean sorted = random().nextBoolean();
             if (sorted) {
@@ -58,14 +58,14 @@ public void testDiagnostics() throws IOException {
                 try (DirectoryReader reader = DirectoryReader.open(writer)) {
                     assertThat(reader.leaves().size(), greaterThan(2));
                     assertSegmentReaders(reader, leaf -> {
-                        assertFalse(ShuflleForcedMergePolicy.isInterleavedSegment(leaf));
+                        assertFalse(ShuffleForcedMergePolicy.isInterleavedSegment(leaf));
                     });
                 }
                 writer.forceMerge(1);
                 try (DirectoryReader reader = DirectoryReader.open(writer)) {
                     assertThat(reader.leaves().size(), equalTo(1));
                     assertSegmentReaders(reader, leaf -> {
-                        assertTrue(ShuflleForcedMergePolicy.isInterleavedSegment(leaf));
+                        assertTrue(ShuffleForcedMergePolicy.isInterleavedSegment(leaf));
                     });
                 }
             }
@@ -80,7 +80,7 @@ private void assertSegmentReaders(DirectoryReader reader, Consumer<LeafReader> c
 
     @Override
     protected MergePolicy mergePolicy() {
-        return new ShuflleForcedMergePolicy(newLogMergePolicy());
+        return new ShuffleForcedMergePolicy(newLogMergePolicy());
     }
 
     @Override

server/src/test/java/org/elasticsearch/index/engine/PrunePostingsMergePolicyTests.java

@@ -29,7 +29,7 @@
 import org.apache.lucene.index.LeafReader;
 import org.apache.lucene.index.MergePolicy;
 import org.apache.lucene.index.NumericDocValues;
-import org.apache.lucene.index.ShuflleForcedMergePolicy;
+import org.apache.lucene.index.ShuffleForcedMergePolicy;
 import org.apache.lucene.index.SoftDeletesRetentionMergePolicy;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.index.Terms;
@@ -52,7 +52,7 @@ public void testPrune() throws IOException {
             iwc.setSoftDeletesField("_soft_deletes");
             MergePolicy mp = new SoftDeletesRetentionMergePolicy("_soft_deletes", MatchAllDocsQuery::new,
                 new PrunePostingsMergePolicy(newLogMergePolicy(), "id"));
-            iwc.setMergePolicy(new ShuflleForcedMergePolicy(mp));
+            iwc.setMergePolicy(new ShuffleForcedMergePolicy(mp));
             boolean sorted = randomBoolean();
             if (sorted) {
                 iwc.setIndexSort(new Sort(new SortField("sort", SortField.Type.INT)));

server/src/test/java/org/elasticsearch/index/engine/RecoverySourcePruneMergePolicyTests.java

@@ -34,7 +34,7 @@
 import org.apache.lucene.index.NumericDocValues;
 import org.apache.lucene.index.SegmentCommitInfo;
 import org.apache.lucene.index.SegmentInfos;
-import org.apache.lucene.index.ShuflleForcedMergePolicy;
+import org.apache.lucene.index.ShuffleForcedMergePolicy;
 import org.apache.lucene.index.StandardDirectoryReader;
 import org.apache.lucene.index.Term;
 import org.apache.lucene.search.DocIdSetIterator;
@@ -58,7 +58,7 @@ public void testPruneAll() throws IOException {
             IndexWriterConfig iwc = newIndexWriterConfig();
             RecoverySourcePruneMergePolicy mp = new RecoverySourcePruneMergePolicy("extra_source", MatchNoDocsQuery::new,
                 newLogMergePolicy());
-            iwc.setMergePolicy(new ShuflleForcedMergePolicy(mp));
+            iwc.setMergePolicy(new ShuffleForcedMergePolicy(mp));
             try (IndexWriter writer = new IndexWriter(dir, iwc)) {
                 for (int i = 0; i < 20; i++) {
                     if (i > 0 && randomBoolean()) {