feature flagging of Zstandard

Signed-off-by: Sarthak Aggarwal <sarthagg@amazon.com>

Author: sarthakaggarwal97

CHANGELOG.md

@@ -151,6 +151,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Add support for wrapping CollectorManager with profiling during concurrent execution ([#9129](https://github.com/opensearch-project/OpenSearch/pull/9129))
 - Rethrow OpenSearch exception for non-concurrent path while using concurrent search ([#9177](https://github.com/opensearch-project/OpenSearch/pull/9177))
 - Improve performance of encoding composite keys in multi-term aggregations ([#9412](https://github.com/opensearch-project/OpenSearch/pull/9412))
+- Move support for ZStd compression behind a feature flag ([#9476](https://github.com/opensearch-project/OpenSearch/pull/9476))
 
 ### Deprecated
 
@@ -164,4 +165,4 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Security
 
 [Unreleased 3.0]: https://github.com/opensearch-project/OpenSearch/compare/2.x...HEAD
-[Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.10...2.x
+[Unreleased 2.x]: https://github.com/opensearch-project/OpenSearch/compare/2.10...2.x

distribution/src/config/opensearch.yml

@@ -129,3 +129,9 @@ ${path.logs}
 # index searcher threadpool.
 #
 #opensearch.experimental.feature.concurrent_segment_search.enabled: false
+#
+#
+# Gates the visibility of the ZStd compression algorithm features
+#  for indexing operations.
+#
+#opensearch.experimental.feature.compression.zstd.enabled: false

modules/reindex/src/internalClusterTest/java/org/opensearch/index/codec/MultiCodecReindexIT.java

@@ -15,6 +15,7 @@
 import org.opensearch.action.support.ActiveShardCount;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.engine.Segment;
 import org.opensearch.index.reindex.BulkByScrollResponse;
 import org.opensearch.index.reindex.ReindexAction;
@@ -40,6 +41,11 @@
 
 public class MultiCodecReindexIT extends ReindexTestCase {
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     public void testReindexingMultipleCodecs() throws InterruptedException, ExecutionException {
         internalCluster().ensureAtLeastNumDataNodes(1);
         Map<String, String> codecMap = Map.of(

server/src/internalClusterTest/java/org/opensearch/index/codec/CodecCompressionLevelIT.java

@@ -12,6 +12,7 @@
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
 import java.util.concurrent.ExecutionException;
@@ -21,6 +22,11 @@
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
 public class CodecCompressionLevelIT extends OpenSearchIntegTestCase {
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     public void testLuceneCodecsCreateIndexWithCompressionLevel() {
 
         internalCluster().ensureAtLeastNumDataNodes(1);

server/src/internalClusterTest/java/org/opensearch/index/codec/MultiCodecMergeIT.java

@@ -15,6 +15,7 @@
 import org.opensearch.action.admin.indices.settings.put.UpdateSettingsRequest;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.engine.Segment;
 import org.opensearch.test.OpenSearchIntegTestCase;
 
@@ -40,6 +41,11 @@
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST)
 public class MultiCodecMergeIT extends OpenSearchIntegTestCase {
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     public void testForceMergeMultipleCodecs() throws ExecutionException, InterruptedException {
 
         Map<String, String> codecMap = Map.of(

server/src/internalClusterTest/java/org/opensearch/indices/replication/SegmentReplicationIT.java

@@ -55,6 +55,7 @@
 import org.opensearch.common.lucene.index.OpenSearchDirectoryReader;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.core.common.io.stream.NamedWriteableRegistry;
 import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.index.IndexModule;
@@ -112,6 +113,11 @@
 @OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
 public class SegmentReplicationIT extends SegmentReplicationBaseIT {
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     @Before
     private void setup() {
         internalCluster().startClusterManagerOnlyNode();

server/src/internalClusterTest/java/org/opensearch/indices/stats/IndexStatsIT.java

@@ -55,6 +55,7 @@
 import org.opensearch.common.io.stream.BytesStreamOutput;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.core.action.support.DefaultShardOperationFailedException;
 import org.opensearch.core.common.bytes.BytesReference;
 import org.opensearch.core.common.io.stream.StreamOutput;
@@ -123,6 +124,11 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Collections.singleton(InternalSettingsPlugin.class);
     }
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     @Override
     protected Settings nodeSettings(int nodeOrdinal) {
         // Filter/Query cache is cleaned periodically, default is 60s, so make sure it runs often. Thread.sleep for 60s is bad

server/src/internalClusterTest/java/org/opensearch/recovery/TruncatedRecoveryIT.java

@@ -39,6 +39,7 @@
 import org.opensearch.action.index.IndexRequestBuilder;
 import org.opensearch.cluster.metadata.IndexMetadata;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.core.common.unit.ByteSizeUnit;
 import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.index.query.QueryBuilders;
@@ -72,6 +73,11 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(MockTransportService.TestPlugin.class, RecoverySettingsChunkSizePlugin.class);
     }
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     /**
      * This test tries to truncate some of larger files in the index to trigger leftovers on the recovery
      * target. This happens during recovery when the last chunk of the file is transferred to the replica

server/src/internalClusterTest/java/org/opensearch/search/suggest/CompletionSuggestSearchIT.java

@@ -47,6 +47,7 @@
 import org.opensearch.common.FieldMemoryStats;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.common.xcontent.XContentFactory;
 import org.opensearch.core.xcontent.XContentBuilder;
 import org.opensearch.index.mapper.MapperParsingException;
@@ -106,6 +107,11 @@ protected Collection<Class<? extends Plugin>> nodePlugins() {
         return Arrays.asList(InternalSettingsPlugin.class);
     }
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     public void testTieBreak() throws Exception {
         final CompletionMappingBuilder mapping = new CompletionMappingBuilder();
         mapping.indexAnalyzer("keyword");

server/src/internalClusterTest/java/org/opensearch/search/suggest/ContextCompletionSuggestSearchIT.java

@@ -40,6 +40,7 @@
 import org.opensearch.common.geo.GeoPoint;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.Fuzziness;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.core.rest.RestStatus;
 import org.opensearch.core.xcontent.ToXContent;
 import org.opensearch.core.xcontent.XContentBuilder;
@@ -74,6 +75,11 @@ public class ContextCompletionSuggestSearchIT extends OpenSearchIntegTestCase {
     private final String INDEX = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
     private final String FIELD = RandomStrings.randomAsciiOfLength(random(), 10).toLowerCase(Locale.ROOT);
 
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.ZSTD_COMPRESSION, "true").build();
+    }
+
     @Override
     protected int numberOfReplicas() {
         return 0;

server/src/main/java/org/opensearch/common/settings/FeatureFlagSettings.java

@@ -37,6 +37,7 @@ protected FeatureFlagSettings(
             Arrays.asList(
                 FeatureFlags.SEGMENT_REPLICATION_EXPERIMENTAL_SETTING,
                 FeatureFlags.REMOTE_STORE_SETTING,
+                FeatureFlags.ZSTD_COMPRESSION_SETTING,
                 FeatureFlags.EXTENSIONS_SETTING,
                 FeatureFlags.IDENTITY_SETTING,
                 FeatureFlags.CONCURRENT_SEGMENT_SEARCH_SETTING,

server/src/main/java/org/opensearch/common/util/FeatureFlags.java

@@ -21,6 +21,11 @@
  */
 public class FeatureFlags {
 
+    /**
+     * Gates the visibility of the index settings that allows the utilization of ZStd compression algorithm features for indexing operations.
+     */
+    public static final String ZSTD_COMPRESSION = "opensearch.experimental.feature.compression.zstd.enabled";
+
     /**
      * Gates the visibility of the segment replication experimental features that allows users to test unreleased beta features.
      */
@@ -96,6 +101,8 @@ public static boolean isEnabled(String featureFlagName) {
         Property.NodeScope
     );
 
+    public static final Setting<Boolean> ZSTD_COMPRESSION_SETTING = Setting.boolSetting(ZSTD_COMPRESSION, false, Property.NodeScope);
+
     public static final Setting<Boolean> REMOTE_STORE_SETTING = Setting.boolSetting(REMOTE_STORE, false, Property.NodeScope);
 
     public static final Setting<Boolean> EXTENSIONS_SETTING = Setting.boolSetting(EXTENSIONS, false, Property.NodeScope);

server/src/main/java/org/opensearch/index/codec/CodecService.java

@@ -37,7 +37,9 @@
 import org.apache.lucene.codecs.lucene95.Lucene95Codec;
 import org.apache.lucene.codecs.lucene95.Lucene95Codec.Mode;
 import org.opensearch.common.Nullable;
+import org.opensearch.common.annotation.ExperimentalApi;
 import org.opensearch.common.collect.MapBuilder;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.codec.customcodecs.ZstdCodec;
 import org.opensearch.index.codec.customcodecs.ZstdNoDictCodec;
@@ -67,7 +69,9 @@ public class CodecService {
      * the raw unfiltered lucene default. useful for testing
      */
     public static final String LUCENE_DEFAULT_CODEC = "lucene_default";
+    @ExperimentalApi
     public static final String ZSTD_CODEC = "zstd";
+    @ExperimentalApi
     public static final String ZSTD_NO_DICT_CODEC = "zstd_no_dict";
 
     public CodecService(@Nullable MapperService mapperService, IndexSettings indexSettings, Logger logger) {
@@ -79,15 +83,19 @@ public CodecService(@Nullable MapperService mapperService, IndexSettings indexSe
             codecs.put(LZ4, new Lucene95Codec());
             codecs.put(BEST_COMPRESSION_CODEC, new Lucene95Codec(Mode.BEST_COMPRESSION));
             codecs.put(ZLIB, new Lucene95Codec(Mode.BEST_COMPRESSION));
-            codecs.put(ZSTD_CODEC, new ZstdCodec(compressionLevel));
-            codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(compressionLevel));
+            if (FeatureFlags.isEnabled(FeatureFlags.ZSTD_COMPRESSION)) {
+                codecs.put(ZSTD_CODEC, new ZstdCodec(compressionLevel));
+                codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(compressionLevel));
+            }
         } else {
             codecs.put(DEFAULT_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
             codecs.put(LZ4, new PerFieldMappingPostingFormatCodec(Mode.BEST_SPEED, mapperService, logger));
             codecs.put(BEST_COMPRESSION_CODEC, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
             codecs.put(ZLIB, new PerFieldMappingPostingFormatCodec(Mode.BEST_COMPRESSION, mapperService, logger));
-            codecs.put(ZSTD_CODEC, new ZstdCodec(mapperService, logger, compressionLevel));
-            codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(mapperService, logger, compressionLevel));
+            if (FeatureFlags.isEnabled(FeatureFlags.ZSTD_COMPRESSION)) {
+                codecs.put(ZSTD_CODEC, new ZstdCodec(mapperService, logger, compressionLevel));
+                codecs.put(ZSTD_NO_DICT_CODEC, new ZstdNoDictCodec(mapperService, logger, compressionLevel));
+            }
         }
         codecs.put(LUCENE_DEFAULT_CODEC, Codec.getDefault());
         for (String codec : Codec.availableCodecs()) {

server/src/main/java/org/opensearch/index/engine/EngineConfig.java

@@ -45,6 +45,7 @@
 import org.opensearch.common.settings.Setting.Property;
 import org.opensearch.common.unit.MemorySizeValue;
 import org.opensearch.common.unit.TimeValue;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.core.common.unit.ByteSizeValue;
 import org.opensearch.core.index.shard.ShardId;
 import org.opensearch.core.indices.breaker.CircuitBreakerService;
@@ -133,9 +134,13 @@ public Supplier<RetentionLeases> retentionLeasesSupplier() {
             case "lz4":
             case "best_compression":
             case "zlib":
+            case "lucene_default":
+                return s;
             case "zstd":
             case "zstd_no_dict":
-            case "lucene_default":
+                if (FeatureFlags.isEnabled(FeatureFlags.ZSTD_COMPRESSION) == false) {
+                    throw new IllegalArgumentException("ZStandard feature must be enabled to set " + s + " codec.");
+                }
                 return s;
             default:
                 if (Codec.availableCodecs().contains(s) == false) { // we don't error message the not officially supported ones
@@ -183,6 +188,9 @@ private static void doValidateCodecSettings(final String codec) {
         switch (codec) {
             case "zstd":
             case "zstd_no_dict":
+                if (FeatureFlags.isEnabled(FeatureFlags.ZSTD_COMPRESSION) == false) {
+                    throw new IllegalArgumentException("Compression level cannot be set before enabling the ZStandard feature.");
+                }
                 return;
             case "best_compression":
             case "zlib":

server/src/test/java/org/opensearch/index/codec/CodecTests.java

@@ -45,6 +45,7 @@
 import org.apache.lucene.tests.util.LuceneTestCase.SuppressCodecs;
 import org.opensearch.common.settings.IndexScopedSettings;
 import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
 import org.opensearch.env.Environment;
 import org.opensearch.index.IndexSettings;
 import org.opensearch.index.analysis.IndexAnalyzers;
@@ -55,8 +56,10 @@
 import org.opensearch.index.similarity.SimilarityService;
 import org.opensearch.indices.mapper.MapperRegistry;
 import org.opensearch.plugins.MapperPlugin;
+import org.opensearch.test.FeatureFlagSetter;
 import org.opensearch.test.IndexSettingsModule;
 import org.opensearch.test.OpenSearchTestCase;
+import org.junit.Before;
 
 import java.io.IOException;
 import java.util.Collections;
@@ -67,6 +70,11 @@
 @SuppressCodecs("*") // we test against default codec so never get a random one here!
 public class CodecTests extends OpenSearchTestCase {
 
+    @Before
+    public void enableZstd() {
+        FeatureFlagSetter.set(FeatureFlags.ZSTD_COMPRESSION);
+    }
+
     public void testResolveDefaultCodecs() throws Exception {
         CodecService codecService = createCodecService(false);
         assertThat(codecService.codec("default"), instanceOf(PerFieldMappingPostingFormatCodec.class));
@@ -148,6 +156,20 @@ public void testBestCompressionWithCompressionLevel() {
         assertTrue(e.getMessage().startsWith("Compression level cannot be set"));
     }
 
+    public void testZstdFeatureFlag() {
+        FeatureFlagSetter.clear();
+        final Settings zstdSettings = Settings.builder()
+            .put(EngineConfig.INDEX_CODEC_SETTING.getKey(), randomFrom(CodecService.ZSTD_CODEC, CodecService.ZSTD_NO_DICT_CODEC))
+            .build();
+
+        IndexScopedSettings zstdIndexScopedSettings = new IndexScopedSettings(zstdSettings, IndexScopedSettings.BUILT_IN_INDEX_SETTINGS);
+        final IllegalArgumentException e = expectThrows(
+            IllegalArgumentException.class,
+            () -> zstdIndexScopedSettings.validate(zstdSettings, true)
+        );
+        assertTrue(e.getMessage().startsWith("ZStandard feature must be enabled to set"));
+    }
+
     public void testLuceneCodecsWithCompressionLevel() {
         String codecName = randomFrom(Codec.availableCodecs());
         Codec codec = Codec.forName(codecName);