Ignore 3x segment upgrade if unneeded

src/main/java/org/elasticsearch/index/engine/EngineConfig.java

@@ -152,7 +152,12 @@ public final class EngineConfig {
     /**
      * Creates a new {@link org.elasticsearch.index.engine.EngineConfig}
      */
-    public EngineConfig(ShardId shardId, boolean optimizeAutoGenerateId, ThreadPool threadPool, ShardIndexingService indexingService, IndexSettingsService indexSettingsService, IndicesWarmer warmer, Store store, SnapshotDeletionPolicy deletionPolicy, Translog translog, MergePolicyProvider mergePolicyProvider, MergeSchedulerProvider mergeScheduler, Analyzer analyzer, Similarity similarity, CodecService codecService, Engine.FailedEngineListener failedEngineListener) {
+    public EngineConfig(ShardId shardId, boolean optimizeAutoGenerateId, ThreadPool threadPool,
+                        ShardIndexingService indexingService, IndexSettingsService indexSettingsService,
+                        IndicesWarmer warmer, Store store, SnapshotDeletionPolicy deletionPolicy,
+                        Translog translog, MergePolicyProvider mergePolicyProvider,
+                        MergeSchedulerProvider mergeScheduler, Analyzer analyzer, Similarity similarity,
+                        CodecService codecService, Engine.FailedEngineListener failedEngineListener) {
         this.shardId = shardId;
         this.optimizeAutoGenerateId = optimizeAutoGenerateId;
         this.threadPool = threadPool;

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

@@ -31,6 +31,8 @@
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.IOUtils;
 import org.elasticsearch.ElasticsearchException;
+import org.elasticsearch.ElasticsearchIllegalStateException;
+import org.elasticsearch.Version;
 import org.elasticsearch.cluster.routing.operation.hash.djb.DjbHashFunction;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.lease.Releasable;
@@ -118,7 +120,20 @@ public InternalEngine(EngineConfig engineConfig) throws EngineException {
         boolean success = false;
         try {
             try {
-                upgrade3xSegments(store);
+                boolean autoUpgrade = true;
+                try {
+                    // If the index was created on 0.20.7 (Lucene 3.x) or earlier,
+                    // it needs to be upgraded
+                    autoUpgrade = Version.indexCreated(engineConfig.getIndexSettings()).onOrBefore(Version.V_0_20_7);
+                } catch (ElasticsearchIllegalStateException e) {
+                    // we weren't able to parse the version, that's fine
+                }
+                if (autoUpgrade) {
+                    logger.debug("[{}] checking for 3x segments to upgrade", shardId);
+                    upgrade3xSegments(store);
+                } else {
+                    logger.debug("[{}] skipping check for 3x segments", shardId);
+                }
             } catch (IOException ex) {
                 throw new EngineCreationFailureException(shardId, "failed to upgrade 3x segments", ex);
             }

src/main/java/org/elasticsearch/index/shard/IndexShard.java

@@ -57,7 +57,6 @@
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.AbstractRefCounted;
 import org.elasticsearch.common.util.concurrent.FutureUtils;
-import org.elasticsearch.env.NodeEnvironment;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.aliases.IndexAliasesService;
@@ -246,8 +245,9 @@ public IndexShard(ShardId shardId, @IndexSettings Settings indexSettings, IndexS
         /* create engine config */
         this.config = new EngineConfig(shardId,
                 indexSettings.getAsBoolean(EngineConfig.INDEX_OPTIMIZE_AUTOGENERATED_ID_SETTING, false),
-                threadPool, indexingService, indexSettingsService, warmer, store, deletionPolicy, translog, mergePolicyProvider, mergeScheduler,
-                analysisService.defaultIndexAnalyzer(), similarityService.similarity(), codecService, failedEngineListener);
+                threadPool, indexingService, indexSettingsService, warmer, store, deletionPolicy,
+                translog, mergePolicyProvider, mergeScheduler, analysisService.defaultIndexAnalyzer(),
+                similarityService.similarity(), codecService, failedEngineListener);
 
         logger.debug("state: [CREATED]");
 

src/test/java/org/elasticsearch/index/engine/InternalEngineTests.java

@@ -73,7 +73,6 @@
 import org.elasticsearch.index.settings.IndexSettingsService;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.store.DirectoryService;
-import org.elasticsearch.index.store.DirectoryUtils;
 import org.elasticsearch.index.store.Store;
 import org.elasticsearch.index.store.distributor.LeastUsedDistributor;
 import org.elasticsearch.index.translog.Translog;