Release cached searcher

src/main/java/it/cavallium/dbengine/database/disk/CachedIndexSearcherManager.java

@@ -140,18 +140,18 @@ public class CachedIndexSearcherManager implements IndexSearcherManager {
 			return Mono.fromCallable(() -> {
 						activeSearchers.register();
 						IndexSearcher indexSearcher;
+						boolean decRef;
 						if (snapshot == null) {
 							indexSearcher = searcherManager.acquire();
+							decRef = true;
 						} else {
 							indexSearcher = snapshotsManager.resolveSnapshot(snapshot).getIndexSearcher();
+							decRef = false;
 						}
 						indexSearcher.setSimilarity(similarity);
 						assert indexSearcher.getIndexReader().getRefCount() > 0;
-						return indexSearcher;
+						return new LLIndexSearcher(indexSearcher, decRef, this::dropCachedIndexSearcher).send();
 					})
-					// todo: re-enable caching if needed
-					//.cacheInvalidateWhen(tuple -> onInvalidateCache)
-					.map(indexSearcher -> new LLIndexSearcher(indexSearcher, this::dropCachedIndexSearcher).send())
 					.takeUntilOther(onClose)
 					.doOnDiscard(Send.class, Send::close);
 		});

src/main/java/it/cavallium/dbengine/database/disk/LLIndexSearcher.java

@@ -2,23 +2,24 @@ package it.cavallium.dbengine.database.disk;
 
 import io.net5.buffer.api.Drop;
 import io.net5.buffer.api.Owned;
-import io.net5.buffer.api.internal.ResourceSupport;
 import it.cavallium.dbengine.database.LiveResourceSupport;
 import java.io.IOException;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.search.IndexSearcher;
-import org.apache.lucene.search.SearcherManager;
-import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 public class LLIndexSearcher extends LiveResourceSupport<LLIndexSearcher, LLIndexSearcher> {
 
-	private IndexSearcher indexSearcher;
+	private static final Logger logger = LoggerFactory.getLogger(LLIndexSearcher.class);
 
-	public LLIndexSearcher(IndexSearcher indexSearcher, Drop<LLIndexSearcher> drop) {
+	private IndexSearcher indexSearcher;
-		super(drop);
+	private final boolean decRef;
+
+	public LLIndexSearcher(IndexSearcher indexSearcher, boolean decRef, Drop<LLIndexSearcher> drop) {
+		super(new CloseOnDrop(drop));
 		this.indexSearcher = indexSearcher;
+		this.decRef = decRef;
 	}
 
 	public IndexReader getIndexReader() {
@@ -43,10 +44,33 @@ public class LLIndexSearcher extends LiveResourceSupport<LLIndexSearcher, LLInde
 	@Override
 	protected Owned<LLIndexSearcher> prepareSend() {
 		var indexSearcher = this.indexSearcher;
-		return drop -> new LLIndexSearcher(indexSearcher, drop);
+		return drop -> new LLIndexSearcher(indexSearcher, decRef, drop);
 	}
 
 	protected void makeInaccessible() {
 		this.indexSearcher = null;
 	}
+
+	private static class CloseOnDrop implements Drop<LLIndexSearcher> {
+
+		private final Drop<LLIndexSearcher> delegate;
+
+		public CloseOnDrop(Drop<LLIndexSearcher> drop) {
+			if (drop instanceof CloseOnDrop closeOnDrop) {
+				this.delegate = closeOnDrop.delegate;
+			} else {
+				this.delegate = drop;
+			}
+		}
+
+		@Override
+		public void drop(LLIndexSearcher obj) {
+			try {
+				obj.indexSearcher.getIndexReader().decRef();
+			} catch (IOException ex) {
+				logger.error("Failed to drop IndexReader", ex);
+			}
+			delegate.drop(obj);
+		}
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/searcher/SimpleUnsortedUnscoredLuceneMultiSearcher.java

@@ -43,7 +43,7 @@ public class SimpleUnsortedUnscoredLuceneMultiSearcher implements LuceneMultiSea
 				indexSearchers -> Flux
 						.fromIterable(indexSearchers.shards())
 						.flatMap(searcher -> {
-							var llSearcher = Mono.fromCallable(() -> new LLIndexSearcher(searcher, d -> {}).send());
+							var llSearcher = Mono.fromCallable(() -> new LLIndexSearcher(searcher, false, d -> {}).send());
 							return localSearcher.collect(llSearcher, localQueryParams, keyFieldName, transformer);
 						})
 						.collectList()