Close LMDB databases after each full search

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

@@ -76,4 +76,9 @@ public class LLTempLMDBEnv implements Closeable {
 				.map(Path::toFile)
 				.forEach(File::delete);
 	}
+
+	public int countUsedDbs() {
+		var freeIds = this.freeIds.cardinality();
+		return MAX_DATABASES - freeIds;
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/CloseableIterable.java

@@ -1,11 +1,12 @@
 package it.cavallium.dbengine.lucene;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Iterator;
 import org.jetbrains.annotations.NotNull;
 
-public interface CloseableIterable<T> extends Iterable<T>, Closeable {
+public interface CloseableIterable<T> extends Iterable<T>, SafeCloseable {
 
 	@Override
 	void close();

src/main/java/it/cavallium/dbengine/lucene/EmptyPriorityQueue.java

@@ -49,7 +49,7 @@ public class EmptyPriorityQueue<T> implements PriorityQueue<T> {
 	}
 
 	@Override
-	public void close() throws IOException {
+	public void close() {
 
 	}
 }

src/main/java/it/cavallium/dbengine/lucene/FullDocs.java

@@ -4,6 +4,7 @@ import static it.cavallium.dbengine.lucene.LLDocElementScoreComparator.SCORE_DOC
 import static org.apache.lucene.search.TotalHits.Relation.*;
 
 import it.cavallium.dbengine.lucene.collector.FullFieldDocs;
+import java.io.IOException;
 import java.util.Comparator;
 import org.apache.lucene.search.FieldComparator;
 import org.apache.lucene.search.Sort;
@@ -31,6 +32,13 @@ public interface FullDocs<T extends LLDoc> extends ResourceIterable<T> {
 		ResourceIterable<T> mergedIterable = mergeResourceIterable(sort, fullDocs);
 		TotalHits mergedTotalHits = mergeTotalHits(fullDocs);
 		FullDocs<T> docs = new FullDocs<>() {
+			@Override
+			public void close() {
+				for (FullDocs<T> fullDoc : fullDocs) {
+					fullDoc.close();
+				}
+			}
+
 			@Override
 			public Flux<T> iterate() {
 				return mergedIterable.iterate();
@@ -70,77 +78,85 @@ public interface FullDocs<T extends LLDoc> extends ResourceIterable<T> {
 	static <T extends LLDoc> ResourceIterable<T> mergeResourceIterable(
 			@Nullable Sort sort,
 			FullDocs<T>[] fullDocs) {
-		return () -> {
-			@SuppressWarnings("unchecked")
-			Flux<T>[] iterables = new Flux[fullDocs.length];
-
-			for (int i = 0; i < fullDocs.length; i++) {
-				var singleFullDocs = fullDocs[i].iterate();
-				iterables[i] = singleFullDocs;
+		return new ResourceIterable<T>() {
+			@Override
+			public void close() {
+				for (FullDocs<T> fullDoc : fullDocs) {
+					fullDoc.close();
+				}
 			}
 
-			Comparator<LLDoc> comp;
-			if (sort == null) {
-				// Merge maintaining sorting order (Algorithm taken from TopDocs.ScoreMergeSortQueue)
+			@Override
+			public Flux<T> iterate() {
+				@SuppressWarnings("unchecked") Flux<T>[] iterables = new Flux[fullDocs.length];
 
-				comp = SCORE_DOC_SCORE_ELEM_COMPARATOR.thenComparing(DEFAULT_TIE_BREAKER);
-			} else {
-				// Merge maintaining sorting order (Algorithm taken from TopDocs.MergeSortQueue)
-
-				SortField[] sortFields = sort.getSort();
-				var comparators = new FieldComparator[sortFields.length];
-				var reverseMul = new int[sortFields.length];
-
-				for(int compIDX = 0; compIDX < sortFields.length; ++compIDX) {
-					SortField sortField = sortFields[compIDX];
-					comparators[compIDX] = sortField.getComparator(1, compIDX);
-					reverseMul[compIDX] = sortField.getReverse() ? -1 : 1;
+				for (int i = 0; i < fullDocs.length; i++) {
+					var singleFullDocs = fullDocs[i].iterate();
+					iterables[i] = singleFullDocs;
 				}
 
-				comp = (first, second) -> {
-					assert first != second;
+				Comparator<LLDoc> comp;
+				if (sort == null) {
+					// Merge maintaining sorting order (Algorithm taken from TopDocs.ScoreMergeSortQueue)
 
-					LLFieldDoc firstFD = (LLFieldDoc) first;
-					LLFieldDoc secondFD = (LLFieldDoc) second;
+					comp = SCORE_DOC_SCORE_ELEM_COMPARATOR.thenComparing(DEFAULT_TIE_BREAKER);
+				} else {
+					// Merge maintaining sorting order (Algorithm taken from TopDocs.MergeSortQueue)
 
-					for(int compIDX = 0; compIDX < comparators.length; ++compIDX) {
-						//noinspection rawtypes
-						FieldComparator fieldComp = comparators[compIDX];
-						//noinspection unchecked
-						int cmp = reverseMul[compIDX] * fieldComp.compareValues(firstFD.fields().get(compIDX), secondFD.fields().get(compIDX));
-						if (cmp != 0) {
-							return cmp;
+					SortField[] sortFields = sort.getSort();
+					var comparators = new FieldComparator[sortFields.length];
+					var reverseMul = new int[sortFields.length];
+
+					for (int compIDX = 0; compIDX < sortFields.length; ++compIDX) {
+						SortField sortField = sortFields[compIDX];
+						comparators[compIDX] = sortField.getComparator(1, compIDX);
+						reverseMul[compIDX] = sortField.getReverse() ? -1 : 1;
+					}
+
+					comp = (first, second) -> {
+						assert first != second;
+
+						LLFieldDoc firstFD = (LLFieldDoc) first;
+						LLFieldDoc secondFD = (LLFieldDoc) second;
+
+						for (int compIDX = 0; compIDX < comparators.length; ++compIDX) {
+							//noinspection rawtypes
+							FieldComparator fieldComp = comparators[compIDX];
+							//noinspection unchecked
+							int cmp = reverseMul[compIDX] * fieldComp.compareValues(firstFD.fields().get(compIDX),
+									secondFD.fields().get(compIDX)
+							);
+							if (cmp != 0) {
+								return cmp;
+							}
 						}
-					}
 
-					return tieBreakCompare(first, second, DEFAULT_TIE_BREAKER);
-				};
-			}
-
-			@SuppressWarnings("unchecked")
-			Flux<T>[] fluxes = new Flux[fullDocs.length];
-			for (int i = 0; i < iterables.length; i++) {
-				var shardIndex = i;
-				fluxes[i] = iterables[i].<T>map(shard -> {
-					if (shard instanceof LLScoreDoc scoreDoc) {
-						//noinspection unchecked
-						return (T) new LLScoreDoc(scoreDoc.doc(), scoreDoc.score(), shardIndex);
-					} else if (shard instanceof LLFieldDoc fieldDoc) {
-						//noinspection unchecked
-						return (T) new LLFieldDoc(fieldDoc.doc(), fieldDoc.score(), shardIndex, fieldDoc.fields());
-					} else if (shard instanceof LLSlotDoc slotDoc) {
-						//noinspection unchecked
-						return (T) new LLSlotDoc(slotDoc.doc(), slotDoc.score(), shardIndex, slotDoc.slot());
-					} else {
-						throw new UnsupportedOperationException("Unsupported type " + shard.getClass());
-					}
-				});
-				if (fullDocs[i].totalHits().relation == EQUAL_TO) {
-					fluxes[i] = fluxes[i].take(fullDocs[i].totalHits().value, true);
+						return tieBreakCompare(first, second, DEFAULT_TIE_BREAKER);
+					};
 				}
-			}
 
-			return Flux.mergeComparing(comp, fluxes);
+				@SuppressWarnings("unchecked") Flux<T>[] fluxes = new Flux[fullDocs.length];
+				for (int i = 0; i < iterables.length; i++) {
+					var shardIndex = i;
+					fluxes[i] = iterables[i].<T>map(shard -> switch (shard) {
+						case LLScoreDoc scoreDoc ->
+								//noinspection unchecked
+								(T) new LLScoreDoc(scoreDoc.doc(), scoreDoc.score(), shardIndex);
+						case LLFieldDoc fieldDoc ->
+								//noinspection unchecked
+								(T) new LLFieldDoc(fieldDoc.doc(), fieldDoc.score(), shardIndex, fieldDoc.fields());
+						case LLSlotDoc slotDoc ->
+								//noinspection unchecked
+								(T) new LLSlotDoc(slotDoc.doc(), slotDoc.score(), shardIndex, slotDoc.slot());
+						case null, default -> throw new UnsupportedOperationException("Unsupported type " + (shard == null ? null : shard.getClass()));
+					});
+					if (fullDocs[i].totalHits().relation == EQUAL_TO) {
+						fluxes[i] = fluxes[i].take(fullDocs[i].totalHits().value, true);
+					}
+				}
+
+				return Flux.mergeComparing(comp, fluxes);
+			}
 		};
 	}
 

src/main/java/it/cavallium/dbengine/lucene/LLSlotDocCodec.java

@@ -1,7 +1,9 @@
 package it.cavallium.dbengine.lucene;
 
 import io.net5.buffer.ByteBuf;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
+import java.io.Closeable;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
@@ -14,7 +16,7 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.search.Sort;
 import org.apache.lucene.search.SortField;
 
-public class LLSlotDocCodec implements LMDBSortedCodec<LLSlotDoc>, FieldValueHitQueue {
+public class LLSlotDocCodec implements LMDBSortedCodec<LLSlotDoc>, FieldValueHitQueue, SafeCloseable {
 
 	private final SortField[] fields;
 
@@ -166,4 +168,13 @@ public class LLSlotDocCodec implements LMDBSortedCodec<LLSlotDoc>, FieldValueHit
 	public SortField[] getFields() {
 		return fields;
 	}
+
+	@Override
+	public void close() {
+		for (FieldComparator<?> comparator : this.comparators) {
+			if (comparator instanceof SafeCloseable closeable) {
+				closeable.close();
+			}
+		}
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/LMDBArray.java

@@ -5,6 +5,7 @@ import static org.lmdbjava.DbiFlags.MDB_CREATE;
 import io.net5.buffer.ByteBuf;
 import io.net5.buffer.PooledByteBufAllocator;
 import it.cavallium.dbengine.database.LLUtils;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
 import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
@@ -23,7 +24,7 @@ import org.lmdbjava.Dbi;
 import org.lmdbjava.Env;
 import org.lmdbjava.Txn;
 
-public class LMDBArray<V> implements IArray<V>, Closeable {
+public class LMDBArray<V> implements IArray<V>, SafeCloseable {
 
 
 	private final AtomicBoolean closed = new AtomicBoolean();
@@ -238,7 +239,7 @@ public class LMDBArray<V> implements IArray<V>, Closeable {
 	}
 
 	@Override
-	public void close() throws IOException {
+	public void close() {
 		if (closed.compareAndSet(false, true)) {
 			ensureThread();
 			for (ByteBuf value : toWrite.values()) {

src/main/java/it/cavallium/dbengine/lucene/LMDBPriorityQueue.java

@@ -5,7 +5,9 @@ import static org.lmdbjava.DbiFlags.*;
 import io.net5.buffer.ByteBuf;
 import io.net5.buffer.PooledByteBufAllocator;
 import it.cavallium.dbengine.database.LLUtils;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
+import java.io.Closeable;
 import java.io.IOException;
 import java.util.ArrayDeque;
 import java.util.Deque;
@@ -77,6 +79,7 @@ public class LMDBPriorityQueue<T> implements PriorityQueue<T>, Reversable<Revers
 	}
 
 	private void switchToMode(boolean write, boolean wantCursor) {
+		assert !closed.get() : "Closed";
 		if (iterating) {
 			throw new IllegalStateException("Tried to " + (write ? "write" : "read") + " while still iterating");
 		}
@@ -107,6 +110,7 @@ public class LMDBPriorityQueue<T> implements PriorityQueue<T>, Reversable<Revers
 	}
 
 	private void switchToModeUncached(boolean write, boolean wantCursor) {
+		assert !closed.get() : "Closed";
 		if (iterating) {
 			throw new IllegalStateException("Tried to " + (write ? "write" : "read") + " while still iterating");
 		}
@@ -497,7 +501,7 @@ public class LMDBPriorityQueue<T> implements PriorityQueue<T>, Reversable<Revers
 	}
 
 	@Override
-	public void close() throws IOException {
+	public void close() {
 		if (closed.compareAndSet(false, true)) {
 			ensureThread();
 			for (ByteBuf toWriteKey : toWriteKeys) {
@@ -523,6 +527,9 @@ public class LMDBPriorityQueue<T> implements PriorityQueue<T>, Reversable<Revers
 			}
 			lmdb.close();
 			this.tempEnv.freeDb(lmdbDbId);
+			if (this.codec instanceof SafeCloseable closeable) {
+				closeable.close();
+			}
 		}
 	}
 
@@ -536,6 +543,11 @@ public class LMDBPriorityQueue<T> implements PriorityQueue<T>, Reversable<Revers
 	@Override
 	public ReversableResourceIterable<T> reverse() {
 		return new ReversableResourceIterable<>() {
+			@Override
+			public void close() {
+				LMDBPriorityQueue.this.close();
+			}
+
 			@Override
 			public Flux<T> iterate() {
 				return reverseIterate();

src/main/java/it/cavallium/dbengine/lucene/LazyFullDocs.java

@@ -1,5 +1,7 @@
 package it.cavallium.dbengine.lucene;
 
+import java.io.Closeable;
+import java.io.IOException;
 import org.apache.lucene.search.TotalHits;
 import reactor.core.publisher.Flux;
 
@@ -27,4 +29,9 @@ public class LazyFullDocs<T extends LLDoc> implements FullDocs<T> {
 	public TotalHits totalHits() {
 		return totalHits;
 	}
+
+	@Override
+	public void close() {
+		pq.close();
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/PriorityQueue.java

@@ -1,8 +1,8 @@
 package it.cavallium.dbengine.lucene;
 
-import java.io.Closeable;
+import it.cavallium.dbengine.database.SafeCloseable;
 
-public interface PriorityQueue<T> extends ResourceIterable<T>, Closeable {
+public interface PriorityQueue<T> extends ResourceIterable<T>, SafeCloseable {
 
 	/**
 	 * Adds an Object to a PriorityQueue in log(size) time. If one tries to add more objects than maxSize from initialize

src/main/java/it/cavallium/dbengine/lucene/ResourceIterable.java

@@ -1,10 +1,12 @@
 package it.cavallium.dbengine.lucene;
 
+import it.cavallium.dbengine.database.SafeCloseable;
+import java.io.Closeable;
 import java.util.Iterator;
 import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Flux;
 
-public interface ResourceIterable<T> {
+public interface ResourceIterable<T> extends SafeCloseable {
 
 	/**
 	 * Iterate this PriorityQueue

src/main/java/it/cavallium/dbengine/lucene/collector/FullDocsCollector.java

@@ -16,6 +16,7 @@
  */
 package it.cavallium.dbengine.lucene.collector;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.lucene.FullDocs;
 import it.cavallium.dbengine.lucene.LLDoc;
 import it.cavallium.dbengine.lucene.LazyFullDocs;
@@ -38,7 +39,7 @@ import org.apache.lucene.search.TotalHits;
  * all methods, in order to avoid a NullPointerException.
  */
 public abstract class FullDocsCollector<PQ extends PriorityQueue<INTERNAL> & Reversable<ReversableResourceIterable<INTERNAL>>, INTERNAL extends LLDoc,
-		EXTERNAL extends LLDoc> implements Collector, AutoCloseable {
+		EXTERNAL extends LLDoc> implements Collector, SafeCloseable {
 
 	/**
 	 * The priority queue which holds the top documents. Note that different implementations of
@@ -71,7 +72,7 @@ public abstract class FullDocsCollector<PQ extends PriorityQueue<INTERNAL> & Rev
 	public abstract ResourceIterable<EXTERNAL> mapResults(ResourceIterable<INTERNAL> it);
 
 	@Override
-	public void close() throws Exception {
+	public void close() {
 		pq.close();
 	}
 }

src/main/java/it/cavallium/dbengine/lucene/collector/FullFieldDocs.java

@@ -1,13 +1,16 @@
 package it.cavallium.dbengine.lucene.collector;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.lucene.FullDocs;
 import it.cavallium.dbengine.lucene.LLDoc;
 import it.cavallium.dbengine.lucene.LLFieldDoc;
+import java.io.Closeable;
+import java.io.IOException;
 import org.apache.lucene.search.SortField;
 import org.apache.lucene.search.TotalHits;
 import reactor.core.publisher.Flux;
 
-public class FullFieldDocs<T extends LLDoc> implements FullDocs<T> {
+public class FullFieldDocs<T extends LLDoc> implements FullDocs<T>, SafeCloseable {
 
 	private final FullDocs<T> fullDocs;
 	private final SortField[] fields;
@@ -35,4 +38,9 @@ public class FullFieldDocs<T extends LLDoc> implements FullDocs<T> {
 	public SortField[] fields() {
 		return fields;
 	}
+
+	@Override
+	public void close() {
+		fullDocs.close();
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/collector/LMDBFullFieldDocCollector.java

@@ -16,6 +16,7 @@
  */
 package it.cavallium.dbengine.lucene.collector;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.FieldValueHitQueue;
 import it.cavallium.dbengine.lucene.FullDocs;
@@ -26,6 +27,7 @@ import it.cavallium.dbengine.lucene.LMDBPriorityQueue;
 import it.cavallium.dbengine.lucene.MaxScoreAccumulator;
 import it.cavallium.dbengine.lucene.PriorityQueue;
 import it.cavallium.dbengine.lucene.ResourceIterable;
+import java.io.Closeable;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
@@ -55,8 +57,7 @@ import reactor.core.publisher.Flux;
  * <a href="https://github.com/apache/lucene/commits/main/lucene/core/src/java/org/apache/lucene/search/TopFieldCollector.java">
  *   Lucene TopFieldCollector changes on GitHub</a>
  */
-public abstract class LMDBFullFieldDocCollector
-		extends FullDocsCollector<LMDBPriorityQueue<LLSlotDoc>, LLSlotDoc, LLFieldDoc> {
+public abstract class LMDBFullFieldDocCollector extends FullDocsCollector<LMDBPriorityQueue<LLSlotDoc>, LLSlotDoc, LLFieldDoc> {
 
 	// TODO: one optimization we could do is to pre-fill
 	// the queue with sentinel value that guaranteed to
@@ -239,6 +240,11 @@ public abstract class LMDBFullFieldDocCollector
 		@Override
 		public ResourceIterable<LLFieldDoc> mapResults(ResourceIterable<LLSlotDoc> it) {
 			return new ResourceIterable<>() {
+				@Override
+				public void close() {
+					it.close();
+				}
+
 				@Override
 				public Flux<LLFieldDoc> iterate() {
 					return it.iterate().map(fieldValueHitQueue::fillFields);
@@ -469,4 +475,13 @@ public abstract class LMDBFullFieldDocCollector
 	public boolean isEarlyTerminated() {
 		return totalHitsRelation == Relation.GREATER_THAN_OR_EQUAL_TO;
 	}
+
+	@Override
+	public void close() {
+		this.pq.close();
+		if (this.firstComparator instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+		super.close();
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/collector/LMDBFullScoreDocCollector.java

@@ -316,4 +316,5 @@ public abstract class LMDBFullScoreDocCollector extends FullDocsCollector<LMDBPr
 			}
 		}
 	}
+
 }

src/main/java/it/cavallium/dbengine/lucene/comparators/DocComparator.java

@@ -17,12 +17,14 @@
 
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.IntCodec;
 import it.cavallium.dbengine.lucene.LMDBArray;
 import it.cavallium.dbengine.lucene.LMDBPriorityQueue;
 import it.cavallium.dbengine.lucene.LongCodec;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.search.DocIdSetIterator;
@@ -34,7 +36,7 @@ import org.apache.lucene.search.Scorable;
  * Comparator that sorts by asc _doc
  * Based on {@link org.apache.lucene.search.comparators.DocComparator}
  * */
-public class DocComparator extends FieldComparator<Integer> {
+public class DocComparator extends FieldComparator<Integer> implements SafeCloseable {
   private final IArray<Integer> docIDs;
   private final boolean enableSkipping; // if skipping functionality should be enabled
   private int bottom;
@@ -75,7 +77,14 @@ public class DocComparator extends FieldComparator<Integer> {
     return docIDs.getOrDefault(slot, 0);
   }
 
-  /**
+	@Override
+	public void close() {
+		if (docIDs instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
+
+	/**
    * DocLeafComparator with skipping functionality. When sort by _doc asc, after collecting top N
    * matches and enough hits, the comparator can skip all the following documents. When sort by _doc
    * asc and "top" document is set after which search should start, the comparator provides an

src/main/java/it/cavallium/dbengine/lucene/comparators/DoubleComparator.java

@@ -17,11 +17,13 @@
 
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.DoubleCodec;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.LMDBArray;
 import it.cavallium.dbengine.lucene.SortFieldCodec;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.document.DoublePoint;
 import org.apache.lucene.index.LeafReaderContext;
@@ -32,7 +34,7 @@ import org.apache.lucene.search.LeafFieldComparator;
  * skipping functionality - an iterator that can skip over non-competitive documents.
  * Based on {@link org.apache.lucene.search.comparators.DoubleComparator}
  */
-public class DoubleComparator extends NumericComparator<Double> {
+public class DoubleComparator extends NumericComparator<Double> implements SafeCloseable {
   private final IArray<Double> values;
   protected double topValue;
   protected double bottom;
@@ -64,7 +66,14 @@ public class DoubleComparator extends NumericComparator<Double> {
     return new DoubleLeafComparator(context);
   }
 
-  /** Leaf comparator for {@link DoubleComparator} that provides skipping functionality */
+	@Override
+	public void close() {
+		if (values instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
+
+	/** Leaf comparator for {@link DoubleComparator} that provides skipping functionality */
   public class DoubleLeafComparator extends NumericLeafComparator {
 
     public DoubleLeafComparator(LeafReaderContext context) throws IOException {

src/main/java/it/cavallium/dbengine/lucene/comparators/FloatComparator.java

@@ -17,11 +17,13 @@
 
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.DoubleCodec;
 import it.cavallium.dbengine.lucene.FloatCodec;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.LMDBArray;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.document.FloatPoint;
 import org.apache.lucene.index.LeafReaderContext;
@@ -32,7 +34,7 @@ import org.apache.lucene.search.LeafFieldComparator;
  * skipping functionality – an iterator that can skip over non-competitive documents.
  * Based on {@link org.apache.lucene.search.comparators.FloatComparator}
  */
-public class FloatComparator extends NumericComparator<Float> {
+public class FloatComparator extends NumericComparator<Float> implements SafeCloseable {
   private final IArray<Float> values;
   protected float topValue;
   protected float bottom;
@@ -64,7 +66,14 @@ public class FloatComparator extends NumericComparator<Float> {
     return new FloatLeafComparator(context);
   }
 
-  /** Leaf comparator for {@link FloatComparator} that provides skipping functionality */
+	@Override
+	public void close() {
+		if (values instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
+
+	/** Leaf comparator for {@link FloatComparator} that provides skipping functionality */
   public class FloatLeafComparator extends NumericLeafComparator {
 
     public FloatLeafComparator(LeafReaderContext context) throws IOException {

src/main/java/it/cavallium/dbengine/lucene/comparators/IntComparator.java

@@ -17,11 +17,13 @@
 
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.FloatCodec;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.IntCodec;
 import it.cavallium.dbengine.lucene.LMDBArray;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.document.IntPoint;
 import org.apache.lucene.index.LeafReaderContext;
@@ -32,7 +34,7 @@ import org.apache.lucene.search.LeafFieldComparator;
  * skipping functionality – an iterator that can skip over non-competitive documents.
  * Based on {@link org.apache.lucene.search.comparators.IntComparator}
  */
-public class IntComparator extends NumericComparator<Integer> {
+public class IntComparator extends NumericComparator<Integer> implements SafeCloseable {
   private final IArray<Integer> values;
   protected int topValue;
   protected int bottom;
@@ -64,7 +66,14 @@ public class IntComparator extends NumericComparator<Integer> {
     return new IntLeafComparator(context);
   }
 
-  /** Leaf comparator for {@link IntComparator} that provides skipping functionality */
+	@Override
+	public void close() {
+		if (values instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
+
+	/** Leaf comparator for {@link IntComparator} that provides skipping functionality */
   public class IntLeafComparator extends NumericLeafComparator {
 
     public IntLeafComparator(LeafReaderContext context) throws IOException {

src/main/java/it/cavallium/dbengine/lucene/comparators/LongComparator.java

@@ -17,11 +17,13 @@
 
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.IntCodec;
 import it.cavallium.dbengine.lucene.LMDBArray;
 import it.cavallium.dbengine.lucene.LongCodec;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.document.LongPoint;
 import org.apache.lucene.index.LeafReaderContext;
@@ -32,7 +34,7 @@ import org.apache.lucene.search.LeafFieldComparator;
  * functionality – an iterator that can skip over non-competitive documents.
  * Based on {@link org.apache.lucene.search.comparators.LongComparator}
  */
-public class LongComparator extends NumericComparator<Long> {
+public class LongComparator extends NumericComparator<Long> implements SafeCloseable {
   private final IArray<Long> values;
   protected long topValue;
   protected long bottom;
@@ -64,7 +66,14 @@ public class LongComparator extends NumericComparator<Long> {
     return new LongLeafComparator(context);
   }
 
-  /** Leaf comparator for {@link LongComparator} that provides skipping functionality */
+	@Override
+	public void close() {
+		if (values instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
+
+	/** Leaf comparator for {@link LongComparator} that provides skipping functionality */
   public class LongLeafComparator extends NumericLeafComparator {
 
     public LongLeafComparator(LeafReaderContext context) throws IOException {

src/main/java/it/cavallium/dbengine/lucene/comparators/RelevanceComparator.java

@@ -16,11 +16,13 @@
  */
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.FloatCodec;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.LMDBArray;
 import it.cavallium.dbengine.lucene.LongCodec;
+import java.io.Closeable;
 import java.io.IOException;
 import org.apache.lucene.index.BinaryDocValues;
 import org.apache.lucene.index.DocValues;
@@ -40,7 +42,7 @@ import org.apache.lucene.util.BytesRefBuilder;
  * org.apache.lucene.search.IndexSearcher#search(Query, int)} uses when no {@link org.apache.lucene.search.Sort} is specified).
  * Based on {@link org.apache.lucene.search.FieldComparator.RelevanceComparator}
  */
-public final class RelevanceComparator extends FieldComparator<Float> implements LeafFieldComparator {
+public final class RelevanceComparator extends FieldComparator<Float> implements LeafFieldComparator, SafeCloseable {
 
 	private final IArray<Float> scores;
 	private float bottom;
@@ -115,4 +117,11 @@ public final class RelevanceComparator extends FieldComparator<Float> implements
 		assert !Float.isNaN(docValue);
 		return Float.compare(docValue, topValue);
 	}
+
+	@Override
+	public void close() {
+		if (this.scores instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
 }

src/main/java/it/cavallium/dbengine/lucene/comparators/TermOrdValComparator.java

@@ -1,5 +1,6 @@
 package it.cavallium.dbengine.lucene.comparators;
 
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.ByteArrayCodec;
 import it.cavallium.dbengine.lucene.BytesRefCodec;
@@ -7,6 +8,7 @@ import it.cavallium.dbengine.lucene.FloatCodec;
 import it.cavallium.dbengine.lucene.IArray;
 import it.cavallium.dbengine.lucene.IntCodec;
 import it.cavallium.dbengine.lucene.LMDBArray;
+import java.io.Closeable;
 import java.io.IOException;
 import java.util.Arrays;
 import org.apache.lucene.index.DocValues;
@@ -28,7 +30,7 @@ import org.apache.lucene.util.BytesRefBuilder;
  * it may be slower.
  * Based on {@link org.apache.lucene.search.FieldComparator.TermOrdValComparator}
  */
-public class TermOrdValComparator extends FieldComparator<BytesRef> implements LeafFieldComparator {
+public class TermOrdValComparator extends FieldComparator<BytesRef> implements LeafFieldComparator, SafeCloseable {
 	/* Ords for each slot.
 	@lucene.internal */
 	final IArray<Integer> ords;
@@ -296,4 +298,17 @@ public class TermOrdValComparator extends FieldComparator<BytesRef> implements L
 
 	@Override
 	public void setScorer(Scorable scorer) {}
+
+	@Override
+	public void close() {
+		if (this.ords instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+		if (this.readerGen instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+		if (this.values instanceof SafeCloseable closeable) {
+			closeable.close();
+		}
+	}
 }

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

@@ -3,13 +3,17 @@ package it.cavallium.dbengine.lucene.searcher;
 import io.net5.buffer.api.Send;
 import it.cavallium.dbengine.database.LLKeyScore;
 import it.cavallium.dbengine.database.LLUtils;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLIndexSearchers;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.FullDocs;
 import it.cavallium.dbengine.lucene.LLFieldDoc;
 import it.cavallium.dbengine.lucene.LuceneUtils;
+import it.cavallium.dbengine.lucene.collector.FullDocsCollector;
 import it.cavallium.dbengine.lucene.collector.LMDBFullFieldDocCollector;
+import it.cavallium.dbengine.lucene.collector.LMDBFullScoreDocCollector;
 import it.cavallium.dbengine.lucene.searcher.LLSearchTransformer.TransformerInput;
+import java.util.List;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.IndexSearcher;
@@ -62,23 +66,55 @@ public class SortedScoredFullMultiSearcher implements MultiSearcher {
 					return LMDBFullFieldDocCollector.createSharedManager(env, queryParams.sort(), queryParams.limitInt(),
 							totalHitsThreshold);
 				})
-				.flatMap(sharedManager -> Flux
+				.<FullDocs<LLFieldDoc>>flatMap(sharedManager -> Flux
 						.fromIterable(indexSearchers)
 						.flatMap(shard -> Mono.fromCallable(() -> {
 							LLUtils.ensureBlocking();
 
 							var collector = sharedManager.newCollector();
-							assert queryParams.computePreciseHitsCount() == collector.scoreMode().isExhaustive();
+							try {
+								assert queryParams.computePreciseHitsCount() == collector.scoreMode().isExhaustive();
 
-							shard.search(queryParams.query(), collector);
-							return collector;
+								shard.search(queryParams.query(), collector);
+								return collector;
+							} catch (Throwable ex) {
+								collector.close();
+								throw ex;
+							}
 						}))
 						.collectList()
 						.flatMap(collectors -> Mono.fromCallable(() -> {
-							LLUtils.ensureBlocking();
-							return sharedManager.reduce(collectors);
+							try {
+								LLUtils.ensureBlocking();
+								return sharedManager.reduce(collectors);
+							} catch (Throwable ex) {
+								for (LMDBFullFieldDocCollector collector : collectors) {
+									collector.close();
+								}
+								throw ex;
+							}
 						}))
-				);
+				)
+
+				.doOnDiscard(List.class, list -> {
+					try {
+						for (Object o : list) {
+							if (o instanceof LMDBFullFieldDocCollector fullDocsCollector) {
+								fullDocsCollector.close();
+							}
+						}
+					} catch (Exception ex) {
+						logger.error("Failed to discard collector", ex);
+					}
+				})
+				.doOnDiscard(LMDBFullFieldDocCollector.class, fullDocsCollector -> {
+					try {
+						fullDocsCollector.close();
+					} catch (Exception ex) {
+						logger.error("Failed to discard collector", ex);
+					}
+				})
+				.doOnDiscard(FullDocs.class, SafeCloseable::close);
 	}
 
 	/**
@@ -96,7 +132,10 @@ public class SortedScoredFullMultiSearcher implements MultiSearcher {
 							indexSearchers.shards(), keyFieldName, true)
 					.take(queryParams.limitLong(), true);
 
-			return new LuceneSearchResult(totalHitsCount, hitsFlux, indexSearchers::close);
+			return new LuceneSearchResult(totalHitsCount, hitsFlux, () -> {
+				indexSearchers.close();
+				data.close();
+			});
 		});
 	}
 

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

@@ -3,13 +3,18 @@ package it.cavallium.dbengine.lucene.searcher;
 import io.net5.buffer.api.Send;
 import it.cavallium.dbengine.database.LLKeyScore;
 import it.cavallium.dbengine.database.LLUtils;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLIndexSearchers;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.LuceneUtils;
 import it.cavallium.dbengine.lucene.FullDocs;
 import it.cavallium.dbengine.lucene.LLScoreDoc;
+import it.cavallium.dbengine.lucene.collector.FullDocsCollector;
 import it.cavallium.dbengine.lucene.collector.LMDBFullScoreDocCollector;
 import it.cavallium.dbengine.lucene.searcher.LLSearchTransformer.TransformerInput;
+import java.io.Closeable;
+import java.io.IOException;
+import java.util.List;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.lucene.search.IndexSearcher;
@@ -74,17 +79,49 @@ public class UnsortedScoredFullMultiSearcher implements MultiSearcher {
 							LLUtils.ensureBlocking();
 
 							var collector = sharedManager.newCollector();
-							assert queryParams.computePreciseHitsCount() == collector.scoreMode().isExhaustive();
+							try {
+								assert queryParams.computePreciseHitsCount() == collector.scoreMode().isExhaustive();
 
-							shard.search(queryParams.query(), collector);
-							return collector;
+								shard.search(queryParams.query(), collector);
+								return collector;
+							} catch (Throwable ex) {
+								collector.close();
+								throw ex;
+							}
 						}))
 						.collectList()
 						.flatMap(collectors -> Mono.fromCallable(() -> {
-							LLUtils.ensureBlocking();
-							return sharedManager.reduce(collectors);
+							try {
+								LLUtils.ensureBlocking();
+								return sharedManager.reduce(collectors);
+							} catch (Throwable ex) {
+								for (LMDBFullScoreDocCollector collector : collectors) {
+									collector.close();
+								}
+								throw ex;
+							}
 						}))
-				);
+				)
+
+				.doOnDiscard(List.class, list -> {
+					try {
+						for (Object o : list) {
+							if (o instanceof FullDocsCollector<?,?,?> fullDocsCollector) {
+								fullDocsCollector.close();
+							}
+						}
+					} catch (Exception ex) {
+						logger.error("Failed to discard collector", ex);
+					}
+				})
+				.doOnDiscard(FullDocsCollector.class, fullDocsCollector -> {
+					try {
+						fullDocsCollector.close();
+					} catch (Exception ex) {
+						logger.error("Failed to discard collector", ex);
+					}
+				})
+				.doOnDiscard(FullDocs.class, SafeCloseable::close);
 	}
 
 	/**
@@ -102,7 +139,14 @@ public class UnsortedScoredFullMultiSearcher implements MultiSearcher {
 							indexSearchers.shards(), keyFieldName, true)
 					.take(queryParams.limitLong(), true);
 
-			return new LuceneSearchResult(totalHitsCount, hitsFlux, indexSearchers::close);
+			return new LuceneSearchResult(totalHitsCount, hitsFlux, () -> {
+				indexSearchers.close();
+				try {
+					data.close();
+				} catch (Exception e) {
+					logger.error("Failed to discard data", e);
+				}
+			});
 		});
 	}
 

src/test/java/it/cavallium/dbengine/PriorityQueueAdaptor.java

@@ -70,7 +70,7 @@ public class PriorityQueueAdaptor<T> implements PriorityQueue<T> {
 	}
 
 	@Override
-	public void close() throws IOException {
+	public void close() {
 		hitQueue.clear();
 		hitQueue.updateTop();
 	}

src/test/java/it/cavallium/dbengine/TestLMDB.java

@@ -1,5 +1,7 @@
 package it.cavallium.dbengine;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import io.net5.buffer.ByteBuf;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.LMDBSortedCodec;
@@ -142,6 +144,7 @@ public class TestLMDB {
 	@AfterEach
 	public void afterEach() throws IOException {
 		queue.close();
+		assertEquals(0, env.countUsedDbs());
 		env.close();
 	}
 }

src/test/java/it/cavallium/dbengine/TestLMDBHitQueue.java

@@ -1,7 +1,10 @@
 package it.cavallium.dbengine;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 import com.google.common.collect.Lists;
 import io.net5.buffer.ByteBuf;
+import it.cavallium.dbengine.database.SafeCloseable;
 import it.cavallium.dbengine.database.disk.LLTempLMDBEnv;
 import it.cavallium.dbengine.lucene.LLScoreDoc;
 import it.cavallium.dbengine.lucene.LMDBSortedCodec;
@@ -27,7 +30,7 @@ public class TestLMDBHitQueue {
 	public static final int NUM_HITS = 1024;
 
 	private LLTempLMDBEnv env;
-	private Closeable lmdbQueue;
+	private SafeCloseable lmdbQueue;
 
 	private TestingPriorityQueue testingPriorityQueue;
 
@@ -248,6 +251,7 @@ public class TestLMDBHitQueue {
 	@AfterEach
 	public void afterEach() throws IOException {
 		lmdbQueue.close();
+		assertEquals(0, env.countUsedDbs());
 		env.close();
 	}
 
@@ -346,8 +350,9 @@ public class TestLMDBHitQueue {
 		}
 
 		@Override
-		public void close() throws IOException {
-
+		public void close() {
+			referenceQueue.close();
+			testQueue.close();
 		}
 
 		private void ensureEquality() {

src/test/java/it/cavallium/dbengine/TestLuceneSearches.java

@@ -53,8 +53,10 @@ import java.util.stream.Stream;
 import org.apache.commons.lang3.function.FailableConsumer;
 import org.jetbrains.annotations.Nullable;
 import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
@@ -111,6 +113,7 @@ public class TestLuceneSearches {
 		luceneSingle = tempDb.luceneSingle();
 		luceneMulti = tempDb.luceneMulti();
 		ENV = new LLTempLMDBEnv();
+		assertEquals(0, ENV.countUsedDbs());
 
 		setUpIndex(true);
 		setUpIndex(false);
@@ -201,9 +204,20 @@ public class TestLuceneSearches {
 		}
 	}
 
+	@BeforeEach
+	public void beforeEach() {
+		assertEquals(0, ENV.countUsedDbs());
+	}
+
+	@AfterEach
+	public void afterEach() {
+		assertEquals(0, ENV.countUsedDbs());
+	}
+
 	@AfterAll
 	public static void afterAll() throws IOException {
 		TEMP_DB_GENERATOR.closeTempDb(tempDb).block();
+		assertEquals(0, ENV.countUsedDbs());
 		ENV.close();
 		ensureNoLeaks(allocator.allocator(), true, false);
 		destroyAllocator(allocator);