diff --git a/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java b/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java
index e2725e4..13282ae 100644
--- a/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java
+++ b/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java
@@ -484,10 +484,11 @@ public class DatabaseMapDictionary<T, U> extends DatabaseMapDictionaryDeep<T, U,
 		if (keyMin == null && keyMax == null) {
 			return getAllStages(snapshot, smallRange);
 		} else {
-			Mono<LLRange> boundedRangeMono = Mono.usingWhen(rangeMono,
-					range -> Mono.fromCallable(() -> getPatchedRange(range, keyMin, keyMax)),
-					range -> Mono.fromRunnable(range::close)
-			);
+			Mono<LLRange> boundedRangeMono = rangeMono.map(range -> {
+				try (range) {
+					return getPatchedRange(range, keyMin, keyMax);
+				}
+			});
 			return getAllStages(snapshot, boundedRangeMono, reverse, smallRange);
 		}
 	}
diff --git a/src/main/java/it/cavallium/dbengine/database/disk/OptimisticRocksDBColumn.java b/src/main/java/it/cavallium/dbengine/database/disk/OptimisticRocksDBColumn.java
index 9b749c7..df94139 100644
--- a/src/main/java/it/cavallium/dbengine/database/disk/OptimisticRocksDBColumn.java
+++ b/src/main/java/it/cavallium/dbengine/database/disk/OptimisticRocksDBColumn.java
@@ -128,6 +128,7 @@ public final class OptimisticRocksDBColumn extends AbstractRocksDBColumn<Optimis
 							prevDataToSendToUpdater = null;
 						}
 						try {
+							assert newData == null || !newData.isAccessible();
 							newData = updater.apply(prevDataToSendToUpdater);
 						} finally {
 							if (prevDataToSendToUpdater != null && prevDataToSendToUpdater.isAccessible()) {