diff --git a/src/main/java/it/cavallium/dbengine/database/LLUtils.java b/src/main/java/it/cavallium/dbengine/database/LLUtils.java
index c87e86f..5f21710 100644
--- a/src/main/java/it/cavallium/dbengine/database/LLUtils.java
+++ b/src/main/java/it/cavallium/dbengine/database/LLUtils.java
@@ -809,8 +809,8 @@ public class LLUtils {
 	public static <U> Mono<Delta<U>> mapLLDelta(Mono<LLDelta> mono,
 			SerializationFunction<@NotNull Buffer, @Nullable U> mapper) {
 		return Mono.usingWhen(mono, delta -> Mono.fromCallable(() -> {
-			Buffer prev = delta.previousUnsafe();
-			Buffer curr = delta.currentUnsafe();
+			try (Buffer prev = delta.previousUnsafe();
+			Buffer curr = delta.currentUnsafe()) {
 			U newPrev;
 			U newCurr;
 			if (prev != null) {
@@ -824,6 +824,7 @@ public class LLUtils {
 				newCurr = null;
 			}
 			return new Delta<>(newPrev, newCurr);
+			}
 		}), delta -> Mono.fromRunnable(delta::close));
 	}
 
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 ab645d6..e2725e4 100644
--- a/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java
+++ b/src/main/java/it/cavallium/dbengine/database/collections/DatabaseMapDictionary.java
@@ -281,10 +281,10 @@ public class DatabaseMapDictionary<T, U> extends DatabaseMapDictionaryDeep<T, U,
 	public Mono<Void> putValue(T keySuffix, U value) {
 		var keyMono = Mono.fromCallable(() -> serializeKeySuffixToKey(keySuffix)).single();
 		var valueMono = Mono.fromCallable(() -> serializeValue(value)).single();
-		return dictionary
-				.put(keyMono, valueMono, LLDictionaryResultType.VOID)
-				.doOnNext(Resource::close)
-				.then();
+		return Mono.usingWhen(dictionary.put(keyMono, valueMono, LLDictionaryResultType.VOID),
+				v -> Mono.empty(),
+				v -> Mono.fromRunnable(v::close)
+		);
 	}
 
 	@Override
@@ -316,7 +316,9 @@ public class DatabaseMapDictionary<T, U> extends DatabaseMapDictionaryDeep<T, U,
 			if (oldSerialized == null) {
 				result = updater.apply(null);
 			} else {
-				result = updater.apply(valueSerializer.deserialize(oldSerialized));
+				try (oldSerialized) {
+					result = updater.apply(valueSerializer.deserialize(oldSerialized));
+				}
 			}
 			if (result == null) {
 				return null;