Fixed cache bug

src/main/java/it/cavallium/strangedb/database/references/DatabaseReferencesMetadataCache.java

@@ -81,13 +81,14 @@ public class DatabaseReferencesMetadataCache {
 		if (closed) throw new IOException("Cache already closed!");
 		lock.writeLock().lock();
 		try {
+			Long2LongMap referencesBlocksToAdd = new Long2LongLinkedOpenHashMap(references, blockIds, 0.5f);
+			Long2ByteMap referencesCleanersToAdd = new Long2ByteLinkedOpenHashMap(references, cleanerIds, 0.5f);
 			for (int i = 0; i < references.length; i++) {
 				if (cleanerIds[i] == 0) {
-					throw new IOException("Null cleaner id");
+					referencesBlocksToAdd.remove(references[i]);
+					referencesCleanersToAdd.remove(references[i]);
 				}
 			}
-			Long2LongMap referencesBlocksToAdd = new Long2LongLinkedOpenHashMap(references, blockIds, 0.5f);
-			Long2ByteMap referencesCleanersToAdd = new Long2ByteLinkedOpenHashMap(references, cleanerIds, 0.5f);
 			references2Blocks.putAll(referencesBlocksToAdd);
 			referencesCleaners.putAll(referencesCleanersToAdd);
 			flush();