diff --git a/lib/redis/rediswriter-utility.cpp b/lib/redis/rediswriter-utility.cpp
index 4c6b378ad..0fecd8c22 100644
--- a/lib/redis/rediswriter-utility.cpp
+++ b/lib/redis/rediswriter-utility.cpp
@@ -45,10 +45,15 @@ String RedisWriter::CalculateCheckSumGroups(const Array::Ptr& groups)
 {
 	String output;
 
-	{
-		ObjectLock olock(groups);
+	/* Ensure that checksums happen in a defined order. */
+	Array::Ptr tmpGroups = groups->ShallowClone();
 
-		for (const String& group : groups) {
+	tmpGroups->Sort();
+
+	{
+		ObjectLock olock(tmpGroups);
+
+		for (const String& group : tmpGroups) {
 			output += SHA1(group);
 		}
 	}