diff --git a/src/server/redis_connection.cc b/src/server/redis_connection.cc
index dddfe53cdff..d6100bc3454 100644
--- a/src/server/redis_connection.cc
+++ b/src/server/redis_connection.cc
@@ -173,6 +173,8 @@ std::string Connection::SetOfBulkStrings(const std::vector<std::string> &elems)
 }
 
 std::string Connection::MapOfBulkStrings(const std::vector<std::string> &elems) const {
+  DCHECK(elems.size() % 2 == 0);
+
   std::string result;
   result += SizeOfMap(elems.size() / 2);
   for (const auto &elem : elems) {