diff --git a/Makefile b/Makefile
index 44ae69404..7693d8205 100644
--- a/Makefile
+++ b/Makefile
@@ -504,6 +504,7 @@ PARALLEL_TEST = \
 	backupable_db_test \
 	db_compaction_filter_test \
 	db_compaction_test \
+	db_merge_operator_test \
 	db_sst_test \
 	db_test \
 	db_universal_compaction_test \
@@ -515,7 +516,7 @@ PARALLEL_TEST = \
 	persistent_cache_test \
 	table_test \
 	transaction_test \
-	write_prepared_transaction_test
+	write_prepared_transaction_test \
 
 SUBSET := $(TESTS)
 ifdef ROCKSDBTESTS_START
diff --git a/TARGETS b/TARGETS
index 6e7954d1e..2846bb826 100644
--- a/TARGETS
+++ b/TARGETS
@@ -567,7 +567,7 @@ ROCKS_TESTS = [
     [
         "db_merge_operator_test",
         "db/db_merge_operator_test.cc",
-        "serial",
+        "parallel",
     ],
     [
         "db_options_test",
@@ -1017,7 +1017,7 @@ ROCKS_TESTS = [
     [
         "write_prepared_transaction_test",
         "utilities/transactions/write_prepared_transaction_test.cc",
-        "serial",
+        "parallel",
     ],
 ]