diff --git a/src/backend/commands/resgroupcmds.c b/src/backend/commands/resgroupcmds.c
index 384675edb7f..3b325ba729c 100644
--- a/src/backend/commands/resgroupcmds.c
+++ b/src/backend/commands/resgroupcmds.c
@@ -1632,17 +1632,21 @@ getCpuSetByRole(const char *cpuset)
 		splitcpuset = (char *)cpuset;
 	else
 	{
-		char *scpu = first + 1;
+		char *second = first + 1;
 
 		/* Get result cpuset by IS_QUERY_DISPATCHER(), on master or segment */
 		if (IS_QUERY_DISPATCHER())
-			splitcpuset = scpu;
-		else
 		{
 			char *mcpu = (char *)palloc0(sizeof(char) * MaxCpuSetLength);
 			strncpy(mcpu, cpuset, first - cpuset);
 			splitcpuset = mcpu;
 		}
+		else
+		{
+			char *scpu = (char *)palloc0(sizeof(char) * MaxCpuSetLength);
+			strlcpy(scpu, second, MaxCpuSetLength);
+			splitcpuset = scpu;
+		}
 	}
 
 	return splitcpuset;
diff --git a/src/backend/commands/test/Makefile b/src/backend/commands/test/Makefile
index 83bd803a23a..5ef9fed8894 100644
--- a/src/backend/commands/test/Makefile
+++ b/src/backend/commands/test/Makefile
@@ -2,7 +2,7 @@ subdir=src/backend/commands
 top_builddir=../../../..
 include $(top_builddir)/src/Makefile.global
 
-TARGETS=tablecmds
+TARGETS=tablecmds resgroupcmds
 
 include $(top_srcdir)/src/backend/mock.mk
 
@@ -10,3 +10,6 @@ tablecmds.t: \
 	$(MOCK_DIR)/backend/access/aocs/aocs_compaction_mock.o \
 	$(MOCK_DIR)/backend/access/hash/hash_mock.o \
 	$(MOCK_DIR)/backend/utils/fmgr/fmgr_mock.o
+
+resgroupcmds.t: \
+	$(MOCK_DIR)/backend/utils/fmgr/fmgr_mock.o
diff --git a/src/backend/commands/test/resgroupcmds_test.c b/src/backend/commands/test/resgroupcmds_test.c
new file mode 100644
index 00000000000..2e7250104e4
--- /dev/null
+++ b/src/backend/commands/test/resgroupcmds_test.c
@@ -0,0 +1,135 @@
+/*-------------------------------------------------------------------------
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ *
+ * resgroupcmds_test.c
+ *
+ * IDENTIFICATION
+ *	  src/backend/commands/test/resgroupcmds_test.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include "cmockery.h"
+
+#include "../resgroupcmds.c"
+
+/*
+ * Helper: simulate running on the coordinator (dispatcher).
+ */
+static void
+set_role_coordinator(void)
+{
+	GpIdentity.segindex = MASTER_CONTENT_ID;
+}
+
+/*
+ * Helper: simulate running on a segment.
+ */
+static void
+set_role_segment(void)
+{
+	GpIdentity.segindex = 0;
+}
+
+/*
+ * NULL input must raise an ERROR.
+ */
+static void
+test__getCpuSetByRole_null_input(void **state)
+{
+	PG_TRY();
+	{
+		getCpuSetByRole(NULL);
+		fail_msg("expected ereport(ERROR) for NULL cpuset");
+	}
+	PG_CATCH();
+	{
+		FlushErrorState();
+	}
+	PG_END_TRY();
+}
+
+/*
+ * cpuset without a separator: same value must be returned
+ * regardless of the role.
+ */
+static void
+test__getCpuSetByRole_no_separator(void **state)
+{
+	const char *input = "0-7";
+	char *result;
+
+	set_role_coordinator();
+	result = getCpuSetByRole(input);
+	assert_string_equal(result, "0-7");
+
+	set_role_segment();
+	result = getCpuSetByRole(input);
+	assert_string_equal(result, "0-7");
+}
+
+/*
+ * cpuset with a separator, called as coordinator:
+ * must return the part BEFORE the ';'.
+ */
+static void
+test__getCpuSetByRole_with_separator_as_coordinator(void **state)
+{
+	const char *input = "0-7;0-15";
+	char *result;
+
+	set_role_coordinator();
+	result = getCpuSetByRole(input);
+	assert_string_equal(result, "0-7");
+}
+
+/*
+ * cpuset with a separator, called as segment:
+ * must return the part AFTER the ';'.
+ */
+static void
+test__getCpuSetByRole_with_separator_as_segment(void **state)
+{
+	const char *input = "0-7;0-15";
+	char *result;
+
+	set_role_segment();
+	result = getCpuSetByRole(input);
+	assert_string_equal(result, "0-15");
+}
+
+int
+main(int argc, char *argv[])
+{
+	cmockery_parse_arguments(argc, argv);
+
+	const UnitTest tests[] = {
+		unit_test(test__getCpuSetByRole_null_input),
+		unit_test(test__getCpuSetByRole_no_separator),
+		unit_test(test__getCpuSetByRole_with_separator_as_coordinator),
+		unit_test(test__getCpuSetByRole_with_separator_as_segment)
+	};
+
+	MemoryContextInit();
+
+	return run_tests(tests);
+}