diff --git a/internal/core/unittest/test_regex_query.cpp b/internal/core/unittest/test_regex_query.cpp
index 9b03cb5376..455a582d7a 100644
--- a/internal/core/unittest/test_regex_query.cpp
+++ b/internal/core/unittest/test_regex_query.cpp
@@ -479,28 +479,33 @@ TEST_F(SealedSegmentRegexQueryTest, RegexQueryOnInvertedIndexStringField) {
     ASSERT_TRUE(final[4]);
 }
 
-// TODO: optimize this case
-// TEST_F(SealedSegmentRegexQueryTest, RegexQueryOnUnsupportedIndex) {
-//     std::string operand = "a%";
-//     const auto& str_meta = schema->operator[](FieldName("str"));
-//     auto column_info = test::GenColumnInfo(str_meta.get_id().get(),
-//                                            proto::schema::DataType::VarChar,
-//                                            false,
-//                                            false);
-//     auto unary_range_expr = test::GenUnaryRangeExpr(OpType::Match, operand);
-//     unary_range_expr->set_allocated_column_info(column_info);
-//     auto expr = test::GenExpr();
-//     expr->set_allocated_unary_range_expr(unary_range_expr);
+TEST_F(SealedSegmentRegexQueryTest, RegexQueryOnUnsupportedIndex) {
+    std::string operand = "a%";
+    const auto& str_meta = schema->operator[](FieldName("str"));
+    auto column_info = test::GenColumnInfo(str_meta.get_id().get(),
+                                           proto::schema::DataType::VarChar,
+                                           false,
+                                           false);
+    auto unary_range_expr = test::GenUnaryRangeExpr(OpType::Match, operand);
+    unary_range_expr->set_allocated_column_info(column_info);
+    auto expr = test::GenExpr();
+    expr->set_allocated_unary_range_expr(unary_range_expr);
 
-//     auto parser = ProtoParser(*schema);
-//     auto typed_expr = parser.ParseExprs(*expr);
-//     auto parsed =
-//         std::make_shared<plan::FilterBitsNode>(DEFAULT_PLANNODE_ID, typed_expr);
+    auto parser = ProtoParser(*schema);
+    auto typed_expr = parser.ParseExprs(*expr);
+    auto parsed =
+        std::make_shared<plan::FilterBitsNode>(DEFAULT_PLANNODE_ID, typed_expr);
 
-//     LoadMockIndex();
+    LoadMockIndex();
 
-//     auto segpromote = dynamic_cast<SegmentSealedImpl*>(seg.get());
-//     query::ExecPlanNodeVisitor visitor(*segpromote, MAX_TIMESTAMP);
-//     BitsetType final;
-//     ASSERT_ANY_THROW(visitor.ExecuteExprNode(parsed, segpromote, N, final));
-// }
+    auto segpromote = dynamic_cast<SegmentSealedImpl*>(seg.get());
+    query::ExecPlanNodeVisitor visitor(*segpromote, MAX_TIMESTAMP);
+    BitsetType final;
+    // regex query under this index will be executed using raw data (brute force).
+    visitor.ExecuteExprNode(parsed, segpromote, N, final);
+    ASSERT_FALSE(final[0]);
+    ASSERT_TRUE(final[1]);
+    ASSERT_TRUE(final[2]);
+    ASSERT_TRUE(final[3]);
+    ASSERT_TRUE(final[4]);
+}