diff --git a/dbms/src/Flash/tests/gtest_compute_server.cpp b/dbms/src/Flash/tests/gtest_compute_server.cpp
index 0879bbef7fc..24c5496ab50 100644
--- a/dbms/src/Flash/tests/gtest_compute_server.cpp
+++ b/dbms/src/Flash/tests/gtest_compute_server.cpp
@@ -985,7 +985,7 @@ try
             addOneQuery(i + 10, running_queries, gather_ids);
         }
         using namespace std::literals::chrono_literals;
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         ASSERT_TRUE(
             TiFlashMetrics::instance()
                 .tiflash_task_scheduler.get(tiflash_task_scheduler_metrics::type_active_queries_count, "")
@@ -997,7 +997,7 @@ try
                 .Value()
             == 0);
         addOneQuery(1, running_queries, gather_ids);
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         ASSERT_TRUE(
             TiFlashMetrics::instance()
                 .tiflash_task_scheduler.get(tiflash_task_scheduler_metrics::type_active_queries_count, "")
@@ -1020,7 +1020,7 @@ try
             addOneQuery((i + 1) * 20, running_queries, gather_ids);
         }
         using namespace std::literals::chrono_literals;
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         ASSERT_TRUE(
             TiFlashMetrics::instance()
                 .tiflash_task_scheduler.get(tiflash_task_scheduler_metrics::type_active_queries_count, "")
@@ -1032,7 +1032,7 @@ try
                 .Value()
             == 0);
         addOneQuery(30, running_queries, gather_ids);
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         ASSERT_TRUE(
             TiFlashMetrics::instance()
                 .tiflash_task_scheduler.get(tiflash_task_scheduler_metrics::type_active_queries_count, "")
@@ -1046,7 +1046,7 @@ try
         /// cancel 1 running query
         MockComputeServerManager::instance().cancelGather(gather_ids[0]);
         running_queries[0].join();
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         ASSERT_TRUE(
             TiFlashMetrics::instance()
                 .tiflash_task_scheduler.get(tiflash_task_scheduler_metrics::type_active_queries_count, "")
@@ -1103,7 +1103,7 @@ try
         single_gather_properties.gather_id = 1;
         addOneGather(running_queries, gather_ids, single_gather_properties);
         using namespace std::literals::chrono_literals;
-        std::this_thread::sleep_for(2s);
+        std::this_thread::sleep_for(4s);
         /// 6 gathers, but two query
         ASSERT_TRUE(
             TiFlashMetrics::instance()
diff --git a/dbms/src/TestUtils/MPPTaskTestUtils.cpp b/dbms/src/TestUtils/MPPTaskTestUtils.cpp
index c2240c1abdf..adf51f5f5d7 100644
--- a/dbms/src/TestUtils/MPPTaskTestUtils.cpp
+++ b/dbms/src/TestUtils/MPPTaskTestUtils.cpp
@@ -108,6 +108,7 @@ BlockInputStreamPtr MPPTaskTestUtils::prepareMPPStreams(DAGRequestBuilder builde
 
 std::vector<QueryTask> MPPTaskTestUtils::prepareMPPTasks(DAGRequestBuilder builder, const DAGProperties & properties)
 {
+    std::lock_guard lock(mu);
     auto tasks = builder.buildMPPTasks(context, properties);
     for (int i = test_meta.context_idx; i < TiFlashTestEnv::globalContextSize(); ++i)
         TiFlashTestEnv::getGlobalContext(i).setCancelTest();
diff --git a/dbms/src/TestUtils/MPPTaskTestUtils.h b/dbms/src/TestUtils/MPPTaskTestUtils.h
index 7f5ae002ec3..3023cf24b85 100644
--- a/dbms/src/TestUtils/MPPTaskTestUtils.h
+++ b/dbms/src/TestUtils/MPPTaskTestUtils.h
@@ -104,6 +104,7 @@ class MPPTaskTestUtils : public ExecutorTest
     static LoggerPtr log_ptr;
     static size_t server_num;
     static MPPTestMeta test_meta;
+    std::mutex mu;
 };
 
 #define ASSERT_MPPTASK_EQUAL(tasks, properties, expected_cols)                      \