diff --git a/dbms/src/Common/MemoryTracker.cpp b/dbms/src/Common/MemoryTracker.cpp
index a70a8017cac..e4218edfe74 100644
--- a/dbms/src/Common/MemoryTracker.cpp
+++ b/dbms/src/Common/MemoryTracker.cpp
@@ -77,8 +77,8 @@ void MemoryTracker::alloc(Int64 size, bool check_memory_limit)
     if (check_memory_limit)
     {
         Int64 current_limit = limit.load(std::memory_order_relaxed);
-
-        if (unlikely(!next.load(std::memory_order_relaxed) && accuracy_diff_for_test && current_limit && real_rss > accuracy_diff_for_test + current_limit))
+        Int64 current_accuracy_diff_for_test = accuracy_diff_for_test.load(std::memory_order_relaxed);
+        if (unlikely(!next.load(std::memory_order_relaxed) && current_accuracy_diff_for_test && current_limit && real_rss > current_accuracy_diff_for_test + current_limit))
         {
             DB::FmtBuffer fmt_buf;
             fmt_buf.append("Memory tracker accuracy ");
@@ -108,9 +108,10 @@ void MemoryTracker::alloc(Int64 size, bool check_memory_limit)
 
             throw DB::TiFlashException(fmt_buf.toString(), DB::Errors::Coprocessor::MemoryLimitExceeded);
         }
+        Int64 current_bytes_rss_larger_than_limit = bytes_rss_larger_than_limit.load(std::memory_order_relaxed);
         bool is_rss_too_large = (!next.load(std::memory_order_relaxed) && current_limit
-                                 && real_rss > current_limit + bytes_rss_larger_than_limit
-                                 && will_be > current_limit - (real_rss - current_limit - bytes_rss_larger_than_limit));
+                                 && real_rss > current_limit + current_bytes_rss_larger_than_limit
+                                 && will_be > current_limit - (real_rss - current_limit - current_bytes_rss_larger_than_limit));
         if (is_rss_too_large
             || unlikely(current_limit && will_be > current_limit))
         {
diff --git a/dbms/src/Common/MemoryTracker.h b/dbms/src/Common/MemoryTracker.h
index 453b5c4814d..5248303adec 100644
--- a/dbms/src/Common/MemoryTracker.h
+++ b/dbms/src/Common/MemoryTracker.h
@@ -39,13 +39,13 @@ class MemoryTracker : public std::enable_shared_from_this<MemoryTracker>
     std::atomic<Int64> limit{0};
 
     // How many bytes RSS(Resident Set Size) can be larger than limit(max_memory_usage_for_all_queries). Default: 5GB
-    Int64 bytes_rss_larger_than_limit = 5368709120;
+    std::atomic<Int64> bytes_rss_larger_than_limit{1073741824};
 
     /// To test exception safety of calling code, memory tracker throws an exception on each memory allocation with specified probability.
     double fault_probability = 0;
 
     /// To test the accuracy of memory track, it throws an exception when the part exceeding the tracked amount is greater than accuracy_diff_for_test.
-    Int64 accuracy_diff_for_test = 0;
+    std::atomic<Int64> accuracy_diff_for_test{0};
 
     /// Singly-linked list. All information will be passed to subsequent memory trackers also (it allows to implement trackers hierarchy).
     /// In terms of tree nodes it is the list of parents. Lifetime of these trackers should "include" lifetime of current tracker.
@@ -103,11 +103,11 @@ class MemoryTracker : public std::enable_shared_from_this<MemoryTracker>
       */
     void setOrRaiseLimit(Int64 value);
 
-    void setBytesThatRssLargerThanLimit(Int64 value) { bytes_rss_larger_than_limit = value; }
+    void setBytesThatRssLargerThanLimit(Int64 value) { bytes_rss_larger_than_limit.store(value, std::memory_order_relaxed); }
 
     void setFaultProbability(double value) { fault_probability = value; }
 
-    void setAccuracyDiffForTest(double value) { accuracy_diff_for_test = value; }
+    void setAccuracyDiffForTest(Int64 value) { accuracy_diff_for_test.store(value, std::memory_order_relaxed); }
 
     /// next should be changed only once: from nullptr to some value.
     void setNext(MemoryTracker * elem)
diff --git a/dbms/src/Flash/Mpp/MPPTunnel.cpp b/dbms/src/Flash/Mpp/MPPTunnel.cpp
index fca29852a16..2d872d2e58b 100644
--- a/dbms/src/Flash/Mpp/MPPTunnel.cpp
+++ b/dbms/src/Flash/Mpp/MPPTunnel.cpp
@@ -113,8 +113,7 @@ void MPPTunnel::finishSendQueue(bool drain)
 void MPPTunnel::close(const String & reason)
 {
     SCOPE_EXIT({
-        // ensure the tracked memory is released and updated before memory tracker(in ProcListEntry) is released
-        finishSendQueue(true); // drain the send_queue when close
+        finishSendQueue(true); // drain the send_queue when close, to release useless memory
     });
     {
         std::unique_lock lk(mu);