diff --git a/src/bvar/multi_dimension.h b/src/bvar/multi_dimension.h
index 27f3e5144f..43be82ccfd 100644
--- a/src/bvar/multi_dimension.h
+++ b/src/bvar/multi_dimension.h
@@ -134,10 +134,15 @@ class MultiDimension : public MVariable {
     
     // Remove all stats so those not count and dump
     void delete_stats();
+
+    void set_max_stats_count(size_t max_stats_count) {
+        _max_stats_count = max_stats_count;
+    }
     
     static size_t init_flatmap(MetricMap& bg);
     
 private:
+    size_t _max_stats_count;
     MetricMapDBD _metric_map;
 };
 
diff --git a/src/bvar/multi_dimension_inl.h b/src/bvar/multi_dimension_inl.h
index 212f431b96..a0158b15db 100644
--- a/src/bvar/multi_dimension_inl.h
+++ b/src/bvar/multi_dimension_inl.h
@@ -37,6 +37,7 @@ template <typename T>
 inline
 MultiDimension<T>::MultiDimension(const key_type& labels)
     : Base(labels)
+    , _max_stats_count(MAX_MULTI_DIMENSION_STATS_COUNT)
 {
     _metric_map.Modify(init_flatmap);
 }
@@ -45,9 +46,8 @@ template <typename T>
 inline
 MultiDimension<T>::MultiDimension(const butil::StringPiece& name,
                                   const key_type& labels)
-    : Base(labels)
+    : MultiDimension(labels)
 {
-    _metric_map.Modify(init_flatmap);
     this->expose(name);
 }
 
@@ -56,9 +56,8 @@ inline
 MultiDimension<T>::MultiDimension(const butil::StringPiece& prefix,
                                   const butil::StringPiece& name,
                                   const key_type& labels)
-    : Base(labels)
+    : MultiDimension(labels)
 {
-    _metric_map.Modify(init_flatmap);
     this->expose_as(prefix, name);
 }
 
@@ -190,8 +189,8 @@ T* MultiDimension<T>::get_stats_impl(const key_type& labels_value, STATS_OP stat
             return nullptr;
         }
 
-        if (metric_map_ptr->size() > MAX_MULTI_DIMENSION_STATS_COUNT) {
-            LOG(ERROR) << "Too many stats seen, overflow detected, max stats count:" << MAX_MULTI_DIMENSION_STATS_COUNT;
+        if (metric_map_ptr->size() > _max_stats_count) {
+            LOG(ERROR) << "Too many stats seen, overflow detected, max stats count=" << _max_stats_count;
             return nullptr;
         }
     }
diff --git a/test/Makefile b/test/Makefile
index cb0465446c..f09b398dfc 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -159,6 +159,8 @@ ifeq ($(SYSTEM), Darwin)
 	DYNAMIC_LINKINGS+=-Wl,-U,_bthread_getspecific
 	DYNAMIC_LINKINGS+=-Wl,-U,_bthread_setspecific
 	DYNAMIC_LINKINGS+=-Wl,-U,_bthread_key_create
+	DYNAMIC_LINKINGS+=-Wl,-U,_bthread_self
+	DYNAMIC_LINKINGS+=-Wl,-U,_bthread_timed_connect
 endif
 
 UT_DYNAMIC_LINKINGS = -lbrpc.dbg $(DYNAMIC_LINKINGS)