diff --git a/src/pl/ob_pl_user_type.cpp b/src/pl/ob_pl_user_type.cpp
index 4d1c8e197..6b7459482 100644
--- a/src/pl/ob_pl_user_type.cpp
+++ b/src/pl/ob_pl_user_type.cpp
@@ -4500,6 +4500,15 @@ int64_t ObPLAssocArray::get_last()
   return last_;
 }
 
+ObIAllocator& ObPLOpaque::get_allocator()
+{
+  int ret = OB_SUCCESS;
+  if (allocator_.used() > 1024 * 1024 * 512) {
+    LOG_ERROR("opaque allocator hold too much memory", K(allocator_.used()));
+  }
+  return allocator_;
+}
+
 int ObPLOpaque::deep_copy(ObPLOpaque *dst)
 {
   int ret = OB_SUCCESS;
diff --git a/src/pl/ob_pl_user_type.h b/src/pl/ob_pl_user_type.h
index f67985855..7ee6b87a9 100644
--- a/src/pl/ob_pl_user_type.h
+++ b/src/pl/ob_pl_user_type.h
@@ -1206,7 +1206,7 @@ public:
   inline bool is_xmltype() const { return ObPLOpaqueType::PL_XML_TYPE == type_; }
   inline bool is_json_type() const { return ObPLOpaqueType::PL_JSON_TYPE == type_; }
 
-  inline ObIAllocator& get_allocator() { return allocator_; }
+  ObIAllocator& get_allocator(); // { return allocator_; }
 
   virtual int deep_copy(ObPLOpaque *dst);