diff --git a/src/pl/ob_pl.cpp b/src/pl/ob_pl.cpp
index 2bcf6eb77e..e3920a6bc2 100644
--- a/src/pl/ob_pl.cpp
+++ b/src/pl/ob_pl.cpp
@@ -2327,6 +2327,19 @@ int ObPLExecState::set_var(int64_t var_idx, const ObObjParam& value)
   }
 
   if (OB_FAIL(ret)) {
+  } else if (copy_value.is_null() && params->at(var_idx).is_pl_extend()) {
+    if (params->at(var_idx).get_ext() == 0) {
+      const ObUserDefinedType *user_type = NULL;
+      uint64_t udt_id = params->at(var_idx).get_udt_id();
+      OZ (ctx_.get_user_type(udt_id, user_type), K(udt_id));
+      CK (OB_NOT_NULL(user_type));
+      OZ (init_complex_obj(*get_allocator(), *user_type, params->at(var_idx)));
+      if (OB_SUCC(ret) && user_type->is_collection_type()) {
+        ObPLCollection *coll = reinterpret_cast<ObPLCollection *>(params->at(var_idx).get_ext());
+        CK (OB_NOT_NULL(coll));
+        OX (coll->set_count(OB_INVALID_COUNT));
+      }
+    }
   } else if (!copy_value.is_ext()) {
     bool is_ref_cursor = params->at(var_idx).is_ref_cursor_type();
     copy_value.ObObj::set_scale(params->at(var_idx).get_meta().get_scale());
diff --git a/src/pl/ob_pl_package.cpp b/src/pl/ob_pl_package.cpp
index 0f0420e920..b0f5806d17 100644
--- a/src/pl/ob_pl_package.cpp
+++ b/src/pl/ob_pl_package.cpp
@@ -196,14 +196,12 @@ int ObPLPackage::instantiate_package_state(const ObPLResolveCtx &resolve_ctx,
       if (var_type.is_cursor_type()
           && OB_FAIL(resolve_ctx.session_info_.init_cursor_cache())) {
         LOG_WARN("failed to init cursor cache", K(ret));
-      } else if (var->is_formal_param()) {
-        // cursor formal param will as variable added to symbol, skip cursor formal param init
       } else if (OB_FAIL(var_type.init_session_var(resolve_ctx,
                                             var_type.is_cursor_type() ?
                                               package_state.get_pkg_cursor_allocator()
                                               : package_state.get_pkg_allocator(),
                                             exec_ctx,
-                                            get_default_expr(var->get_default()),
+                                            var->is_formal_param() ? NULL : get_default_expr(var->get_default()),
                                             var->is_default_construct(),
                                             value))) {
         LOG_WARN("init sesssion var failed", K(ret));
diff --git a/src/pl/ob_pl_package_state.cpp b/src/pl/ob_pl_package_state.cpp
index af5504a0b3..39f223c514 100644
--- a/src/pl/ob_pl_package_state.cpp
+++ b/src/pl/ob_pl_package_state.cpp
@@ -206,6 +206,12 @@ int ObPLPackageState::set_package_var_val(const int64_t var_idx, const ObObj &va
       ObObj copy;
       OZ (ObUserDefinedType::deep_copy_obj(inner_allocator_, value, copy));
       OX (vars_.at(var_idx) = copy);
+    } else if (value.is_null()
+               && vars_.at(var_idx).is_pl_extend()
+               && types_.at(var_idx) != PL_CURSOR_TYPE
+               && types_.at(var_idx) != PL_REF_CURSOR_TYPE) {
+      CK (vars_.at(var_idx).get_ext() != 0);
+      OZ (ObUserDefinedType::destruct_obj(vars_.at(var_idx)));
     } else {
       vars_.at(var_idx) = value;
     }
diff --git a/src/pl/ob_pl_user_type.cpp b/src/pl/ob_pl_user_type.cpp
index 92bb927e43..8e9917058d 100644
--- a/src/pl/ob_pl_user_type.cpp
+++ b/src/pl/ob_pl_user_type.cpp
@@ -330,7 +330,7 @@ int ObUserDefinedType::destruct_obj(ObObj &src, ObSQLSessionInfo *session)
       for (int64_t i = 0; OB_SUCC(ret) && i < record->get_count(); ++i) {
         OZ (destruct_obj(record->get_element()[i], session));
       }
-      OX (src.set_null());
+      OX (record->set_null());
     }
       break;
     default: {