[master] fix multi-stmt txn-free-route

src/observer/mysql/obmp_query.cpp

@@ -336,6 +336,9 @@ int ObMPQuery::process()
               if (i > 0) {
                 session.get_raw_audit_record().exec_timestamp_.multistmt_start_ts_
                                                               = ObTimeUtility::current_time();
+                // before handle multi-stmt's followers, re-calc the txn_free_route's baseline
+                // in order to capture accurate state changed by current stmt
+                session.prep_txn_free_route_baseline();
               }
               need_disconnect = true;
               //FIXME qianfu NG_TRACE_EXT(set_disconnect, OB_ID(disconnect), true, OB_ID(pos), "multi stmt begin");

src/sql/session/ob_sql_session_info.cpp

@@ -2437,16 +2437,26 @@ int ObSQLSessionInfo::on_user_disconnect()
   return ret;
 }
 
-void ObSQLSessionInfo::post_sync_session_info()
+// prepare baseline for the following `calc_txn_free_route` to get the diff
+void ObSQLSessionInfo::prep_txn_free_route_baseline(bool reset_audit)
 {
-  if (!get_is_in_retry()) {
 #define RESET_TXN_STATE_ENCODER_CHANGED_(x) txn_##x##_info_encoder_.is_changed_ = false
 #define RESET_TXN_STATE_ENCODER_CHANGED(x) RESET_TXN_STATE_ENCODER_CHANGED_(x)
   LST_DO(RESET_TXN_STATE_ENCODER_CHANGED, (;), static, dynamic, participants, extra);
 #undef RESET_TXN_STATE_ENCODER_CHANGED
 #undef RESET_TXN_STATE_ENCODER_CHANGED_
+  if (reset_audit) {
+    txn_free_route_ctx_.reset_audit_record();
+  }
   txn_free_route_ctx_.init_before_handle_request(tx_desc_);
 }
+
+void ObSQLSessionInfo::post_sync_session_info()
+{
+  if (!get_is_in_retry()) {
+    // preapre baseline for the following executing stmt/cmd
+    prep_txn_free_route_baseline(false);
+  }
 }
 
 void ObSQLSessionInfo::set_txn_free_route(bool txn_free_route)

src/sql/session/ob_sql_session_info.h

@@ -1186,6 +1186,7 @@ private:
   ObTxnExtraInfoEncoder txn_extra_info_encoder_;
 public:
   void post_sync_session_info();
+  void prep_txn_free_route_baseline(bool reset_audit = true);
   void set_txn_free_route(bool txn_free_route);
   int calc_txn_free_route();
   bool can_txn_free_route() const;