SQL: Backup_query_start_time RAII

sql/sp_head.cc

@@ -3273,7 +3273,7 @@ sp_instr_stmt::execute(THD *thd, uint *nextp)
   int res;
   bool save_enable_slow_log;
   const CSET_STRING query_backup= thd->query_string;
-  QUERY_START_TIME_INFO time_info;
+  Backup_query_start_time time_info;
   Sub_statement_state backup_state;
   DBUG_ENTER("sp_instr_stmt::execute");
   DBUG_PRINT("info", ("command: %d", m_lex_keeper.sql_command()));
@@ -3289,7 +3289,7 @@ sp_instr_stmt::execute(THD *thd, uint *nextp)
       Save start time info for the CALL statement and overwrite it with the
       current time for log_slow_statement() to log the individual query timing.
     */
-    thd->backup_query_start_time(&time_info);
+    time_info.backup(*thd);
     thd->set_time();
   }
   thd->store_slow_query_state(&backup_state);
@@ -3355,9 +3355,6 @@ sp_instr_stmt::execute(THD *thd, uint *nextp)
       thd->get_stmt_da()->reset_diagnostics_area();
     }
   }
-  /* Restore the original query start time */
-  if (thd->enable_slow_log)
-    thd->restore_query_start_time(&time_info);
 
   DBUG_RETURN(res || thd->is_error());
 }

sql/sql_class.h

@@ -2085,14 +2085,36 @@ struct QUERY_START_TIME_INFO
   my_time_t start_time;
   ulong     start_time_sec_part;
   ulonglong start_utime, utime_after_lock;
+};
+
+class Backup_query_start_time : public QUERY_START_TIME_INFO
+{
+  QUERY_START_TIME_INFO *m_origin;
 
-  void backup_query_start_time(QUERY_START_TIME_INFO *backup)
+public:
+  Backup_query_start_time() : m_origin(NULL)
+  {}
+  Backup_query_start_time(QUERY_START_TIME_INFO &origin)
   {
-    *backup= *this;
+    backup(origin);
   }
-  void restore_query_start_time(QUERY_START_TIME_INFO *backup)
+  ~Backup_query_start_time()
   {
-    *this= *backup;
+    restore();
+  }
+  void backup(QUERY_START_TIME_INFO &origin)
+  {
+    m_origin= &origin;
+    QUERY_START_TIME_INFO *backup_= this;
+    *backup_= origin;
+  }
+  void restore()
+  {
+    if (m_origin)
+    {
+      *m_origin= *this;
+      m_origin= NULL;
+    }
   }
 };