cleanup: remove thd->stmt_changes_data

what is done in the plugin - stays in the plugin

plugin/query_response_time/plugin.cc

@@ -231,7 +231,9 @@ static void query_response_time_audit_notify(MYSQL_THD thd,
   if (event_general->event_subclass == MYSQL_AUDIT_GENERAL_STATUS &&
       query_response_time_should_log(thd))
   {
-    QUERY_TYPE query_type= (thd->stmt_changes_data ? WRITE : READ);
+    bool stmt_changes_data= is_update_query(thd->last_sql_command)
+                         || thd->transaction->stmt.is_trx_read_write();
+    QUERY_TYPE query_type= stmt_changes_data ? WRITE : READ;
 #ifndef DBUG_OFF
     if (THDVAR(thd, exec_time_debug))
     {

sql/handler.cc

@@ -5288,7 +5288,6 @@ void handler::mark_trx_read_write_internal()
     if (table_share == NULL || table_share->tmp_table == NO_TMP_TABLE)
       ha_info->set_trx_read_write();
   }
-  thd->stmt_changes_data= 1;
 }
 
 

sql/sql_class.cc

@@ -661,7 +661,7 @@ THD::THD(my_thread_id id, bool is_wsrep_applier)
    bootstrap(0),
    derived_tables_processing(FALSE),
    waiting_on_group_commit(FALSE), has_waiter(FALSE),
-   spcont(NULL),
+   last_sql_command(SQLCOM_END), spcont(NULL),
    m_parser_state(NULL),
 #ifndef EMBEDDED_LIBRARY
    audit_plugin_version(-1),
@@ -6034,7 +6034,6 @@ void THD::store_slow_query_state(Sub_statement_state *backup)
   backup->tmp_tables_size=         tmp_tables_size;
   backup->tmp_tables_used=         tmp_tables_used;
   backup->handler_stats=           handler_stats;
-  backup->stmt_changes_data=       stmt_changes_data;
 }
 
 /* Reset variables related to slow query log */
@@ -6063,7 +6062,6 @@ void THD::reset_slow_query_state(Sub_statement_state *backup)
   }
   if ((variables.log_slow_verbosity & LOG_SLOW_VERBOSITY_ENGINE))
     handler_stats.reset();
-  stmt_changes_data=            0;      // Can be used by audit plugins
 }
 
 /*
@@ -6095,7 +6093,6 @@ void THD::add_slow_query_state(Sub_statement_state *backup)
   }
   if ((variables.log_slow_verbosity & LOG_SLOW_VERBOSITY_ENGINE))
     handler_stats.add(&backup->handler_stats);
-  stmt_changes_data|=            backup->stmt_changes_data;
 }
 
 

sql/sql_class.h

@@ -2122,7 +2122,6 @@ class Sub_statement_state
   bool last_insert_id_used;
   bool in_stored_procedure;
   bool do_union;
-  bool stmt_changes_data;
   enum enum_check_fields count_cuted_fields;
 };
 
@@ -3863,7 +3862,6 @@ class THD: public THD_count, /* this must be first */
     See comment above regarding transaction_isolation.
   */
   bool              tx_read_only;
-  bool              stmt_changes_data;
   enum_check_fields count_cuted_fields;
 
   DYNAMIC_ARRAY user_var_events;        /* For user variables replication */
@@ -3998,7 +3996,7 @@ class THD: public THD_count, /* this must be first */
     execution stack when the event turns out to be ignored.
   */
   int	     slave_expected_error;
-  enum_sql_command last_sql_command;  // Last sql_command exceuted in mysql_execute_command()
+  enum_sql_command last_sql_command;  // Last sql_command executed in mysql_execute_command()
 
   sp_rcontext *spcont;		// SP runtime context
 

sql/sql_parse.cc

@@ -3515,8 +3515,6 @@ mysql_execute_command(THD *thd, bool is_called_from_prepared_stmt)
     like mysql_audit_plugin.
   */
   thd->last_sql_command= lex->sql_command;
-  thd->stmt_changes_data|= (sql_command_flags[lex->sql_command] &
-                            CF_CHANGES_DATA);
 
   /*
     Reset warning count for each query that uses tables