Fixed bug#11764334 (formerly bug#57156): ALTER EVENT CHANGES

THE EVENT STATUS.

Any ALTER EVENT statement on a disabled event enabled it back
(unless this ALTER EVENT statement explicitly disabled the event).

The problem was that during processing of an ALTER EVENT statement
value of status field was overwritten unconditionally even if new
value was not specified explicitly. As a consequence this field
was set to default value for status which corresponds to ENABLE.

The solution is to check if status field was explicitly specified in
ALTER EVENT statement before assigning new value to status field.

mysql-test/r/events_bugs.result:
  test's result for Bug#11764334 was added.
mysql-test/t/events_bugs.test:
  new test for Bug#11764334 was added.
sql/event_db_repository.cc:
  mysql_event_fill_row() was modified: set value for status field
  in events tables only in case if statement CREATE EVENT
  is being processed or if this value was set in ALTER EVENT
  statement.
  Event_db_repository::create_event was modified: removed redundant
  setting of status field after return from call to mysql_event_fill_row().
sql/event_parse_data.h:
  Event_parse_data structure was modified: added flag
  status_changed that is set to true if status's value
  was changed in ALTER EVENT statement.
sql/sql_yacc.yy:
  Set flag status_changed if status was set in ALTER EVENT
  statement.

mysql-test/r/events_bugs.result

@@ -419,7 +419,7 @@ SET TIME_ZONE= '+04:00';
 ALTER EVENT e1 DO SELECT 2;
 SHOW EVENTS;
 Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status	Originator	character_set_client	collation_connection	Database Collation
-events_test	e1	root@localhost	-03:00	RECURRING	NULL	1	DAY	2005-12-31 20:58:59	2030-01-03 00:00:00	ENABLED	1	latin1	latin1_swedish_ci	latin1_swedish_ci
+events_test	e1	root@localhost	-03:00	RECURRING	NULL	1	DAY	2005-12-31 20:58:59	2030-01-03 00:00:00	DISABLED	1	latin1	latin1_swedish_ci	latin1_swedish_ci
 DROP EVENT e1;
 SET TIME_ZONE='+05:00';
 CREATE EVENT e1 ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' DO
@@ -796,6 +796,20 @@ COUNT(*)
 DROP EVENT IF EXISTS event_Bug12546938;
 DROP TABLE table_bug12546938;
 SET GLOBAL EVENT_SCHEDULER = OFF;
+DROP DATABASE IF EXISTS event_test11764334;
+CREATE DATABASE event_test11764334;
+USE event_test11764334;
+CREATE EVENT ev1 ON SCHEDULE EVERY 3 SECOND DISABLE DO SELECT 1;
+SHOW EVENTS IN event_test11764334 WHERE NAME='ev1';
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status	Originator	character_set_client	collation_connection	Database Collation
+event_test11764334	ev1	root@localhost	SYSTEM	RECURRING	NULL	3	SECOND	2011-06-09 19:59:01	NULL	DISABLED	1	latin1	latin1_swedish_ci	latin1_swedish_ci
+ALTER EVENT ev1 ON SCHEDULE EVERY 4 SECOND;
+SHOW EVENTS IN event_test11764334 WHERE NAME='ev1';
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status	Originator	character_set_client	collation_connection	Database Collation
+event_test11764334	ev1	root@localhost	SYSTEM	RECURRING	NULL	4	SECOND	2011-06-09 19:59:01	NULL	DISABLED	1	latin1	latin1_swedish_ci	latin1_swedish_ci
+DROP EVENT ev1;
+DROP DATABASE event_test11764334;
+USE test;
 DROP DATABASE events_test;
 SET GLOBAL event_scheduler= 'ON';
 SET @@global.concurrent_insert= @concurrent_insert;

mysql-test/t/events_bugs.test

@@ -1286,6 +1286,21 @@ DROP EVENT IF EXISTS event_Bug12546938;
 DROP TABLE table_bug12546938;
 SET GLOBAL EVENT_SCHEDULER = OFF;
 
+#
+# Bug#11764334 - 57156: ALTER EVENT CHANGES THE EVENT STATUS
+#
+--disable_warnings
+DROP DATABASE IF EXISTS event_test11764334;
+--enable_warnings
+CREATE DATABASE event_test11764334;
+USE event_test11764334;
+CREATE EVENT ev1 ON SCHEDULE EVERY 3 SECOND DISABLE DO SELECT 1;
+SHOW EVENTS IN event_test11764334 WHERE NAME='ev1';
+ALTER EVENT ev1 ON SCHEDULE EVERY 4 SECOND;
+SHOW EVENTS IN event_test11764334 WHERE NAME='ev1';
+DROP EVENT ev1;
+DROP DATABASE event_test11764334;
+USE test; 
 ###########################################################################
 #
 # End of tests

sql/event_db_repository.cc

@@ -226,9 +226,16 @@ mysql_event_fill_row(THD *thd,
   if (fields[f_num= ET_FIELD_NAME]->store(et->name.str, et->name.length, scs))
     goto err_truncate;
 
-  /* both ON_COMPLETION and STATUS are NOT NULL thus not calling set_notnull()*/
+  /* ON_COMPLETION field is NOT NULL thus not calling set_notnull()*/
   rs|= fields[ET_FIELD_ON_COMPLETION]->store((longlong)et->on_completion, TRUE);
-  rs|= fields[ET_FIELD_STATUS]->store((longlong)et->status, TRUE);
+
+  /*
+    Set STATUS value unconditionally in case of CREATE EVENT.
+    For ALTER EVENT set it only if value of this field was changed.
+    Since STATUS field is NOT NULL call to set_notnull() is not needed.
+  */
+  if (!is_update || et->status_changed)
+    rs|= fields[ET_FIELD_STATUS]->store((longlong)et->status, TRUE);
   rs|= fields[ET_FIELD_ORIGINATOR]->store((longlong)et->originator, TRUE);
 
   /*
@@ -694,8 +701,6 @@ Event_db_repository::create_event(THD *thd, Event_parse_data *parse_data,
   if (mysql_event_fill_row(thd, table, parse_data, sp, saved_mode, FALSE))
     goto end;
 
-  table->field[ET_FIELD_STATUS]->store((longlong)parse_data->status, TRUE);
-
   if ((ret= table->file->ha_write_row(table->record[0])))
   {
     table->file->print_error(ret, MYF(0));

sql/event_parse_data.cc

@@ -46,9 +46,8 @@ Event_parse_data::new_instance(THD *thd)
 
 Event_parse_data::Event_parse_data()
   :on_completion(Event_parse_data::ON_COMPLETION_DEFAULT),
-  status(Event_parse_data::ENABLED),
-  do_not_create(FALSE),
-  body_changed(FALSE),
+  status(Event_parse_data::ENABLED), status_changed(false),
+  do_not_create(FALSE), body_changed(FALSE),
   item_starts(NULL), item_ends(NULL), item_execute_at(NULL),
   starts_null(TRUE), ends_null(TRUE), execute_at_null(TRUE),
   item_expression(NULL), expression(0)
@@ -140,6 +139,7 @@ Event_parse_data::check_if_in_the_past(THD *thd, my_time_t ltime_utc)
   else if (status == Event_parse_data::ENABLED)
   {
     status= Event_parse_data::DISABLED;
+    status_changed= true;
     push_warning(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
                  ER_EVENT_EXEC_TIME_IN_THE_PAST,
                  ER(ER_EVENT_EXEC_TIME_IN_THE_PAST));
@@ -569,7 +569,10 @@ void Event_parse_data::check_originator_id(THD *thd)
     DBUG_PRINT("info", ("Invoked object status set to SLAVESIDE_DISABLED."));
     if ((status == Event_parse_data::ENABLED) ||
         (status == Event_parse_data::DISABLED))
-      status = Event_parse_data::SLAVESIDE_DISABLED;
+    {
+      status= Event_parse_data::SLAVESIDE_DISABLED;
+      status_changed= true;
+    }
     originator = thd->server_id;
   }
   else

sql/event_parse_data.h

@@ -49,6 +49,7 @@ class Event_parse_data : public Sql_alloc
 
   int on_completion;
   int status;
+  bool status_changed;
   longlong originator;
   /*
     do_not_create will be set if STARTS time is in the past and

sql/sql_yacc.yy

@@ -2024,16 +2024,19 @@ opt_ev_status:
         | ENABLE_SYM
           {
             Lex->event_parse_data->status= Event_parse_data::ENABLED;
+            Lex->event_parse_data->status_changed= true;
             $$= 1;
           }
         | DISABLE_SYM ON SLAVE
           {
             Lex->event_parse_data->status= Event_parse_data::SLAVESIDE_DISABLED;
+            Lex->event_parse_data->status_changed= true; 
             $$= 1;
           }
         | DISABLE_SYM
           {
             Lex->event_parse_data->status= Event_parse_data::DISABLED;
+            Lex->event_parse_data->status_changed= true;
             $$= 1;
           }
         ;