fix for bug#16537 (Events: mysql.event.starts is null)

- now when the event is created and STARTS is omitted then STARTS is implicitly
  CURRENT_TIMESTAMP
- This CS also fixed incorrect presentation of STARTS/ENDS in I_S.EVENTS
(incorporated review changes)


mysql-test/r/events.result:
  results of new test cases
mysql-test/t/events.test:
  new test cases for bug #16537 (Events: mysql.event.starts is null)
sql/event.cc:
  - check whether event_timed::starts_null only in case
    event_timed::expression is set, so for recurring events only
  - disable binlogging of CREATE EVENT statement. It should not be
    replicated but the result of the execution. Still the replication is
    untouched topic.
sql/event.h:
  - add flags whether starts, ends and execute_at are null or not
sql/event_executor.cc:
  - check whether xxx_null instead of !xxxx.year
sql/event_timed.cc:
  - introduce xxx_null and change the usage of xxx.year to !xxx_null
sql/sql_show.cc:
  - don't show 0000-00-00 in I_S.EVENTS when the value is NULL
sql/sql_yacc.yy:
  - if STARTS is omitted default to current_timestamp

1 files changed, 49 insertions, 1 deletions

diff --git a/mysql-test/r/events.result b/mysql-test/r/events.result
index 41f944ab089..4aedf1f57af 100644
--- a/mysql-test/r/events.result
+++ b/mysql-test/r/events.result
@@ -13,6 +13,54 @@ alter event event3 rename to event2;
 drop event event2;
 create event event2 on schedule every 2 second starts now() ends date_add(now(), interval 5 hour) comment "some" DO begin end;
 drop event event2;
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 10 SECOND COMMENT "" DO SELECT 1;
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	10	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	1	
+ALTER EVENT event_starts_test ON SCHEDULE AT '2020-02-02 20:00:02';
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	non-empty comment
+ALTER EVENT event_starts_test COMMENT "";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	
+DROP EVENT event_starts_test;
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 20 SECOND STARTS '2020-02-02 20:00:02' ENDS '2022-02-02 20:00:02' DO SELECT 2;
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	0	
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	0	non-empty comment
+ALTER EVENT event_starts_test COMMENT "";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+DROP EVENT event_starts_test;
 create event e_43 on schedule every 1 second do set @a = 5;
 set global event_scheduler = 1;
 select sleep(2);
@@ -64,7 +112,7 @@ SHOW GRANTS;
 Grants for ev_test@localhost
 GRANT USAGE ON *.* TO 'ev_test'@'localhost'
 GRANT ALL PRIVILEGES ON `events_test`.* TO 'ev_test'@'localhost'
-GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, REFERENCES, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE ON `events_test2`.* TO 'ev_test'@'localhost'
+GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, REFERENCES, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, TRIGGER ON `events_test2`.* TO 'ev_test'@'localhost'
 "Here comes an error:";
 SHOW EVENTS;
 ERROR 42000: Access denied for user 'ev_test'@'localhost' to database 'events_test2'