A set of changes aiming to make the Event Scheduler more user-friendly

when there are no up-to-date system tables to support it:
 - initialize the scheduler before reporting "Ready for connections".
   This ensures that warnings, if any, are printed before "Ready for
   connections", and this message is not mangled.
 - do not abort the scheduler if there are no system tables
 - check the tables once at start up, remember the status and disable
   the scheduler if the tables are not up to date.
   If one attempts to use the scheduler with bad tables,
   issue an error message.
 - clean up the behaviour of the module under LOCK TABLES and pre-locking
   mode
 - make sure implicit commit of Events DDL works as expected.
 - add more tests


Collateral clean ups in the events code.

This patch fixes Bug#23631 Events: SHOW VARIABLES doesn't work 
when mysql.event is damaged


mysql-test/r/events.result:
  Update results.
mysql-test/r/events_bugs.result:
  Update results.
mysql-test/r/events_restart_phase1.result:
  Update results.
mysql-test/r/events_restart_phase2.result:
  Update results.
mysql-test/r/events_restart_phase3.result:
  Update results.
mysql-test/r/events_scheduling.result:
  Update results.
mysql-test/r/events_time_zone.result:
  Update results.
mysql-test/t/events.test:
  Add new tests for tampering with mysql.event and some more
  tests for sub-statements, LOCK TABLES mode and pre-locking.
mysql-test/t/events_bugs.test:
  Move the non-concurrent part of test for Bug 16420 to this file.
mysql-test/t/events_restart_phase1.test:
  Rewrite events_restart_* tests to take into account that now
  we check mysql.event table only once, at server startup.
mysql-test/t/events_restart_phase2.test:
  Rewrite events_restart_* tests to take into account that now
  we check mysql.event table only once, at server startup.
mysql-test/t/events_restart_phase3.test:
  Rewrite events_restart_* tests to take into account that now
  we check mysql.event table only once, at server startup.
mysql-test/t/events_scheduling.test:
  Add more coverage for event_scheduler global variable.
mysql-test/t/events_time_zone.test:
  Move the non-concurrent part of the tests for Bug 16420 to 
  events_bugs.test
sql/event_data_objects.cc:
  Move update_timing_fields functionality to Event_db_repository.
  Make loading of events from a table record more robust to tampering
  with the table - now we do not check mysql.event on every table open.
sql/event_data_objects.h:
  Cleanup.
sql/event_db_repository.cc:
  Now Event_db_repository is responsible for table I/O only.
  All the logic of events DDL is handled outside, in Events class please
  refer to the added test coverage to see how this change affected
  the behavior of Event Scheduler.
  Dependency on sp_head.h and sp.h removed.
  Make this module robust to tweaks with mysql.event table.
  Move check_system_tables from events.cc to this file
sql/event_db_repository.h:
  Cleanup declarations (remove unused ones, change return type to bool
  from int).
sql/event_queue.cc:
  Update to adapt to the new start up scheme of the Event Scheduler.
sql/event_queue.h:
  Cleanup declarations.
sql/event_scheduler.cc:
  Make all the error messages uniform:
  [SEVERITY] Event Scheduler: [user][schema.event] message
  Using append_identifier for error logging was an overkill - we may 
  need it only if the system character set may have NUL (null character)
  as part of a valid identifier, this is currently never the case, 
  whereas additional quoting did not look nice in the log.
sql/event_scheduler.h:
  Cleanup the headers.
sql/events.cc:
  Use a different start up procedure of Event Scheduler:
  - at start up, try to check the system tables first.
  If they are not up-to-date, disable the scheduler.
  - try to load all the active events. In case of a load error, abort
  start up.
  - do not parse an event on start up. Parsing only gives some information
  about event validity, but far not all.
  Consolidate the business logic of Events DDL in this module.
  Now opt_event_scheduler may change after start up and thus is protected
  by LOCK_event_metadata mutex.
sql/events.h:
  Use all-static-data-members approach to implement Singleton pattern.
sql/mysqld.cc:
  New invocation scheme of Events. Move some logic to events.cc.
  Initialize the scheduler before reporting "Ready for connections".
sql/set_var.cc:
  Clean up sys_var_thd_sql_mode::symbolic_mode_representation
  to work with a LEX_STRING.
  Move more logic related to @@events_scheduler global variable to Events
  module.
sql/set_var.h:
  Update declarations.
sql/share/errmsg.txt:
  If someone tampered with mysql.event table after the server has
  started we no longer give him/her a complete report what was actually 
  broken. Do not send the user to look at the error log in such case,
  as there is nothing there (check_table_intact is not executed).
sql/sp_head.cc:
  Update to a new declaration of 
  sys_var_thd_sql_mode::symbolic_mode_representation
sql/sql_db.cc:
  New invocation scheme of Events module.
sql/sql_parse.cc:
  Move more logic to Events module. Make sure that we are consistent
  in the way access rights are checked for Events DDL: always
  after committing the current transaction and checking the system tables.
sql/sql_show.cc:
  Update to the new declarations of 
  sys_var_thd_sql_mode::symbolic_mode_representation
sql/sql_test.cc:
  New invocation scheme of events.
sql/table.cc:
  mysql.event is a system table.
  Update check_table_intact to be concurrent, more verbose, and less smart.
sql/table.h:
  Add a helper method.
mysql-test/r/events_trans.result:
  New BitKeeper file ``mysql-test/r/events_trans.result''
mysql-test/t/events_trans.test:
  New BitKeeper file ``mysql-test/t/events_trans.test'':
  test cases for Event Scheduler that require a transactional
  storage engine.

1 files changed, 149 insertions, 1 deletions

diff --git a/mysql-test/r/events_bugs.result b/mysql-test/r/events_bugs.result
index 6835ecd7fde..b7690a57207 100644
--- a/mysql-test/r/events_bugs.result
+++ b/mysql-test/r/events_bugs.result
@@ -1,4 +1,7 @@
-create database if not exists events_test;
+drop database if exists events_test;
+drop database if exists mysqltest_db1;
+drop database if exists mysqltest_db2;
+create database events_test;
 use events_test;
 CREATE EVENT lower_case ON SCHEDULE EVERY 1 MINUTE DO SELECT 1;
 CREATE EVENT Lower_case ON SCHEDULE EVERY 2 MINUTE DO SELECT 2;
@@ -381,4 +384,149 @@ ERROR 42000: Access denied; you need the SUPER privilege for this operation
 DROP EVENT e1;
 ERROR HY000: Unknown event 'e1'
 DROP USER mysqltest_u1@localhost;
+SET GLOBAL EVENT_SCHEDULER= OFF;
+SET @save_time_zone= @@TIME_ZONE;
+SET TIME_ZONE= '+00:00';
+SET TIMESTAMP= UNIX_TIMESTAMP('2005-12-31 23:58:59');
+CREATE EVENT e1 ON SCHEDULE EVERY 1 DAY DO SELECT 1;
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	+00:00	RECURRING	NULL	1	DAY	2005-12-31 23:58:59	NULL	ENABLED
+SET TIME_ZONE= '-01:00';
+ALTER EVENT e1 ON SCHEDULE EVERY 1 DAY STARTS '2000-01-01 00:00:00';
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	-01:00	RECURRING	NULL	1	DAY	2000-01-01 00:00:00	NULL	ENABLED
+SET TIME_ZONE= '+02:00';
+ALTER EVENT e1 ON SCHEDULE AT '2000-01-02 00:00:00'
+  ON COMPLETION PRESERVE DISABLE;
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	+02:00	ONE TIME	2000-01-02 00:00:00	NULL	NULL	NULL	NULL	DISABLED
+SET TIME_ZONE= '-03:00';
+ALTER EVENT e1 ON SCHEDULE EVERY 1 DAY ENDS '2030-01-03 00:00:00'
+  ON COMPLETION PRESERVE DISABLE;
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	-03:00	RECURRING	NULL	1	DAY	2005-12-31 20:58:59	2030-01-03 00:00:00	DISABLED
+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
+events_test	e1	root@localhost	-03:00	RECURRING	NULL	1	DAY	2005-12-31 20:58:59	2030-01-03 00:00:00	ENABLED
+DROP EVENT e1;
+SET TIME_ZONE='+05:00';
+CREATE EVENT e1 ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' DO
+SELECT 1;
+SET TIMESTAMP= @@TIMESTAMP + 1;
+SET TIME_ZONE='-05:00';
+CREATE EVENT e2 ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' DO
+SELECT 1;
+SET TIMESTAMP= @@TIMESTAMP + 1;
+SET TIME_ZONE='+00:00';
+CREATE EVENT e3 ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' DO
+SELECT 1;
+SELECT * FROM INFORMATION_SCHEMA.EVENTS ORDER BY event_name;
+EVENT_CATALOG	EVENT_SCHEMA	EVENT_NAME	DEFINER	TIME_ZONE	EVENT_BODY	EVENT_DEFINITION	EVENT_TYPE	EXECUTE_AT	INTERVAL_VALUE	INTERVAL_FIELD	SQL_MODE	STARTS	ENDS	STATUS	ON_COMPLETION	CREATED	LAST_ALTERED	LAST_EXECUTED	EVENT_COMMENT
+NULL	events_test	e1	root@localhost	+05:00	SQL	SELECT 1	RECURRING	NULL	1	DAY		2006-01-01 00:00:00	NULL	ENABLED	NOT PRESERVE	2005-12-31 23:58:59	2005-12-31 23:58:59	NULL	
+NULL	events_test	e2	root@localhost	-05:00	SQL	SELECT 1	RECURRING	NULL	1	DAY		2006-01-01 00:00:00	NULL	ENABLED	NOT PRESERVE	2005-12-31 23:59:00	2005-12-31 23:59:00	NULL	
+NULL	events_test	e3	root@localhost	+00:00	SQL	SELECT 1	RECURRING	NULL	1	DAY		2006-01-01 00:00:00	NULL	ENABLED	NOT PRESERVE	2005-12-31 23:59:01	2005-12-31 23:59:01	NULL	
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	+05:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+events_test	e2	root@localhost	-05:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+events_test	e3	root@localhost	+00:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+SHOW CREATE EVENT e1;
+Event	sql_mode	time_zone	Create Event
+e1		+05:00	CREATE EVENT `e1` ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' ON COMPLETION NOT PRESERVE ENABLE DO SELECT 1
+SHOW CREATE EVENT e2;
+Event	sql_mode	time_zone	Create Event
+e2		-05:00	CREATE EVENT `e2` ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' ON COMPLETION NOT PRESERVE ENABLE DO SELECT 1
+SHOW CREATE EVENT e3;
+Event	sql_mode	time_zone	Create Event
+e3		+00:00	CREATE EVENT `e3` ON SCHEDULE EVERY 1 DAY STARTS '2006-01-01 00:00:00' ON COMPLETION NOT PRESERVE ENABLE DO SELECT 1
+The following should fail, and nothing should be altered.
+ALTER EVENT e1 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00';
+ERROR HY000: Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been altered
+ALTER EVENT e1 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' DISABLE;
+ERROR HY000: Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been altered
+The following should give warnings, and nothing should be created.
+CREATE EVENT e4 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00'
+DO
+SELECT 1;
+Warnings:
+Note	1584	Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been created
+CREATE EVENT e4 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' DISABLE
+DO
+SELECT 1;
+Warnings:
+Note	1584	Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been created
+CREATE EVENT e4 ON SCHEDULE AT '1999-01-01 00:00:00' DO
+SELECT 1;
+Warnings:
+Note	1584	Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been created
+CREATE EVENT e4 ON SCHEDULE AT '1999-01-01 00:00:00' DISABLE
+DO
+SELECT 1;
+Warnings:
+Note	1584	Event execution time is in the past and ON COMPLETION NOT PRESERVE is set. Event has not been created
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	+05:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+events_test	e2	root@localhost	-05:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+events_test	e3	root@localhost	+00:00	RECURRING	NULL	1	DAY	2006-01-01 00:00:00	NULL	ENABLED
+The following should succeed giving a warning.
+ALTER EVENT e1 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' ON COMPLETION PRESERVE;
+Warnings:
+Note	1533	Event execution time is in the past. Event has been disabled
+CREATE EVENT e4 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' ON COMPLETION PRESERVE
+DO
+SELECT 1;
+Warnings:
+Note	1533	Event execution time is in the past. Event has been disabled
+CREATE EVENT e5 ON SCHEDULE AT '1999-01-01 00:00:00'
+  ON COMPLETION PRESERVE
+DO
+SELECT 1;
+Warnings:
+Note	1533	Event execution time is in the past. Event has been disabled
+The following should succeed without warnings.
+ALTER EVENT e2 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00';
+ALTER EVENT e3 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' ON COMPLETION PRESERVE DISABLE;
+CREATE EVENT e6 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00' DO
+SELECT 1;
+CREATE EVENT e7 ON SCHEDULE EVERY 1 HOUR STARTS '1999-01-01 00:00:00'
+  ENDS '1999-01-02 00:00:00' ON COMPLETION PRESERVE DISABLE
+DO
+SELECT 1;
+CREATE EVENT e8 ON SCHEDULE AT '1999-01-01 00:00:00'
+  ON COMPLETION PRESERVE DISABLE
+DO
+SELECT 1;
+SHOW EVENTS;
+Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	e1	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	1999-01-02 00:00:00	DISABLED
+events_test	e2	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	NULL	ENABLED
+events_test	e3	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	1999-01-02 00:00:00	DISABLED
+events_test	e4	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	1999-01-02 00:00:00	DISABLED
+events_test	e5	root@localhost	+00:00	ONE TIME	1999-01-01 00:00:00	NULL	NULL	NULL	NULL	DISABLED
+events_test	e6	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	NULL	ENABLED
+events_test	e7	root@localhost	+00:00	RECURRING	NULL	1	HOUR	1999-01-01 00:00:00	1999-01-02 00:00:00	DISABLED
+events_test	e8	root@localhost	+00:00	ONE TIME	1999-01-01 00:00:00	NULL	NULL	NULL	NULL	DISABLED
+DROP EVENT e8;
+DROP EVENT e7;
+DROP EVENT e6;
+DROP EVENT e5;
+DROP EVENT e4;
+DROP EVENT e3;
+DROP EVENT e2;
+DROP EVENT e1;
+SET TIME_ZONE=@save_time_zone;
 drop database events_test;