fix for bug #17619 Scheduler race conditions

- Scheduler is either initialized at server start or never.
  Starting & stopping is now suspending & resuming.
- The scheduler has clear OO interface
- Now all calls to the scheduler are synchronous
- GLOBAL event_scheduler uses thd::sys_var_tmp (see set_var.cc)
- External API is encapsulated into class Events
- Includes fixes for all comments of Kostja's review of 19.05.2005

Starting to merge into 5.1-release (5.1.10) and push


BitKeeper/etc/ignore:
  Added libmysqld/event_scheduler.cc to the ignore list
libmysqld/Makefile.am:
  executor -> scheduler
mysql-test/r/events.result:
  update result
mysql-test/r/events_bugs.result:
  update result
mysql-test/r/events_logs_tests.result:
  update result
mysql-test/r/events_microsec.result:
  update result
mysql-test/r/events_scheduling.result:
  update result
mysql-test/r/events_stress.result:
  update result
mysql-test/t/disabled.def:
  enable these tests
mysql-test/t/events.test:
  optimize the test a bit for speed, save some seconds runtime
  remove FULL from SHOW EVENTS
  mostly use I_S.EVENTS
mysql-test/t/events_bugs.test:
  Skip irrelevant for the current design tests - all events are loaded
  on server startup. Change in mysql.event will be visible on next server start.
  Don't use numeric error codes.
mysql-test/t/events_logs_tests.test:
  optimize the test a bit for speed
mysql-test/t/events_microsec.test:
   Skip irrelevant for the current design tests - all events are loaded
      on server startup. Change in mysql.event will be visible on next server start.
      Don't use numeric error codes.
mysql-test/t/events_scheduling.test:
  broader test
mysql-test/t/events_stress.test:
  Rework the test to the new architecture of suspending/resuming.
  Use less events, no need for thousands, hundreds is still ok.
sql/Makefile.am:
  executor -> scheduler
sql/cmakelists.txt:
  executor -> scheduler
sql/event.cc:
  - remove todo comments
  - remove unneded evex_queue abstraction functions
  - move events_init() and events_shutdown() from event_executor.cc to here
  - export db_create_event
  - remove evex_load_and_compile_event, part of class Event_scheduler
  - integrate the public interface found in event.h and used by sql_parse.cc
    to use the new class Event_scheduler.
sql/event.h:
  - add COND_finished so if one thread kills a running event it waits on this
  - export callback event_timed_definer_equal, event_timed_identifier_equal(),
    event_timed_name_equal and event_timed_db_equal()
    to be used by Event_scheduler::drop_matching_events()
  - cleanup event.h
  - encapsulated all external interface into class Events
sql/event_executor.cc:
  make it empty, will delete after that
sql/event_priv.h:
  - more things in the private header
  - remove event queue abstraction functions. tightly bind to QUEUE
  - export privately db_drop_event, db_find_event, db_create_event()
  - made change_security_context() and restore_security_context() free functions
sql/event_timed.cc:
  - fix calculation of time when ENDS is set (STARTS is always set)
  - during Event_timed::compile() set the right Security_ctx. Prevents a crash
        during Event_scheduler::load_events_from_db()
  - add Event_timed::kill_thread()
  - implement event_timed_*_equal()
  - made change_security_context() and restore_security_context() free functions.
  - Comments cleanups
sql/lex.h:
  new word scheduler for SHOW SCHEDULER STATUS (available only debug builds)
sql/log.cc:
  move these from event_scheduler.cc
sql/mysql_priv.h:
  refactor kill_one_thread
  export sql_print_message_func and sql_print_message_handlers
sql/mysqld.cc:
  In close_connections, called by kill_server() skip the main scheduler
  thread and use events_shutdown() for shutting down the scheduler, in the same
  manner it's done for RPL.
  Add a new value to --event-scheduler :
  0 <- No scheduler available
  1 <- Start with scheduler enabled
  2 <- Start with scheduler suspended
sql/repl_failsafe.cc:
  refactor thd::system_thread to be an enum
sql/set_var.cc:
  move sys_var_event_executor::update() to set_var.cc
  executor -> scheduler
  use thd::sys_var_tmp
sql/set_var.h:
  executor -> scheduler
sql/share/errmsg.txt:
  3 new error messages
sql/sql_class.cc:
  refactor thd::system_thread to be an enum . more type-safety
sql/sql_class.h:
  refactor thd::system_thread to be an enum . more type-safety
sql/sql_db.cc:
  get the error from evex_drop_schema_events
sql/sql_error.h:
  export warning_level_names
sql/sql_lex.h:
  new command SHOW SCHEDULER STATUS, available only in debug build and
  for debug purposes.
sql/sql_parse.cc:
  refactor kill_one_thread() -> does the *dirty* work, and sql_kill
  just the reporting.
  add handler for SQLCOM_SHOW_SCHEDULER_STATUS
sql/sql_show.cc:
  fix verbosity handling (this will be obsoleted anyway by the fix for 17394).
sql/sql_yacc.yy:
  remove FULL from SHOW EVENTS
  add SHOW SCHEDULER STATUS in debug builds
sql/table.cc:
  Fix valgrind warning.

1 files changed, 12 insertions, 11 deletions

diff --git a/mysql-test/r/events_logs_tests.result b/mysql-test/r/events_logs_tests.result
index ab1666fefb9..911bc8b2d60 100644
--- a/mysql-test/r/events_logs_tests.result
+++ b/mysql-test/r/events_logs_tests.result
@@ -8,7 +8,7 @@ BEGIN
 SELECT user_host, argument FROM mysql.general_log WHERE argument LIKE '%alabala%';
 END|
 "Check General Query Log"
-SET GLOBAL event_scheduler=0;
+SET GLOBAL event_scheduler=2;
 create event log_general on schedule every 1 minute do SELect 'alabala', sleep(3) from dual;
 TRUNCATE mysql.general_log;
 "1 row, the current statement!"
@@ -22,7 +22,7 @@ user_host	argument
 root[root] @ localhost [localhost]	SELect 'alabala', sleep(3) from dual
 DROP PROCEDURE select_general_log;
 DROP EVENT log_general;
-SET GLOBAL event_scheduler=0;
+SET GLOBAL event_scheduler=2;
 "Check slow query log"
 "Save the values"
 SET @old_global_long_query_time:=(select get_value());
@@ -36,14 +36,14 @@ SELECT user_host, query_time, db, sql_text FROM mysql.slow_log;
 user_host	query_time	db	sql_text
 "Set new values"
 SET GLOBAL long_query_time=4;
-SET SESSION long_query_time=2;
+SET SESSION long_query_time=1;
 "Check that logging is working"
-SELECT SLEEP(3);
-SLEEP(3)
+SELECT SLEEP(2);
+SLEEP(2)
 0
 SELECT user_host, query_time, db, sql_text FROM mysql.slow_log;
 user_host	query_time	db	sql_text
-root[root] @ localhost []	SLEEPVAL	events_test	SELECT SLEEP(3)
+root[root] @ localhost []	SLEEPVAL	events_test	SELECT SLEEP(2)
 TRUNCATE mysql.slow_log;
 CREATE TABLE slow_event_test (slo_val tinyint, val tinyint);
 "This won't go to the slow log"
@@ -54,7 +54,7 @@ SET GLOBAL event_scheduler=1;
 "Sleep some more time than the actual event run will take"
 SHOW VARIABLES LIKE 'event_scheduler';
 Variable_name	Value
-event_scheduler	ON
+event_scheduler	1
 "Check our table. Should see 1 row"
 SELECT * FROM slow_event_test;
 slo_val	val
@@ -64,18 +64,19 @@ SELECT user_host, query_time, db, sql_text FROM mysql.slow_log;
 user_host	query_time	db	sql_text
 "This should go to the slow log"
 SET SESSION long_query_time=10;
+SET GLOBAL long_query_time=1;
 DROP EVENT long_event;
-CREATE EVENT long_event2 ON SCHEDULE EVERY 1 MINUTE DO INSERT INTO slow_event_test SELECT @@long_query_time, SLEEP(5);
+CREATE EVENT long_event2 ON SCHEDULE EVERY 1 MINUTE DO INSERT INTO slow_event_test SELECT @@long_query_time, SLEEP(2);
 "Sleep some more time than the actual event run will take"
 "Check our table. Should see 2 rows"
 SELECT * FROM slow_event_test;
 slo_val	val
 4	0
-4	0
-"Check slow log. Should see 1 row because 5 is over the threshold of 4 for GLOBAL, though under SESSION which is 10"
+1	0
+"Check slow log. Should see 1 row because 4 is over the threshold of 3 for GLOBAL, though under SESSION which is 10"
 SELECT user_host, query_time, db, sql_text FROM mysql.slow_log;
 user_host	query_time	db	sql_text
-root[root] @ localhost [localhost]	SLEEPVAL	events_test	INSERT INTO slow_event_test SELECT @@long_query_time, SLEEP(5)
+root[root] @ localhost [localhost]	SLEEPVAL	events_test	INSERT INTO slow_event_test SELECT @@long_query_time, SLEEP(2)
 DROP EVENT long_event2;
 SET GLOBAL  long_query_time =@old_global_long_query_time;
 SET SESSION long_query_time =@old_session_long_query_time;