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- 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 spee...

(one patch)


mysql-test/r/events_bugs.result:
  fix for bug 16408
mysql-test/t/events_bugs.test:
  fix for bug 16408
sql/event.h:
  fix for bug 16408
sql/event_timed.cc:
  fix for bug 16408
sql/sql_parse.cc:
  fix for bug 16408
sql/sql_yacc.yy:
  fix for bug 16408

fix for bug#17793 (Scheduler uses class event_timed should be Event_timed)


sql/event.cc:
  class event_timed -> Event_timed
sql/event.h:
  class event_timed -> Event_timed
sql/event_executor.cc:
  class event_timed -> Event_timed
sql/event_priv.h:
  class event_timed -> Event_timed
sql/event_timed.cc:
  class event_timed -> Event_timed
sql/sql_lex.h:
  class event_timed -> Event_timed
sql/sql_show.cc:
  class event_timed -> Event_timed
sql/sql_yacc.yy:
  class event_timed -> Event_timed

- 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

WL#1032
sql_mode setting was disregarded during create/alter event and wasn't set during
event execution.
(post-review small fixes)


sql/event.cc:
  store the sql_mode when the body is stored
  - always on create event
  - during alter event if the user changes the body
sql/event.h:
  add sql_mode as member variable
sql/event_timed.cc:
  - exchange thd->variables.sql_mode before and after execution
  - set the sql_mode of the anonymous SP -> event_timed::sphead
sql/sql_show.cc:
  - show real content in I_S.EVENTS.SQL_MODE , disallow NULL

WL#1034


mysql-test/r/events.result:
  output fix
sql/event.cc:
  - handle also INTERVAL_MICROSECOND, was missing.
  - use renamed ER_ code which is generic
sql/event.h:
  add new error code
sql/event_executor.cc:
  - use new ER_ code name
  - handle EVEX_MICROSECOND_UNSUP error code
sql/event_timed.cc:
  forbid MICROSECOND intervals for events
sql/share/errmsg.txt:
  rename error code, it's generic
sql/sql_show.cc:
  use new error code name
sql/sql_yacc.yy:
  bail out if any MICROSECOND interval is specified

(pre-push)


mysql-test/r/events.result:
  update result
mysql-test/t/events.test:
  few more tests
sql/event.cc:
  fix compilation failure after big merge
sql/event.h:
  initialize s_ctx to be the context to be used.
  don't use sphead->m_security_ctx but we will copy 
  the initted ctx to there
sql/event_timed.cc:
  -initialize s_ctx to be the context to be used.
  don't use sphead->m_security_ctx but we will copy 
  the initted ctx to there
  
  - first init the context
  - then compile the event
  - and then copy the context
  - don't use mysql_change_db() for now change_security_context() gets the
    right context info

WL#1034
- This changeset also changes the executor so its quite more stable now.
  Stressing test case added that executes ~800 events per second and dropping
  hundreds of events at once using DROP DATABASE.
(with fixes after review of JimW)
(with fixes after review of Serg)


mysql-test/r/events.result:
  update results after TRIGGER_ACL was added
mysql-test/t/events.test:
  -redundant line
sql/event.cc:
  Implemented evex_db_drop_events() which drops all events
  from a specific database. Needed for SQLCOM_DROP_DATABASE
sql/event.h:
  - protect the event better (see the changes to event_executor.cc
    and event.cc). An event object could be used in a spawned thread
    before it's executed but till now the object is marked as being
    executed when the anonymous sp_head is executed. However, there are
    timeframes before and after that during which the event is not marked
    as executed and other thread may delete the object -> so we end with
    a nirvana pointer.
sql/event_executor.cc:
  - extract some of the code executed in the main thread to a function. Too long
    functions are bad for the overview.
  - prepend all information/error messages to the console with "SCHEDULER:" for
    better overview, and easied searching in the log tables.
sql/event_priv.h:
  - change the name, of evex_db_find_event_by_name() and don't
    used C++ features like function overloading
  - define consts for result returned from event_timed::spawn_now()
sql/event_timed.cc:
  - add few methods related to event execution.
    now the event spawns the worker thread and
    passes itself as parameter. This way it locks itself for exectution
    first and then spawning -> no race condition. When the worker thread
    has finished working with the reference it calls back
    event_timed::spawn_thread_finish() to unlock itself.
sql/sql_db.cc:
  - call evex_drop_db_events() on DROP DATABASE

- fix for bug#16423 (Events: SHOW CREATE EVENT doesn't work)
- this Changeset commits makes CREATE/UPDATE/DELETE EVENT real DDL statements
  by committing the currently open transaction before they are executed.
- this Changeset also fixes a trailing space problem since the very early days
  of the internal cron
- adds sophisticated checking of whether mysql.event was tampered accidentally
  or with purpose by an user.
- adds a lot of inline function documentation - documents everything left
  uncodumented
- INTERVAL_XXXX to XXX in I_S.EVENTS.INTERVAL_FIELD

WL#1034 (Internal CRON)


mysql-test/r/events.result:
  update result
mysql-test/t/events.test:
  add test cases for SHOW CREATE EVENT
  add test cases where the structure of mysql.event is changed and error reporting in this case
sql/event.cc:
  - do a lot more checking on mysql.event whether it's valid
    introduced generic function table_check_intact() which can be used also
    for checking whether a system table (mysql.*) has been tampered by user
    and report an error in this case. The checking is quite strict, thus
    maybe some mechanism can be added later that loosens this like some
    session variable, for instance, i_am_aware_that_i_can_damage_my_data
    so the table will be opened nevertheless we think that it's not valid.
  - add evex_show_create_event(THD *thd, sp_name *spn, LEX_STRING definer)
  - document a loooot. not a single function left undocumented.
sql/event.h:
  - add evex_show_create_event(THD *thd, sp_name *spn, LEX_STRING definer)
  - change get_show_create_event() to get_create_event()
  - add TABLE_FIELD_W_TYPE used by table_check_intact()
  - add event_timed::sql_mode so it can be used by show create event. currently
    always 0, will be fixed by a patch for another bug. At least makes the code
    of show create event complete.
sql/event_executor.cc:
  - add evex_check_system_tables() that checks on boot and event
    main thread startup that mysql.db and mysql.user tables are correct.
  - document everything!
sql/event_priv.h:
  remove a line
sql/event_timed.cc:
  - implement SHOW CREATE EVENT
  - document undocumented functions!
sql/share/errmsg.txt:
  - fix an error message and add two new
sql/sql_acl.cc:
  - add mysql.db table definition to use by table_check_intact()
  - exchange some of the positions by numbers from mysql.db to enum names (see sql_acl.h)
sql/sql_acl.h:
  - define the structure of mysql.db table
sql/sql_parse.cc:
  - handle SQLCOM_SHOW_CREATE_EVENT
  - end the current transaction becase CREATE/UPDATE/DELETE EVENT is a DDL
    statement
sql/sql_show.cc:
  - remove interval_type_to_name
  - use common function event_reconstruct_interval_expression()
    that reconstructs the expression given at create/alter, to some
    extent - interval of 2:62 MINUTE_SECOND will be reconstructed as
    interval of 3:02 MINUTE_SECOND!
sql/sql_yacc.yy:
  init the definer of event_timed also when doing SHOW CREATE EVENT
  because it's needed for checking into mysql.event
sql/table.cc:
  - remove stale code. only mysql.event should be a 'system_table'
  - add table_check_intact() to check the consistency of a table.
    mostly usable with mysql.xxx tables.
sql/table.h:
  - export TABLE_FIELD_W_TYPE and table_check_intact() which are used for 
    checking the structure of a table. mostly usable for mysql.xxx tables.

Events were executed with all privileges possible on planet Earth :(
WL#1034


mysql-test/r/events.result:
  update test results
mysql-test/t/events.test:
  test for bug#17289 Events: missing privilege check for drop database
sql/event.h:
  -add two new methods to event_timed to change and restore
   the security context
sql/event_executor.cc:
  - move code regarding privilieges checking to event_timed::execute()
  - add a new function evex_print_warnings() which prints the notes/warnings/errors
    to the console (easily capturable with logs-into-tables) so one can see what
    has happened if there was an error of some sort!
sql/event_timed.cc:
  - fix documentation
  - add a new error code -99, EVENT was revoked from the user on the DB
  - set_sec_ctx, execute, restore_sex_ctx
sql/sql_error.cc:
  - make warning_level_names public to be used in event_executor.cc
  - change from 2 arrays to a LEX_STRING array

post-push fix for bug#16407 (sql_mode discarded)
WL#1034 (Internal CRON)

post-review change - use pointer instead of copy on the stack.
WL#1034 (Internal CRON)
 This patch adds INFORMATION_SCHEMA.EVENTS table with the following format:
  EVENT_CATALOG  - MYSQL_TYPE_STRING  (Always NULL)
  EVENT_SCHEMA   - MYSQL_TYPE_STRING  (the database)
  EVENT_NAME     - MYSQL_TYPE_STRING  (the name)
  DEFINER        - MYSQL_TYPE_STRING  (user@host)
  EVENT_BODY     - MYSQL_TYPE_STRING  (the body from mysql.event)
  EVENT_TYPE     - MYSQL_TYPE_STRING  ("ONE TIME" | "RECURRING")
  EXECUTE_AT     - MYSQL_TYPE_TIMESTAMP (set for "ONE TIME" otherwise NULL)
  INTERVAL_VALUE - MYSQL_TYPE_LONG    (set for RECURRING otherwise NULL)
  INTERVAL_FIELD - MYSQL_TYPE_STRING  (set for RECURRING otherwise NULL)
  SQL_MODE       - MYSQL_TYPE_STRING  (for now NULL)
  STARTS         - MYSQL_TYPE_TIMESTAMP (starts from mysql.event)
  ENDS           - MYSQL_TYPE_TIMESTAMP (ends from mysql.event)
  STATUS         - MYSQL_TYPE_STRING  (ENABLED | DISABLED)
  ON_COMPLETION  - MYSQL_TYPE_STRING  (NOT PRESERVE | PRESERVE)
  CREATED        - MYSQL_TYPE_TIMESTAMP
  LAST_ALTERED   - MYSQL_TYPE_TIMESTAMP
  LAST_EXECUTED  - MYSQL_TYPE_TIMESTAMP
  EVENT_COMMENT  - MYSQL_TYPE_STRING

  SQL_MODE is NULL for now, because the value is still not stored in mysql.event .
Support will be added as a fix for another bug.

 This patch also adds SHOW [FULL] EVENTS [FROM db] [LIKE pattern]
1. SHOW EVENTS shows always only the events on the same user,
   because the PK of mysql.event is (definer, db, name) several 
   users may have event with the same name -> no information disclosure.
2. SHOW FULL EVENTS - shows the events (in the current db as SHOW EVENTS)
   of all users. The user has to have PROCESS privilege, if not then
   SHOW FULL EVENTS behave like SHOW EVENTS.
3. If [FROM db] is specified then this db is considered.
4. Event names can be filtered with LIKE pattern.
  SHOW EVENTS returns table with the following columns, which are subset of
  the data which is returned by SELECT * FROM I_S.EVENTS
   Db
   Name
   Definer 
   Type
   Execute at
   Interval value
   Interval field 
   Starts 
   Ends
   Status


mysql-test/lib/init_db.sql:
  change the PK - (definer, db, name)
  quicker searches when SHOW EVENTS;
  allow also different users to have events with the same name -> 
  no information disclosure
mysql-test/r/events.result:
  result of new tests
mysql-test/r/information_schema.result:
  result of new tests
mysql-test/r/information_schema_db.result:
  result of new tests
mysql-test/r/system_mysql_db.result:
  result of new tests
mysql-test/t/events.test:
  new tests for information_schema.events
scripts/mysql_create_system_tables.sh:
  change the PK of mysql.event to (definer, db, name)
scripts/mysql_fix_privilege_tables.sql:
  change the PK of mysql.event to (definer, db, name)
sql/event.cc:
  pass around the definer of the event because of the new PK
  which is (definer, db, name). It's needed for index searching.
sql/event.h:
  - make enum evex_table_field again public so it can be used
  in sql_show.cc
  - make created and modified ulonglong, because they should be such
  - make public evex_open_event_table so it can be used in sql_show.cc
sql/event_executor.cc:
  - cosmetics
sql/event_priv.h:
  - moved enum evex_table_field and evex_open_event_table()
    to event.h (made them therefore public)
sql/event_timed.cc:
  - in event_timed::init_definer() always fill this.definer with
    the concatenated value of definer_user@definer_host. Makes
    later the work easier.
  - pass around the definer wherever is needed for searching 
    (new prototype of evex_db_find_evex_aux)
sql/mysqld.cc:
  - add counter for SHOW EVENTS
sql/sql_lex.h:
  - register SHOW EVENTS as command
sql/sql_parse.cc:
  - handle SCH_EVENTS (I_S.EVENTS like SCH_TRIGGERS)
  - make additional check in case of SHOW EVENTS (check for EVENT on
    the current database. if it is null check_access() gives appropriate
    message back.
sql/sql_show.cc:
  - add INFORMATION_SCHEMA.EVENTS and SHOW EVENTS
  - I_S.EVENTS.SQL_MODE is NULL for now -> not implemented. Trudy
    asked to be added so bug #16642 can be completely closed. There
    is another bug report which will fix the lack of storage of
    SQL_MODE during event creation.
sql/sql_yacc.yy:
  - always call event_timed::init_definer() when CREATE/ALTER/DROP
    EVENT but not when just compiling the body of the event because
    in this case this operation is not needed, it takes memory and
    CPU time and at the end the result is not used. event_timed::definer
    is used only on SQLCOM_CREATE/ALTER/DROP_EVENT execution not on
    statement compilation.
  - add SHOW [FULL] EVENTS [FROM db] [LIKE pattern]
    in case of FULL and the user has PROCESS privilege then he will see
    also others' events in the current database, otherwise the output
    is the same as of SHOW EVENTS. Because the events are per DB only
    the events from the current database are shown. pattern is applied
    against event name. FROM db is self explanatory.
sql/table.h:
  add SCH_EVENTS as part of INFORMATION_SCHEMA

VC++Files/client/mysqldump.vcproj:
  Add missing source file.
VC++Files/mysql.sln:
  Fix configuration mismatch.
VC++Files/sql/mysqld.vcproj:
  Enable row-based replication.
  Add missing source files.
scripts/make_win_src_distribution.sh:
  Add copying of missing directory.
sql/event.h:
  Fix type conflict only visible on Windows.
sql/event_executor.cc:
  Fix non-portable thread stuff.
sql/event_timed.cc:
  Fix type conflict only visible on Windows.
sql/ha_archive.cc:
  Add cast needed for Windows.
sql/handler.h:
  Fix Windows byte * <-> char * mismatch.
sql/opt_range.cc:
  Fix Windows byte * <-> char * mismatch.
sql/set_var.cc:
  BUG#16811
  Fix Windows compilation by making the cast-away of volatile implicit
  (Windows linker does not like volatile <-> non-volatile mismatch, in
  contrast to Unix)
sql/sql_partition.cc:
  Fix Windows byte * <-> char * mismatch.

Before the interval expression was considered to be in seconds, now it is
just a number and the type of interval is considered.

- this changeset introduces also fix for bug#16432 (Events: error re interval
  misrepresents the facts)
  the code of event_timed::set_interval() was refactored anyway so it is meaningful to
  fix the bug in the same changeset.


include/my_time.h:
  - move enum interval_type to include/my_time.h so it can be used by functions
    in the whole server
sql/event.cc:
  - don't use second_part
  - fix small problem with create event xyz, when xyz exists -> make it error
    instead of warning if create_if_not is false.
sql/event.h:
  pass thd to mark_last_executed() to be able to call thd->end_time()
sql/event_executor.cc:
  - pass thd to event_timed::compute_next_execution_time()
  - a bit more DBUG info in the server log
  - handle error returned by event_timed::compute_next_execution_time()
sql/event_priv.h:
  - define the maximal possible value for interval_value
sql/event_timed.cc:
  - more docs
  - add static get_next_time() which sums a TIME with an interval
  - fix bug #16435 (Weekly events execute every second)
  Before the interval expression was considered to be in seconds, now it is
  just a number and the type of interval is considered.
  - fix for bug#16432 (Events: error re interval misrepresents the facts)
    (return an error if a value is too big or is negative - errmsg changed)
sql/item_timefunc.cc:
  - export get_interval_date()
  - refactor Item_date_add_interval::get_date() and extract the core
    to date_add_interval() in time.cc so it can be reused by the
    scheduler code in event_timed.cc
sql/item_timefunc.h:
  - export get_interval_value() so it can be reused in event_timed.cc in
    function static get_next_time()
  - move enum interval_type to include/my_time.h so it can be used by functions
    in the whole server
sql/mysql_priv.h:
  export the new function date_add_interval() added to time.cc
sql/share/errmsg.txt:
  - change error message to be appropriate as fix for bug#16432
    (Events: error re interval misrepresents the facts)
sql/sql_yacc.yy:
  - change error message to be appropriate as fix for bug#16432
    (Events: error re interval misrepresents the facts)
sql/time.cc:
  extract the core of Item_date_add_interval::get_date()
  to a function per Serg's request. The code can be reused
  to add und substract interval from a date.

fix problem that gcc4 does not like at all


sql/event.h:
  fix problem that gcc4 does not like at all

  remove extra qualification makeing gcc4 barf


sql/event.h:
  remove extra qualification makeing gcc4 barf

(pre-push cleanups removing debugging code)


sql/event.cc:
  - comment
  - fix 80 cols
  - fix a crash when dropping a running event (after it has finished
    its work because the memory got freed in remove_from_cache but the event
    was still running)
sql/event.h:
  - add new method
sql/event_executor.cc:
  - remove printf-s
  - fix 80cols
  - fix message

- improve the stability of the executor
- make create event if not exists work as before


sql/event.cc:
  refactoring:
  - have only 1 routine for comparing TIME structures 
  fix:
  - after previous refactoring IF NOT EXISTS of CREATE EVENT did not work 
    anymore. Now it will work.
sql/event.h:
  update definitions
sql/event_executor.cc:
  - don't load DISABLED events
  - if an event is being disabled because of time restrictions - drop it from the 
    prio queue
  - move dropping to the worker process
sql/event_priv.h:
  - remove unneeded func
sql/share/errmsg.txt:
  fix error message
sql/sql_parse.cc:
  - support 0 rows affected when CREATE EVENT IF NOT EXISTS

- fix one bug found by PeterG, namely bug #51

#there is a major problem currently after removing the specialised DYNAMIC_ARRAY as 
  storage for the events. I have to reintroduce similar storage, this time probably some
  linked list or maybe some API on top of DYNAMIC_ARRAY.


sql/event.cc:
  close the table
sql/event.h:
  change definition
sql/event_executor.cc:
  don't start the thread in advance
sql/event_timed.cc:
  - don't call evex_drop_event
  - quote the name during compilation to make create event `the rain in spain goes into the drain` not fail.

- varchar -> char
- transient_expression -> interval_value
- interval_type -> interval_field


mysql-test/lib/init_db.sql:
  - varchar -> char
  - transient_expression -> interval_value
  - interval_type -> interval_field
scripts/mysql_fix_privilege_tables.sql:
  - varchar -> char
  - transient_expression -> interval_value
  - interval_type -> interval_field
sql/event.h:
  - varchar -> char
  - transient_expression -> interval_value
  - interval_type -> interval_field

QUEUE implementation working now. this should be ready more or less
for testing once the debug output is being cleaned and some things
around DYNAMIC_ARRAY are cleaned
- fix handling in case of errors that lead to crashes, now no more crashes
  in case of table corruption and such.


include/queues.h:
  introduce a safe version of queue_insert that will extend the queue if
  necessary. the auto_extent is passed to the _ex version of init_queue()
mysys/queues.c:
  add init_queue_ex() implementation
  add queue_insert_safe() implementation
sql/event.cc:
  - move mysql_priv.h inclusion to event_priv.h
  - use a priority queue instead of DYNAMIC_ARRAY which is sorted
sql/event.h:
  reorder
sql/event_executor.cc:
  reorder
sql/event_priv.h:
  - reorder a bit
  - add macroses and functions for queue manipulation which stay on top
   of QUEUE (partly implemented for DYNAMIC_ARRAY but will be cleared to be
   only for QUEUE).
sql/event_timed.cc:
  allocate one more byte and zeroterminate, really

- fix a bug introduced with last commit ALTER EVENT a RENAME TO b; failed
- misc


sql/event.cc:
  - rename evex_db_find_routine_aux() to evex_db_find_event_aux() (better name)
  - change parameter order of db_update_event()
  - last bits to handle errors as close as possible to the place they occur
  - fix a bug introduced with last commit: first check for overwriting and event and then
    check whether the original one exists
sql/event.h:
  add a new error code returned by event_timed::compile() in case of 
  error
sql/event_priv.h:
  rename
sql/event_timed.cc:
  - function rename
  - add a bit of doc
sql/share/errmsg.txt:
  - extend an error message so it's more informative
  - add a new error message
sql/sql_parse.cc:
  refactor the cases for CREATE/ALTER/DROP event so use as much common
  code as possible. last bits of error checking unneeded in sql_parse.cc
  thrwon out.

(strip m_ as prefix from member variables' names)


sql/event.cc:
  - change copyright years
  - remove m_ prefix from member variables (I liked m_)
  - reorder parameter in evex_update_event()
sql/event.h:
  - change copyright years
  - remove m_ prefix from member variables
  - declare some member variables as private (were public)
  - delete 0 is valid in C++ therefore don't embrace with if()
sql/event_executor.cc:
  - executor => scheduler in messages
  - fix a bug introduced in last commit -> typo in a mutex name
  - remove m_ prefix from member variables
sql/event_priv.h:
  - change copyright years
sql/event_timed.cc:
  - change copyright years
  - strip m_ as prefix from member variables' names
sql/sql_parse.cc:
  - strip m_ as prefix from member variables' names
sql/sql_yacc.yy:
  - strip m_ as prefix from member variables names

sql/event.cc:
  -my_error() as close as possible to the place where the error
   occurs.
  -a thought how to replicate events
  -use close_thread_tables() in some cases and for others rely on
   this call being done in sql_parse.cc::do_command()
sql/event.h:
  remove redundant defines
sql/event_executor.cc:
  - reenable the compilation again
  - don't backup the open_tables_state, it's not needed
sql/event_timed.cc:
  - inline a bit
  - comment added
sql/mysqld.cc:
  - start mysqld with --event-scheduler=0 by default
sql/share/errmsg.txt:
  3 new messages
sql/sql_parse.cc:
  remove now obsolete error checking - the errors are reported
  as closer as possible to the place where they are detected
sql/sql_yacc.yy:
  add WARNING message. fix a bug that was corrupting 
  thd->client_capabilites ->
  select count(*) from mysql.event
  was reporting : "Unknown table test.event"!!!
  Using temporal variable is nice but IMO quite error-prone.

updated sources


sql/event.cc:
  update
  put some error calls to the places they occur
sql/event.h:
  - change the default (does not work in STRICT mode)
sql/event_executor.cc:
  move mutex initialization to evex_init_mutexes so init_events() can be reused when the
  main thread does not work and set global event_scheduler=1; (this will start the thread)
  The main thread is now visible with show processlist and can be killed.
sql/event_priv.h:
  don't use anymore SP for opening table
sql/event_timed.cc:
  don't use anymore SP routines for opening mysql.event
sql/mysqld.cc:
  shutdown_events() should be maximal at the end of the server because
  it destroys mutexes of EVEX. The call should not be in the main thread.
sql/set_var.cc:
  make sys_var_event_executor subclass sys_var_bool_ptr
  to overload ::update() method - needed to start a
  killed (non-running) evex main thread
sql/set_var.h:
  declare class sys_var_event_executor
sql/share/errmsg.txt:
  2 new messages

- split into several files
- forbid parallel execution (before analyse is done how to make it possible)
  because the same sp_head instance cannot be executed in parallel
- added GPL headers
- changed EVENT_ACL to be per DB variable
- fixed minor problems


mysql-test/lib/init_db.sql:
  WL#1034 updated
  - add Event_priv to mysql.user (update test)
  - add updated mysql.event table struct
scripts/mysql_fix_privilege_tables.sql:
  WL#1034 updated
  add updated mysql.event structure
sql/Makefile.am:
  split event.cc into
  - event.cc (create/alter/drop)
  - event_executor.cc (main and worker threads)
  - event_timed.cc (class event_timed)
  - event_priv.h (some definitions used internally by the module)
sql/event.cc:
  - added GPL header
  - split into few files
  - fixed some issues after code review
  - now using SP routines for opening/traversing/closing tables
    (will be reverted)
sql/event.h:
  - add GPL header
  - remove two methods - inline them in sql_yacc.yy 
  - don't use absolute values for EVEX_ defines but the SP_ equivalents (have to move 100% to SP_
    defines and as later step to not transfer messages upwards in the stack but
    report them at the place they occur)
  - updated reference table definition
  - move default mem_root param from event.cc to the header
sql/mysqld.cc:
  WL#1034
  rename --event-executor to --event-scheduler
  executor sounds a bit scary :)
sql/set_var.cc:
  rename internal variable name from event_executor to event_scheduler
  (ppl won't be scarried anymore :)
sql/share/errmsg.txt:
  omit one %s - not needed
sql/sp_head.cc:
  disable this DBUG_PRINT for a bit. m_next_cached_sp is 0x0 and I get crash here...
sql/sp_head.h:
  remove m_old_cmq, a temporal variable is used in sql_yacc.yy (Serg's idea)
  to keep the previous state.
  $<ulong_val>$ =  ....
  
  YYTHD->client_capabilites != $<ulong_val>4;
  
  (the same is done also for class event_timed)
sql/sql_acl.cc:
  handle pre-5.1.4 table and give the user EVENT_ACL if he had CREATE_ACL
sql/sql_acl.h:
  fix the bitmask
sql/sql_parse.cc:
  - move from EVENT_ACL being global to EVENT_ACL being per DB like
    CREATE_PROC_ACL
  - lex->m_qname dropped, because not needed, fix code therefore
  - add comment that SHOW CREATE EVENT has to be implemented
sql/sql_yacc.yy:
  - use temporal variable of Bison to store a short lived value
  - fix indentation
  - inline 2 class event_timed methods in the parser
sql/tztime.h:
  be more expressive - it's already extern