There actually were several problems here:
- WRITE-lock is required to load events from the mysql.event table,
but in the read-only mode an ordinary user can not acquire it;
- Security_context::master_access attribute was not properly
initialized in Security_context::init(), which led to differences
in behavior with and without debug configure options.
- if the server failed to load events from mysql.event, it forgot to
close the mysql.event table, that led to the coredump, described
in the bug report.
The patch is to fix all these problems:
- Use the super-user to acquire WRITE-lock on the mysql.even table;
- The WRITE-lock is acquired by the event scheduler in two cases:
- on initial loading of events from the database;
- when an event has been executed, so its attributes should
be updated.
Other cases when WRITE-lock is needed for the mysql.event table
happen under the user account. So, nothing should be changed there
for the read-only mode. The user is able to create/update/drop
an event only if he is a super-user.
- Initialize Security_context::master_access;
- Close the mysql.event table in case something went wrong.
--long-query-time is now given in seconds with microseconds as decimals
--min_examined_row_limit added for slow query log
long_query_time user variable is now double with 6 decimals
Added functions to get time in microseconds
Added faster time() functions for system that has gethrtime() (Solaris)
We now do less time() calls.
Added field->in_read_set() and field->in_write_set() for easier field manipulation by handlers
set_var.cc and my_getopt() can now handle DOUBLE variables.
All time() calls changed to my_time()
my_time() now does retry's if time() call fails.
Added debug function for stopping in mysql_admin_table() when tables are locked
Some trivial function and struct variable renames to avoid merge errors.
Fixed compiler warnings
Initialization of some time variables on windows moved to my_init()
Uninitialized in the constructor member variables were
pointing to nirvana and causing a crash when debug information
of the Event Scheduler was dumped in result to COM_DEBUG
packet sent to the server.
streamline the event worker thread work flow and try to eliminate
possibilities for memory corruptions that might have been
lurking in previous (complicated) code.
This patch:
* removes Event_job_data::compile that was never used
* cleans up Event_job_data::execute to minimize juggling with
thread context and eliminate unneded code paths
* Implements Security_context::change/restore_security_context
to be able to re-use these methods in all stored programs
This is to maybe fix Bug#27733 "Valgrind failures in
remove_table_from_cache".
Review comments applied.
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
BUG#26429: SHOW CREATE EVENT is incorrect for an event that
STARTS NOW()
BUG#26431: Impossible to re-create an event from backup if its
STARTS clause is in the past
WL#3698: Events: execution in local time zone
The problem was that local times specified by the user in AT, STARTS
and ENDS of CREATE EVENT/ALTER EVENT statement were converted to UTC,
and the original time zone was forgotten. This way, event scheduler
couldn't honor Daylight Saving Time shifts, and times shown to the
user were also in UTC. Additionally, CREATE EVENT didn't allow times
in the past, thus preventing straightforward event restoration from
old backups.
This patch reworks event scheduler time computations, performing them
in the time zone associated with the event. Also it allows times to
be in the past.
The patch adds time_zone column to mysql.event table.
NOTE: The patch is almost final, but the bug#9953 should be pushed
first.
This patch implements the idea of the bug report by making Event_queue
unaware of Event_db_repository by making a higher level class - Events,
which is aware of most of all classes, responsible for passing all data
needed for adding/updating/deleting an event to/from the queue.
Introduces few new classes :
- Event_worker_thread
- Event_queue_element_for_exec
- Removed not used variables
- Changed some ulong parameters/variables to ulonglong (possible serious bug)
- Added casts to get rid of safe assignment from longlong to long (and similar)
- Added casts to function parameters
- Fixed signed/unsigned compares
- Added some constructores to structures
- Removed some not portable constructs
Better fix for bug Bug #21428 "skipped 9 bytes from file: socket (3)" on "mysqladmin shutdown"
(Added new parameter to net_clear() to define when we want the communication buffer to be emptied)
Added missing DBUG_RETURN statements (in mysqldump.c)
Added missing enums
Fixed a lot of wrong DBUG_PRINT() statements, some of which could cause crashes
Removed usage of %lld and %p in printf strings as these are not portable or produces different results on different systems.
Remove SHOW SCHEDULER STATUS command and migrate the
information output to `mysqladmin debug` (COM_DEBUG)
SHOW SCHEDULER STATUS was introduced in 5.1.11, provided
some debug information about event scheduler internals and
was enabled only in debug builds.
This patch makes the relationship between Event_scheduler and Event_queue
unidirectional from the former to the latter.
The change is that the conditional on which the scheduler sleeped has been
moved to the Event_queue and the latter does not call anymore
Event_scheduler::queue_changed(), which in turn has be removed.
Cleaned up the code a bit. Fixed few leaks.
This code still does not load events on server startup
from disk. The problem is that there is a need for a THD instance, which
does not exist during server boot. This will be solved soon.
Still Event_timed is used both for the memory queue and for exectution.
This will be changed according to WL#3337 probably in the next commit.
Cut Nr. 8.
All tests pass.
Separated Event_scheduler into Event_queue and Event_scheduler.
Added new Event_scheduler_ng which is the new scheduler and is used
system-wide. Will be moved to the event_scheduler.cc in the future.
Using Event_timed in Event_queue as well as cloned during execution.
Next step is to have Event_worker_data which will be used during execution
and will take ::compile()/::execute() out of Event_timed.
This is the first cut of separating Event_scheduler in two
classes which are more specialized.
Inheritance was used to separate methods and member variables.
Still Event_scheduler is a child of Event_queue. This dependency
will be removed soon.
This cut No 7 should finish the part of fixing the parsing of the events :
- Event_timed is no more used during parsing. Less problems because it has
a mutex. Event_parse_data class is used during parsing. It is suited only
for this purpose. It's pretty lightweight
- Late checking of data from parsing is being performed. This should solve
the problems of nested events in SP or other events (for the situation
of no nested bodies). Before if an ALTER EVENT was in a SP, then when the
SP was compiled, and not executed, the actual init_xxx methods of Event_timed
were called, which is wrong.
- It could be a side effect of using a specialized class, but test events_stress is
now 25% quicker.
Cut No8 will start splitting Event_scheduler into 2 parts, the QUEUE will be moved
to Event_queue.
5th cut, moved DB related code to Event_db_repository and
updated accordingly the remanining code.
Moved change/restore_security_context() to class THD
Removed events_priv.h
Next step is to reorganize create/update_event() and parsing for them.
But probably some other refactoring could be done in the meanwhile.
The changes so far pass the test suite.
Third cut to simplify parsing phase. Now DROP EVENT works.
Overloaded few functions to be able to use either sp_name or pass two LEX_STRINGs
instead of a Event_timed pointer. This is transitional and eventually the old
functions will be removed. For now DROP EVENT also works, does not need anymore
a parsing object (Event_timed) and definer initialization because everyone who
has EVENT_ACL can drop events, and this is checked on execution time in sql_parse.cc
from the security context, as it should be.
Unify method naming -> create/update/drop_event
Move class Event_timed to event_timed.h
class Events is in events.h (renamed from event.h)
The implementation is in events.cc (renamed from event.h)
- 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
