From 9222603a777e4627676cdf17ad82afa459f1e0c2 Mon Sep 17 00:00:00 2001 From: unknown Date: Mon, 29 Jan 2007 20:46:29 +0300 Subject: Fix for bug#22740 Events: Decouple Event_queue from Event_db_repository 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 sql/event_data_objects.cc: Introduced a new class Event_queue_element_for_exec According to Konstantin it should be named Event_name and hold only two LEX_STRINGs but `dropped` is not saved on disk and will require additional logic in Event_worker_thread class, after loading to compute whether the event should be dropped or not. It's easier just to pass this flag around. Removed Event_queue_element::drop(). This method was a source of a race condition. At the place where the event should be dropped we call Events::drop_event() which is the only code-flow for dropping. In addition, because ::drop_event() holds Events::LOCK_metadata there is no source of race conditions. Before this patch dropping from ::drop() wasn't under LOCK_metadata and races were possible. Because Events::open_event_table was removed as a method, provisionally events_event_db_repository was exported from events.cc till a solution is build where Event_queue_element does not access directly mysql.event. sql/event_data_objects.h: New class Event_queue_element_for_exec added which is returned from Event_queue::get_top_if_time() and passed through Event_scheduler to Event_worker_thread. There by using the (db)name Event_job_data is instanciated and executed. Dropped Event_queue_element::drop() thd was moved out of Event_job_data as it is now part of Event_queue_element_for_exec sql/event_queue.cc: Removed dependency of Event_queue on Event_db_repository. The instantiation of Event_job_data was moved to class Event_worker_thread In place is a return of an object of Event_queue_element_for_exec is used later for instantiating Event_job_data. The `dropped` flag of Event_queue_element is passed over Event_queue_element_for_exec to the code in Event_worker_thread. sql/event_queue.h: Removed dependency of Event_queue on Event_db_repository Removed dependency on Event_scheduler sql/event_scheduler.cc: Added class Event_worker_thread, which is used during the execution of an event. It has a static init() method to get a pointer to Event_db_repository to be used for instantiation of Event_job_data object. This object it then executed. sql/event_scheduler.h: Added class Event_worker_thread, which is used during the execution of an event. sql/events.cc: Removed Events::open_event_table() because it was a product of a bad architecture. sql/events.h: Removed friend definition, unneeded. Fixed Events::drop_event() to have the previous signature without bool only_from_disk sql/sql_parse.cc: Fix call --- sql/event_data_objects.h | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'sql/event_data_objects.h') diff --git a/sql/event_data_objects.h b/sql/event_data_objects.h index e00b0b94eaf..4346b0eb5b8 100644 --- a/sql/event_data_objects.h +++ b/sql/event_data_objects.h @@ -27,6 +27,27 @@ class sp_head; class Sql_alloc; +class Event_queue_element_for_exec +{ +public: + Event_queue_element_for_exec(){}; + ~Event_queue_element_for_exec(); + + bool + init(LEX_STRING dbname, LEX_STRING name); + + LEX_STRING dbname; + LEX_STRING name; + bool dropped; + THD *thd; + +private: + /* Prevent use of these */ + Event_queue_element_for_exec(const Event_queue_element_for_exec &); + void operator=(Event_queue_element_for_exec &); +}; + + class Event_basic { protected: @@ -96,9 +117,6 @@ public: bool compute_next_execution_time(); - int - drop(THD *thd); - void mark_last_executed(THD *thd); @@ -160,7 +178,6 @@ public: class Event_job_data : public Event_basic { public: - THD *thd; sp_head *sphead; LEX_STRING body; -- cgit v1.2.1