mariadb/sql/event_db_repository.h
Dmitry Shulga 56a735b782 Fixed bug#12546938 (formerly known as 61005) - CREATE IF NOT EXIST EVENT
will create multiple running events.

A CREATE IF NOT EXIST on an event that existed and was enabled caused
multiple instances of the event to run. Disabling the event didn't  help.
If the event was  dropped, the event stopped running, but when created
again, multiple instances of the event were still running. The only way
to get out of this situation was  to restart the server.

The problem was that Event_db_repository::create_event() didn't return
enough information to discriminate between situation when event didn't
exist and was created and when event did exist and was not created
(but a warning was emitted). As result in the latter case event
was added to in-memory queue of events second time. And this led to
unwarranted multiple executions of the same event.

The solution is to add out-parameter to Event_db_repository::create_event()
method which will signal that event was not created because it already
exists and so it should not be added to the in-memory queue.


mysql-test/r/events_bugs.result:
  Added results for test for Bug#12546938.
mysql-test/t/events_bugs.test:
  Added test for Bug#12546938.
sql/event_db_repository.cc:
  Event_db_repository::create_event was modified: set newly added out-parameter
  event_already_exists to true value if event wasn't created because event
  already existed and IF NOT EXIST clause was present.
sql/event_db_repository.h:
  Added out-parameter 'event_already_exists' to create_event() method.
sql/events.cc:
  Events::create_event was modified: insert new element into
  event queue only if event was actually created.
2011-05-27 16:23:08 +07:00

132 lines
3.6 KiB
C++

#ifndef _EVENT_DB_REPOSITORY_H_
#define _EVENT_DB_REPOSITORY_H_
/* Copyright (C) 2004-2006 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/**
@addtogroup Event_Scheduler
@{
@file event_db_repository.h
Data Dictionary related operations of Event Scheduler.
This is a private header file of Events module. Please do not include it
directly. All public declarations of Events module should be stored in
events.h and event_data_objects.h.
*/
enum enum_events_table_field
{
ET_FIELD_DB = 0,
ET_FIELD_NAME,
ET_FIELD_BODY,
ET_FIELD_DEFINER,
ET_FIELD_EXECUTE_AT,
ET_FIELD_INTERVAL_EXPR,
ET_FIELD_TRANSIENT_INTERVAL,
ET_FIELD_CREATED,
ET_FIELD_MODIFIED,
ET_FIELD_LAST_EXECUTED,
ET_FIELD_STARTS,
ET_FIELD_ENDS,
ET_FIELD_STATUS,
ET_FIELD_ON_COMPLETION,
ET_FIELD_SQL_MODE,
ET_FIELD_COMMENT,
ET_FIELD_ORIGINATOR,
ET_FIELD_TIME_ZONE,
ET_FIELD_CHARACTER_SET_CLIENT,
ET_FIELD_COLLATION_CONNECTION,
ET_FIELD_DB_COLLATION,
ET_FIELD_BODY_UTF8,
ET_FIELD_COUNT /* a cool trick to count the number of fields :) */
};
int
events_table_index_read_for_db(THD *thd, TABLE *schema_table,
TABLE *event_table);
int
events_table_scan_all(THD *thd, TABLE *schema_table, TABLE *event_table);
class Event_basic;
class Event_parse_data;
class Event_db_repository
{
public:
Event_db_repository(){}
bool
create_event(THD *thd, Event_parse_data *parse_data, bool create_if_not,
bool *event_already_exists);
bool
update_event(THD *thd, Event_parse_data *parse_data, LEX_STRING *new_dbname,
LEX_STRING *new_name);
bool
drop_event(THD *thd, LEX_STRING db, LEX_STRING name, bool drop_if_exists);
void
drop_schema_events(THD *thd, LEX_STRING schema);
bool
find_named_event(LEX_STRING db, LEX_STRING name, TABLE *table);
bool
load_named_event(THD *thd, LEX_STRING dbname, LEX_STRING name, Event_basic *et);
bool
open_event_table(THD *thd, enum thr_lock_type lock_type, TABLE **table);
bool
fill_schema_events(THD *thd, TABLE_LIST *tables, const char *db);
bool
update_timing_fields_for_event(THD *thd,
LEX_STRING event_db_name,
LEX_STRING event_name,
bool update_last_executed,
my_time_t last_executed,
bool update_status,
ulonglong status);
public:
static bool
check_system_tables(THD *thd);
private:
void
drop_events_by_field(THD *thd, enum enum_events_table_field field,
LEX_STRING field_value);
bool
index_read_for_db_for_i_s(THD *thd, TABLE *schema_table, TABLE *event_table,
const char *db);
bool
table_scan_all_for_i_s(THD *thd, TABLE *schema_table, TABLE *event_table);
private:
/* Prevent use of these */
Event_db_repository(const Event_db_repository &);
void operator=(Event_db_repository &);
};
/**
@} (End of group Event_Scheduler)
*/
#endif /* _EVENT_DB_REPOSITORY_H_ */