Manual-merge of patch for bug#12546938 from mysql-5.1->mysql-5.5

mysql-test/r/events_bugs.result

@@ -535,6 +535,7 @@ DROP EVENT e3;
 DROP EVENT e2;
 DROP EVENT e1;
 SET TIME_ZONE=@save_time_zone;
+SET TIMESTAMP=DEFAULT;
 drop event if exists new_event;
 CREATE EVENT new_event ON SCHEDULE EVERY 0 SECOND DO SELECT 1;
 ERROR HY000: INTERVAL is either not positive or too big
@@ -756,6 +757,45 @@ SHOW EVENTS;
 Db	Name	Definer	Time zone	Type	Execute at	Interval value	Interval field	Starts	Ends	Status	Originator	character_set_client	collation_connection	Database Collation
 DROP DATABASE event_test1;
 DROP DATABASE event_test12;
+#
+# Bug#12546938 (formerly known as bug#61005):
+# CREATE IF NOT EXIST EVENT WILL CREATE MULTIPLE RUNNING EVENTS
+#
+USE events_test;
+SET GLOBAL event_scheduler = ON;
+DROP TABLE IF EXISTS table_bug12546938;
+DROP EVENT IF EXISTS event_Bug12546938;
+CREATE TABLE table_bug12546938 (i INT);
+# Create an event which will be executed with a small delay
+# and won't be automatically dropped after that.
+CREATE EVENT event_Bug12546938
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 SECOND ON COMPLETION PRESERVE
+ENABLE DO
+BEGIN 
+INSERT INTO table_bug12546938 VALUES(1);
+END
+|
+# Now try to create the same event using CREATE EVENT IF NOT EXISTS.
+# A warning should be emitted. A new event should not be created nor
+# the old event should be re-executed.
+CREATE EVENT IF NOT EXISTS event_bug12546938
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 SECOND ON COMPLETION PRESERVE
+ENABLE DO
+BEGIN
+INSERT INTO table_bug12546938 VALUES (1);
+END
+|
+Warnings:
+Note	1537	Event 'event_bug12546938' already exists
+# Wait until at least one instance of event is executed.
+# Check that only one instance of our event was executed.
+SELECT COUNT(*) FROM table_bug12546938;
+COUNT(*)
+1
+# Clean-up.
+DROP EVENT IF EXISTS event_Bug12546938;
+DROP TABLE table_bug12546938;
+SET GLOBAL EVENT_SCHEDULER = OFF;
 DROP DATABASE events_test;
 SET GLOBAL event_scheduler= 'ON';
 SET @@global.concurrent_insert= @concurrent_insert;

mysql-test/t/events_bugs.test

@@ -857,6 +857,7 @@ DROP EVENT e2;
 DROP EVENT e1;
 
 SET TIME_ZONE=@save_time_zone;
+SET TIMESTAMP=DEFAULT;
 
 #
 # START - BUG#28666 CREATE EVENT ... EVERY 0 SECOND let server crash
@@ -1235,6 +1236,55 @@ SHOW EVENTS;
 DROP DATABASE event_test1;
 DROP DATABASE event_test12;
 
+--echo #
+--echo # Bug#12546938 (formerly known as bug#61005):
+--echo # CREATE IF NOT EXIST EVENT WILL CREATE MULTIPLE RUNNING EVENTS
+--echo #
+USE events_test;
+SET GLOBAL event_scheduler = ON;
+
+--disable_warnings
+DROP TABLE IF EXISTS table_bug12546938;
+DROP EVENT IF EXISTS event_Bug12546938;
+--enable_warnings
+CREATE TABLE table_bug12546938 (i INT); 
+
+delimiter |;
+
+--echo # Create an event which will be executed with a small delay
+--echo # and won't be automatically dropped after that.
+CREATE EVENT event_Bug12546938
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 SECOND ON COMPLETION PRESERVE
+ENABLE DO
+BEGIN 
+  INSERT INTO table_bug12546938 VALUES(1);
+END
+|
+
+--echo # Now try to create the same event using CREATE EVENT IF NOT EXISTS.
+--echo # A warning should be emitted. A new event should not be created nor
+--echo # the old event should be re-executed.
+CREATE EVENT IF NOT EXISTS event_bug12546938
+ON SCHEDULE AT CURRENT_TIMESTAMP + INTERVAL 1 SECOND ON COMPLETION PRESERVE
+ENABLE DO
+BEGIN
+  INSERT INTO table_bug12546938 VALUES (1);
+END
+|
+
+delimiter ;|
+
+--echo # Wait until at least one instance of event is executed.
+let $wait_condition= SELECT COUNT(*) FROM table_bug12546938;
+--source include/wait_condition.inc
+
+--echo # Check that only one instance of our event was executed.
+SELECT COUNT(*) FROM table_bug12546938;
+
+--echo # Clean-up.
+DROP EVENT IF EXISTS event_Bug12546938;
+DROP TABLE table_bug12546938;
+SET GLOBAL EVENT_SCHEDULER = OFF;
 
 ###########################################################################
 #

sql/event_db_repository.cc

@@ -620,18 +620,21 @@ Event_db_repository::open_event_table(THD *thd, enum thr_lock_type lock_type,
   only creates a record on disk.
   @pre The thread handle has no open tables.
 
-  @param[in,out] thd           THD
-  @param[in]     parse_data    Parsed event definition
-  @param[in]     create_if_not TRUE if IF NOT EXISTS clause was provided
-                               to CREATE EVENT statement
-
+  @param[in,out] thd                   THD
+  @param[in]     parse_data            Parsed event definition
+  @param[in]     create_if_not         TRUE if IF NOT EXISTS clause was provided
+                                       to CREATE EVENT statement
+  @param[out]    event_already_exists  When method is completed successfully
+                                       set to true if event already exists else
+                                       set to false
   @retval FALSE  success
   @retval TRUE   error
 */
 
 bool
 Event_db_repository::create_event(THD *thd, Event_parse_data *parse_data,
-                                  my_bool create_if_not)
+                                  bool create_if_not,
+                                  bool *event_already_exists)
 {
   int ret= 1;
   TABLE *table= NULL;
@@ -663,6 +666,7 @@ Event_db_repository::create_event(THD *thd, Event_parse_data *parse_data,
   {
     if (create_if_not)
     {
+      *event_already_exists= true;
       push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_NOTE,
                           ER_EVENT_ALREADY_EXISTS, ER(ER_EVENT_ALREADY_EXISTS),
                           parse_data->name.str);
@@ -670,8 +674,10 @@ Event_db_repository::create_event(THD *thd, Event_parse_data *parse_data,
     }
     else
       my_error(ER_EVENT_ALREADY_EXISTS, MYF(0), parse_data->name.str);
+
     goto end;
-  }
+  } else
+    *event_already_exists= false;
 
   DBUG_PRINT("info", ("non-existent, go forward"));
 

sql/event_db_repository.h

@@ -73,7 +73,8 @@ public:
   Event_db_repository(){}
 
   bool
-  create_event(THD *thd, Event_parse_data *parse_data, my_bool create_if_not);
+  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,

sql/events.cc

@@ -284,6 +284,7 @@ create_query_string(THD *thd, String *buf)
   return 0;
 }
 
+
 /**
   Create a new event.
 
@@ -304,8 +305,8 @@ bool
 Events::create_event(THD *thd, Event_parse_data *parse_data,
                      bool if_not_exists)
 {
-  int ret;
-  bool save_binlog_row_based;
+  bool ret;
+  bool save_binlog_row_based, event_already_exists;
   DBUG_ENTER("Events::create_event");
 
   if (check_if_system_tables_error())
@@ -345,28 +346,32 @@ Events::create_event(THD *thd, Event_parse_data *parse_data,
     DBUG_RETURN(TRUE);
 
   /* On error conditions my_error() is called so no need to handle here */
-  if (!(ret= db_repository->create_event(thd, parse_data, if_not_exists)))
+  if (!(ret= db_repository->create_event(thd, parse_data, if_not_exists,
+                                         &event_already_exists)))
   {
     Event_queue_element *new_element;
     bool dropped= 0;
 
-    if (!(new_element= new Event_queue_element()))
-      ret= TRUE;                                // OOM
-    else if ((ret= db_repository->load_named_event(thd, parse_data->dbname,
-                                                   parse_data->name,
-                                                   new_element)))
+    if (!event_already_exists)
     {
-      if (!db_repository->drop_event(thd, parse_data->dbname, parse_data->name,
-                                     TRUE))
-        dropped= 1;
-      delete new_element;
-    }
-    else
-    {
-      /* TODO: do not ignore the out parameter and a possible OOM error! */
-      bool created;
-      if (event_queue)
-        event_queue->create_event(thd, new_element, &created);
+      if (!(new_element= new Event_queue_element()))
+        ret= TRUE;                                // OOM
+      else if ((ret= db_repository->load_named_event(thd, parse_data->dbname,
+                                                     parse_data->name,
+                                                     new_element)))
+      {
+        if (!db_repository->drop_event(thd, parse_data->dbname, parse_data->name,
+                                       TRUE))
+          dropped= 1;
+        delete new_element;
+      }
+      else
+      {
+        /* TODO: do not ignore the out parameter and a possible OOM error! */
+        bool created;
+        if (event_queue)
+          event_queue->create_event(thd, new_element, &created);
+      }
     }
     /*
       binlog the create event unless it's been successfully dropped
@@ -380,14 +385,14 @@ Events::create_event(THD *thd, Event_parse_data *parse_data,
       {
         sql_print_error("Event Error: An error occurred while creating query string, "
                         "before writing it into binary log.");
-        ret= TRUE;
+        ret= true;
       }
       else
-      {
-        /* If the definer is not set or set to CURRENT_USER, the value of CURRENT_USER
-           will be written into the binary log as the definer for the SQL thread. */
+        /*
+          If the definer is not set or set to CURRENT_USER, the value of CURRENT_USER
+          will be written into the binary log as the definer for the SQL thread.
+        */
         ret= write_bin_log(thd, TRUE, log_query.c_ptr(), log_query.length());
-      }
     }
   }
   /* Restore the state of binlog format */