WL#1034 (update)

- fixed silly bug, the main thread restarted but did not execute events,
  Quite currious why many calls to pthread_mutex_init() do not lead to abort()


sql/event.cc:
  - remove mysql_event_table_exists
  - fix possible crash when table is 0x0
sql/event_executor.cc:
  - make event_executor_running_global_var volatile
  - fix erroneous reinitilization of a mutex, why did it not crash in debug mode?
    why pthread_mutex_init() does not abort() in case the mutex was not deinitted
    beforehand?
  - first initialization of event_executor_running_global_var inside init_mutexes()
  - remove debug if()
sql/event_priv.h:
  - remove unneeded definitions
sql/event_timed.cc:
  make backup and then restore the open table state of thd

sql/event.cc

@@ -64,14 +64,10 @@ Warning:
 */
 
 
-
-
-bool mysql_event_table_exists= 1;
 QUEUE EVEX_EQ_NAME;
 MEM_ROOT evex_mem_root;
 
 
-
 void
 evex_queue_init(EVEX_QUEUE_TYPE *queue)
 {
@@ -175,7 +171,6 @@ event_timed_compare(event_timed **a, event_timed **b)
   else
     return 0;
   
-//  return my_time_compare(&(*a)->execute_at, &(*b)->execute_at);
 }
 
 
@@ -204,23 +199,13 @@ TABLE *evex_open_event_table(THD *thd, enum thr_lock_type lock_type)
   bool not_used;
   DBUG_ENTER("open_proc_table");
 
-  /*
-    Speed up things if the table doesn't exists. *table_exists
-    is set when we create or read stored procedure or on flush privileges.
-  */
-  if (!mysql_event_table_exists)
-    DBUG_RETURN(0);
-
   bzero((char*) &tables, sizeof(tables));
   tables.db= (char*) "mysql";
   tables.table_name= tables.alias= (char*) "event";
   tables.lock_type= lock_type;
 
   if (simple_open_n_lock_tables(thd, &tables))
-  {
-    mysql_event_table_exists= 0;
     DBUG_RETURN(0);
-  }
 
   DBUG_RETURN(tables.table);
 }
@@ -638,7 +623,7 @@ done:
     et= 0;
   }
   // don't close the table if we haven't opened it ourselves
-  if (!tbl)
+  if (!tbl && table)
     close_thread_tables(thd);
   *ett= et;
   DBUG_RETURN(ret);
@@ -745,9 +730,7 @@ done:
 }
 
 
-/*
-                  -= Exported functions follow =-
-*/
+
 
 /*
    The function exported to the world for creating of events.

sql/event_executor.cc

@@ -41,7 +41,7 @@ bool evex_is_running= false;
 
 ulonglong evex_main_thread_id= 0;
 ulong opt_event_executor;
-my_bool event_executor_running_global_var= false;
+volatile my_bool event_executor_running_global_var;
 static my_bool evex_mutexes_initted= false;
 static uint workers_count;
 
@@ -65,13 +65,14 @@ static
 void evex_init_mutexes()
 {
   if (evex_mutexes_initted)
-  {
-    evex_mutexes_initted= true;
     return;
-  }
+
+  evex_mutexes_initted= true;
   pthread_mutex_init(&LOCK_event_arrays, MY_MUTEX_INIT_FAST);
   pthread_mutex_init(&LOCK_workers_count, MY_MUTEX_INIT_FAST);
   pthread_mutex_init(&LOCK_evex_running, MY_MUTEX_INIT_FAST);
+
+  event_executor_running_global_var= opt_event_executor;
 }
 
 
@@ -88,7 +89,6 @@ init_events()
 
   VOID(pthread_mutex_lock(&LOCK_evex_running));
   evex_is_running= false;  
-  event_executor_running_global_var= false;
   VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
 #ifndef DBUG_FAULTY_THR
@@ -206,7 +206,6 @@ event_executor_main(void *arg)
   evex_queue_init(&EVEX_EQ_NAME);
   VOID(pthread_mutex_unlock(&LOCK_event_arrays));  
   evex_is_running= true;  
-  event_executor_running_global_var= opt_event_executor;
   VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
   if (evex_load_events_from_db(thd))
@@ -224,7 +223,7 @@ event_executor_main(void *arg)
     
     cnt++;
     DBUG_PRINT("info", ("EVEX External Loop %d", cnt));
-    if (cnt > 1000) continue;
+
     thd->proc_info = "Sleeping";
     if (!evex_queue_num_elements(EVEX_EQ_NAME) ||
         !event_executor_running_global_var)
@@ -573,18 +572,17 @@ end:
 }
 
 
-
 bool sys_var_event_executor::update(THD *thd, set_var *var)
 {
   // here start the thread if not running.
   VOID(pthread_mutex_lock(&LOCK_evex_running));
-  if ((my_bool) var->save_result.ulong_value && !evex_is_running)
+  *value= var->save_result.ulong_value;
+  if ((my_bool) *value && !evex_is_running)
   {
     VOID(pthread_mutex_unlock(&LOCK_evex_running));
     init_events();
   } else 
     VOID(pthread_mutex_unlock(&LOCK_evex_running));
-
-  return sys_var_bool_ptr::update(thd, var);
+  return 0;
 }
 

sql/event_priv.h

@@ -88,8 +88,6 @@ evex_queue_init(EVEX_QUEUE_TYPE *queue);
 
 
 extern bool evex_is_running;
-extern bool mysql_event_table_exists;
-//extern DYNAMIC_ARRAY events_array;
 extern MEM_ROOT evex_mem_root;
 extern pthread_mutex_t LOCK_event_arrays,
                        LOCK_workers_count,

sql/event_timed.cc

@@ -725,6 +725,7 @@ bool
 event_timed::update_fields(THD *thd)
 {
   TABLE *table;
+  Open_tables_state backup;
   int ret= 0;
   bool opened;
 
@@ -736,8 +737,14 @@ event_timed::update_fields(THD *thd)
   if (!(status_changed || last_executed_changed))
     goto done;
   
+  thd->reset_n_backup_open_tables_state(&backup);
+
   if (!(table= evex_open_event_table(thd, TL_WRITE)))
-    DBUG_RETURN(SP_OPEN_TABLE_FAILED);
+  {
+    ret= SP_OPEN_TABLE_FAILED;
+    goto done;
+  }
+
 
   if ((ret= evex_db_find_event_aux(thd, dbname, name, table)))
     goto done;
@@ -764,6 +771,7 @@ event_timed::update_fields(THD *thd)
 
 done:
   close_thread_tables(thd);
+  thd->restore_backup_open_tables_state(&backup);
 
   DBUG_RETURN(ret);
 }
@@ -798,7 +806,7 @@ event_timed::get_show_create_event(THD *thd, uint *length)
   *dst= '\0';
  
   *length= len;
-  dst[len]= '\0'; 
+
   sql_print_information("%d %d[%s]", len, dst-ret, ret);
   return ret;
 }