WL #1034 updates after review

sql/event.cc:
  - fix TODO (remove things already done)
  - check the length of the event's name and body during creation
    and report an error if longer than what can be fit into 
    mysql.event (nothing like non-strict mode here)
  - report to sql_parse.cc and error when open table failed, otherwise send_ok()
    was being called and the error have become an warning.
  - update function documentation a bit
  - evex_db_find_routine_aux returns 0 and not EVEX_OK
sql/event_executor.cc:
  - CS changes to definitions of the main and worker thread routines
  - reorder code a bit to prevent crashes because of reading of
    already freed data -> first wait all events to finish their work,
    namely all worker threads to finish, and then destroy in-memory
    structures
  - more error checking and error reporting at the place of failure.
sql/event_priv.h:
  code simplifying macro
sql/event_timed.cc:
  CS cosmetics

sql/event.cc

@@ -27,8 +27,6 @@
 
  - Use timestamps instead of datetime.
 
- - Don't use SP's functionality for opening and closing of tables
-
  - CREATE EVENT should not go into binary log! Does it now? The SQL statements
    issued by the EVENT are replicated.
    I have an idea how to solve the problem at failover. So the status field
@@ -44,31 +42,16 @@
    ENABLED to DISABLED status change and this is safe for replicating. As well
    an event may be deleted which is also safe for RBR.
 
- - Add a lock and use it for guarding access to events_array dynamic array.
-
- - Add checks everywhere where new instance of THD is created. NULL can be
-    returned and this will crash the server. The server will crash probably
-    later but should not be in this code! Add a global variable, and a lock
-	to guard it, that will specify an error in a worker thread so preventing
-	new threads from being spawned.
-
  - Maybe move all allocations during parsing to evex_mem_root thus saving
     double parsing in evex_create_event!
 
  - If the server is killed (stopping) try to kill executing events..
  
  - What happens if one renames an event in the DB while it is in memory?
-     Or even deleting it?
-
- - created & modified in the table should be UTC?
- 
- - Add a lock to event_timed to serialize execution of an event - do not
-     allow parallel executions. Hmm, however how last_executed is marked
-     then? The call to event_timed::mark_last_executed() must be moved to
-     event_timed::execute()?
- 
+   Or even deleting it?
+  
  - Consider using conditional variable when doing shutdown instead of
-     waiting some time (tries < 5).
+     waiting till all worker threads end.
  - Make event_timed::get_show_create_event() work
  - Add function documentation whenever needed.
  - Add logging to file
@@ -77,7 +60,7 @@ Warning:
  - For now parallel execution is not possible because the same sp_head cannot be
    executed few times!!! There is still no lock attached to particular event.
 
- */
+*/
 
 
 
@@ -216,17 +199,17 @@ TABLE *evex_open_event_table(THD *thd, enum thr_lock_type lock_type)
       table  TABLE object for open mysql.event table.
 
   RETURN VALUE
-    SP_OK           - Routine found
+    0                - Routine found
     SP_KEY_NOT_FOUND- No routine with given name
 */
 
 int
 evex_db_find_routine_aux(THD *thd, const LEX_STRING dbname,
-                       const LEX_STRING rname, TABLE *table)
+                       const LEX_STRING ev_name, TABLE *table)
 {
   byte key[MAX_KEY_LENGTH];	// db, name, optional key length type
   DBUG_ENTER("evex_db_find_routine_aux");
-  DBUG_PRINT("enter", ("name: %.*s", rname.length, rname.str));
+  DBUG_PRINT("enter", ("name: %.*s", ev_name.length, ev_name.str));
 
   /*
     Create key to find row. We have to use field->store() to be able to
@@ -235,16 +218,16 @@ evex_db_find_routine_aux(THD *thd, const LEX_STRING dbname,
     'db' and 'name' and the first key is the primary key over the
     same fields.
   */
-  if (rname.length > table->field[1]->field_length)
-    DBUG_RETURN(SP_KEY_NOT_FOUND);
+  if (ev_name.length > table->field[1]->field_length)
+    DBUG_RETURN(EVEX_KEY_NOT_FOUND);
 
   table->field[0]->store(dbname.str, dbname.length, &my_charset_bin);
-  table->field[1]->store(rname.str, rname.length, &my_charset_bin);
+  table->field[1]->store(ev_name.str, ev_name.length, &my_charset_bin);
   key_copy(key, table->record[0], table->key_info, table->key_info->key_length);
 
   if (table->file->index_read_idx(table->record[0], 0, key,
-                                  table->key_info->key_length,HA_READ_KEY_EXACT))
-    DBUG_RETURN(SP_KEY_NOT_FOUND);
+                                 table->key_info->key_length,HA_READ_KEY_EXACT))
+    DBUG_RETURN(EVEX_KEY_NOT_FOUND);
 
   DBUG_RETURN(0);
 }
@@ -394,19 +377,18 @@ db_create_event(THD *thd, event_timed *et)
   
   restore_record(table, s->default_values); // Get default values for fields
 
-/* TODO : Uncomment these and add handling in sql_parse.cc or here
 
-  if (sp->m_name.length > table->field[MYSQL_PROC_FIELD_NAME]->field_length)
+  if (et->m_name.length > table->field[EVEX_FIELD_NAME]->field_length)
   {
-    ret= SP_BAD_IDENTIFIER;
-    goto done;
+    my_error(ER_TOO_LONG_IDENT, MYF(0), et->m_name.str);
+    goto err;
   }
-  if (sp->m_body.length > table->field[MYSQL_PROC_FIELD_BODY]->field_length)
+  if (et->m_body.length > table->field[EVEX_FIELD_BODY]->field_length)
   {
-    ret= SP_BODY_TOO_LONG;
-    goto done;
+    my_error(ER_TOO_LONG_BODY, MYF(0), et->m_name.str);
+    goto err;
   }
-*/
+
   if (!(et->m_expr) && !(et->m_execute_at.year))
   {
     DBUG_PRINT("error", ("neither m_expr nor m_execute_as are set!"));
@@ -434,7 +416,8 @@ db_create_event(THD *thd, event_timed *et)
     my_error(ER_EVENT_STORE_FAILED, MYF(0), et->m_name.str);
     goto err;
   }
-  else if (mysql_bin_log.is_open())
+  
+  if (mysql_bin_log.is_open())
   {
     thd->clear_error();
     /* Such a statement can always go directly to binlog, no trans cache */
@@ -472,20 +455,20 @@ static int
 db_update_event(THD *thd, sp_name *name, event_timed *et)
 {
   TABLE *table;
-  int ret;
+  int ret= EVEX_OPEN_TABLE_FAILED;
   DBUG_ENTER("db_update_event");
   DBUG_PRINT("enter", ("name: %.*s", et->m_name.length, et->m_name.str));
   if (name)
     DBUG_PRINT("enter", ("rename to: %.*s", name->m_name.length, name->m_name.str));
 
-  // Todo: Handle in sql_prepare.cc SP_OPEN_TABLE_FAILED
   if (!(table= evex_open_event_table(thd, TL_WRITE)))
   {
     my_error(ER_EVENT_OPEN_TABLE_FAILED, MYF(0));
     goto err;
   }
 
-  if (evex_db_find_routine_aux(thd, et->m_db, et->m_name, table) == SP_KEY_NOT_FOUND)
+  if (EVEX_KEY_NOT_FOUND == evex_db_find_routine_aux(thd, et->m_db, et->m_name,
+                                                     table))
   {
     my_error(ER_EVENT_DOES_NOT_EXIST, MYF(0), et->m_name.str);
     goto err;    
@@ -526,8 +509,21 @@ err:
 
 
 /*
-    Use sp_name for look up, return in **ett if found
+   Looks for a named event in mysql.event and in case of success returns
+   an object will data loaded from the table.
+
+   SYNOPSIS
+     db_find_event()
+       thd      THD
+       name     the name of the event to find
+       ett      event's data if event is found
+       tbl      TABLE object to use when not NULL
+   
+   NOTES
+     1) Use sp_name for look up, return in **ett if found
+     2) tbl is not closed at exit
 */
+
 static int
 db_find_event(THD *thd, sp_name *name, event_timed **ett, TABLE *tbl)
 {
@@ -581,6 +577,22 @@ done:
 }
 
 
+/*
+   Looks for a named event in mysql.event and then loads it from 
+   the table, compiles it and insert it into the cache.
+
+   SYNOPSIS
+     evex_load_and_compile_event()
+       thd       THD
+       spn       the name of the event to alter
+       use_lock  whether to obtain a lock on LOCK_event_arrays or not
+       
+   RETURN VALUE
+       0   - OK
+       < 0 - error (in this case underlying functions call my_error()).
+
+*/
+
 static int
 evex_load_and_compile_event(THD * thd, sp_name *spn, bool use_lock)
 {
@@ -727,7 +739,7 @@ done:
 
 
 /*
-                      Exported functions follow 
+                  -= Exported functions follow =-
 */
 
 /*
@@ -754,15 +766,6 @@ evex_create_event(THD *thd, event_timed *et, uint create_options)
   DBUG_PRINT("enter", ("name: %*s options:%d", et->m_name.length,
                 et->m_name.str, create_options));
 
-/*
-  VOID(pthread_mutex_lock(&LOCK_evex_running));
-  if (!evex_is_running)
-  // TODO: put an warning to the user here.
-  //       Is it needed? (Andrey, 051129)
-  {}  
-  VOID(pthread_mutex_unlock(&LOCK_evex_running));
-*/
-
   if ((ret = db_create_event(thd, et)) == EVEX_WRITE_ROW_FAILED && 
         (create_options & HA_LEX_CREATE_IF_NOT_EXISTS))
   {
@@ -821,13 +824,6 @@ evex_update_event(THD *thd, sp_name *name, event_timed *et)
   DBUG_ENTER("evex_update_event");
   DBUG_PRINT("enter", ("name: %*s", et->m_name.length, et->m_name.str));
 
-/*
-  VOID(pthread_mutex_lock(&LOCK_evex_running));
-  if (!evex_is_running)
-  // put an warning to the user here
-  {}  
-  VOID(pthread_mutex_unlock(&LOCK_evex_running));
-*/
   /*
     db_update_event() opens & closes the table to prevent
     crash later in the code when loading and compiling the new definition
@@ -837,17 +833,8 @@ evex_update_event(THD *thd, sp_name *name, event_timed *et)
 
   VOID(pthread_mutex_lock(&LOCK_evex_running));
   if (!evex_is_running)
-  {
-    // not running - therefore no memory structures
-    VOID(pthread_mutex_unlock(&LOCK_evex_running));
-    goto done;
-  }
-  VOID(pthread_mutex_unlock(&LOCK_evex_running));
+    UNLOCK_MUTEX_AND_BAIL_OUT(LOCK_evex_running, done);
 
-  /*
-    It is possible that 2 (or 1) pass(es) won't find the event in memory.
-    The reason is that DISABLED events are not cached.
-  */
   VOID(pthread_mutex_lock(&LOCK_event_arrays));
   evex_remove_from_cache(&et->m_db, &et->m_name, false);
   if (et->m_status == MYSQL_EVENT_ENABLED)
@@ -860,9 +847,14 @@ evex_update_event(THD *thd, sp_name *name, event_timed *et)
       delete spn;
     }
   VOID(pthread_mutex_unlock(&LOCK_event_arrays));
+  VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
-done:
+  /*
+    It is possible that 2 (or 1) pass(es) won't find the event in memory.
+    The reason is that DISABLED events are not cached.
+  */
 
+done:
   DBUG_RETURN(ret);
 }
 
@@ -882,24 +874,17 @@ int
 evex_drop_event(THD *thd, event_timed *et, bool drop_if_exists)
 {
   TABLE *table;
-  int ret;
+  int ret= EVEX_OPEN_TABLE_FAILED;
   bool opened;
   DBUG_ENTER("evex_drop_event");
 
-/*
-  VOID(pthread_mutex_lock(&LOCK_evex_running));
-  if (!evex_is_running)
-  // put an warning to the user here
-  {}  
-  VOID(pthread_mutex_unlock(&LOCK_evex_running));
-*/
-////
   if (!(table= evex_open_event_table(thd, TL_WRITE)))
-    DBUG_RETURN(SP_OPEN_TABLE_FAILED);
-
-  ret= evex_db_find_routine_aux(thd, et->m_db, et->m_name, table);
+  {
+    my_error(ER_EVENT_OPEN_TABLE_FAILED, MYF(0));
+    goto done;
+  }
 
-  if (ret == EVEX_OK)
+  if (!(ret= evex_db_find_routine_aux(thd, et->m_db, et->m_name, table)))
   {
     if (ret= table->file->delete_row(table->record[0]))
     { 	

sql/event_executor.cc

@@ -21,7 +21,7 @@
 
 #define DBUG_FAULTY_THR2
 
-static uint workers_count;
+extern  ulong thread_created;
 
 
 pthread_mutex_t LOCK_event_arrays,
@@ -33,10 +33,8 @@ bool evex_is_running= false;
 
 ulong opt_event_executor;
 my_bool event_executor_running_global_var= false;
-
-extern ulong thread_created;
-
 static my_bool evex_mutexes_initted= false;
+static uint workers_count;
 
 static int
 evex_load_events_from_db(THD *thd);
@@ -48,8 +46,11 @@ evex_load_events_from_db(THD *thd);
                the main thread or not.
 */
 
-pthread_handler_t event_executor_worker(void *arg);
-pthread_handler_t event_executor_main(void *arg);
+pthread_handler_t
+event_executor_worker(void *arg);
+
+pthread_handler_t
+event_executor_main(void *arg);
 
 static
 void evex_init_mutexes()
@@ -142,8 +143,8 @@ init_event_thread(THD* thd)
   DBUG_RETURN(0);
 }
 
-
-pthread_handler_t event_executor_main(void *arg)
+pthread_handler_t
+event_executor_main(void *arg)
 {
   THD *thd;			/* needs to be first for thread_stack */
   ulonglong iter_num= 0;
@@ -152,13 +153,10 @@ pthread_handler_t event_executor_main(void *arg)
   DBUG_ENTER("event_executor_main");
   DBUG_PRINT("event_executor_main", ("EVEX thread started"));    
 
-  VOID(pthread_mutex_lock(&LOCK_evex_running));
-  evex_is_running= true;  
-  event_executor_running_global_var= opt_event_executor;
-  VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
   // init memory root
   init_alloc_root(&evex_mem_root, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
+  
 
   // needs to call my_thread_init(), otherwise we get a coredump in DBUG_ stuff
   my_thread_init();
@@ -196,6 +194,15 @@ pthread_handler_t event_executor_main(void *arg)
   VOID(my_init_dynamic_array(&evex_executing_queue, sizeof(event_timed *), 50, 100));
   VOID(pthread_mutex_unlock(&LOCK_event_arrays));  
 
+  /*
+    eventually manifest that we are running, not to crashe because of
+    usage of non-initialized memory structures.
+  */
+  VOID(pthread_mutex_lock(&LOCK_evex_running));
+  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))
    goto err;
 
@@ -208,7 +215,6 @@ pthread_handler_t event_executor_main(void *arg)
     my_ulonglong cnt;
     
     DBUG_PRINT("info", ("EVEX External Loop %d", ++cnt));
-//    sql_print_information("[EVEX] External Loop!");
     thd->proc_info = "Sleeping";
     my_sleep(1000000);// sleep 1s
     if (!event_executor_running_global_var)
@@ -216,16 +222,13 @@ pthread_handler_t event_executor_main(void *arg)
     time(&now);
     my_tz_UTC->gmt_sec_to_TIME(&time_now, now);
 
-	
     VOID(pthread_mutex_lock(&LOCK_event_arrays));
     for (i= 0; (i < evex_executing_queue.elements) && !thd->killed; ++i)
     {
-      event_timed **p_et=dynamic_element(&evex_executing_queue,i,event_timed**);
-      event_timed *et= *p_et;
-//      sql_print_information("[EVEX] External Loop 2!");
-      
+      event_timed *et= *dynamic_element(&evex_executing_queue,i,event_timed**);
+//      printf("%llu\n", TIME_to_ulonglong_datetime(&et->m_execute_at));
       if (!event_executor_running_global_var)
-        break;// soon we will do only continue (see the code a bit above)
+        break;
 
       thd->proc_info = "Iterating";
       THD_CHECK_SENTRY(thd);
@@ -233,7 +236,7 @@ pthread_handler_t event_executor_main(void *arg)
         if this is the first event which is after time_now then no
         more need to iterate over more elements since the array is sorted.
       */ 
-      if (et->m_execute_at.year &&
+      if (et->m_execute_at.year > 1969 &&
           my_time_compare(&time_now, &et->m_execute_at) == -1)
         break;
       
@@ -250,8 +253,7 @@ pthread_handler_t event_executor_main(void *arg)
         if (pthread_create(&th, NULL, event_executor_worker, (void*)et))
         {
           sql_print_error("Problem while trying to create a thread");
-          VOID(pthread_mutex_unlock(&LOCK_event_arrays));
-          goto err; // for now finish execution of the Executor
+          UNLOCK_MUTEX_AND_BAIL_OUT(LOCK_event_arrays, err);
         }
 #else
         event_executor_worker((void *) et);
@@ -272,12 +274,12 @@ pthread_handler_t event_executor_main(void *arg)
     j= 0;
     while (j < i && j < evex_executing_queue.elements)
     {
-      event_timed **p_et= dynamic_element(&evex_executing_queue, j, event_timed**);
-      event_timed *et= *p_et;
+      event_timed *et= *dynamic_element(&evex_executing_queue, j, event_timed**);
       if (et->m_flags & EVENT_EXEC_NO_MORE || et->m_status == MYSQL_EVENT_DISABLED)
       {
         delete_dynamic_element(&evex_executing_queue, j);
-        DBUG_PRINT("", ("DELETING FROM EXECUTION QUEUE [%s.%s]",et->m_db.str, et->m_name.str));
+        DBUG_PRINT("EVEX main thread", ("DELETING FROM EXECUTION QUEUE [%s.%s]", 
+                                         et->m_db.str, et->m_name.str));
         // nulling the position, will delete later
         if (et->m_dropped)
         {
@@ -301,29 +303,44 @@ pthread_handler_t event_executor_main(void *arg)
                                  );
 
     VOID(pthread_mutex_unlock(&LOCK_event_arrays));
-  }// while (!thd->killed)
+  }
 
 err:
+  // First manifest that this thread does not work and then destroy
   VOID(pthread_mutex_lock(&LOCK_evex_running));
   evex_is_running= false;  
   VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
   sql_print_information("Event executor stopping");
-  // LEX_STRINGs reside in the memory root and will be destroyed with it.
-  // Hence no need of delete but only freeing of SP
-  for (i=0; i < events_array.elements; ++i)
-  {
-    event_timed *et= dynamic_element(&events_array, i, event_timed*);
-    et->free_sp();
-  }
-  // TODO Andrey: USE lock here!
+
+  /*
+    TODO: A better will be with a conditional variable
+  */
+  /* 
+    Read workers_count without lock, no need for locking.
+    In the worst case we have to wait 1sec more.
+  */
+  while (workers_count)
+    my_sleep(1000000);// 1s
+
+  /*
+    LEX_STRINGs reside in the memory root and will be destroyed with it.
+    Hence no need of delete but only freeing of SP
+  */
+  for (i= 0; i < events_array.elements; ++i)
+    dynamic_element(&events_array, i, event_timed*)->free_sp();
+
+  VOID(pthread_mutex_lock(&LOCK_event_arrays));
+  // No need to use lock here if EVEX is not running but anyway
   delete_dynamic(&evex_executing_queue);
   delete_dynamic(&events_array);
+  VOID(pthread_mutex_unlock(&LOCK_evex_running));
   
   thd->proc_info = "Clearing";
   DBUG_ASSERT(thd->net.buff != 0);
   net_end(&thd->net); // destructor will not free it, because we are weird
   THD_CHECK_SENTRY(thd);
+
   pthread_mutex_lock(&LOCK_thread_count);
   thread_count--;
   thread_running--;
@@ -331,28 +348,6 @@ err:
   delete thd;
   pthread_mutex_unlock(&LOCK_thread_count);
 
-  /*
-    sleeping some time may help not crash the server. sleeping
-    is done to wait for spawned threads to finish.
-    
-    TODO: A better will be with a conditional variable
-  */
-  {
-    uint tries= 0;
-    while (tries++ < 5)
-    {
-      VOID(pthread_mutex_lock(&LOCK_workers_count));
-      if (!workers_count)
-      {
-        VOID(pthread_mutex_unlock(&LOCK_workers_count));
-        break;
-      }  
-      VOID(pthread_mutex_unlock(&LOCK_workers_count));
-      DBUG_PRINT("info", ("Sleep %d", tries));
-      my_sleep(1000000 * tries);// 1s
-    }
-    DBUG_PRINT("info", ("Maybe now it is ok to kill the thread and evex MRoot"));
-  }
 
 err_no_thd:
   VOID(pthread_mutex_lock(&LOCK_evex_running));
@@ -362,30 +357,25 @@ err_no_thd:
   free_root(&evex_mem_root, MYF(0));
   sql_print_information("Event executor stopped");
 
-//  shutdown_events();
-
   my_thread_end();
   pthread_exit(0);
-  DBUG_RETURN(0);				// Can't return anything here
+  DBUG_RETURN(0);// Can't return anything here
 }
 
 
-pthread_handler_t event_executor_worker(void *event_void)
+pthread_handler_t
+event_executor_worker(void *event_void)
 {
   THD *thd; /* needs to be first for thread_stack */
-  List<Item> empty_item_list;
   event_timed *event = (event_timed *) event_void;
-  MEM_ROOT mem_root;
+  MEM_ROOT worker_mem_root;
 
   DBUG_ENTER("event_executor_worker");
   VOID(pthread_mutex_lock(&LOCK_workers_count));
   ++workers_count;  
   VOID(pthread_mutex_unlock(&LOCK_workers_count));
 
-  init_alloc_root(&mem_root, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
-
-  //we pass this empty list as parameter to the SP_HEAD of the event
-  empty_item_list.empty();
+  init_alloc_root(&worker_mem_root, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
 
   my_thread_init();
 
@@ -395,8 +385,10 @@ pthread_handler_t event_executor_worker(void *event_void)
     goto err_no_thd;
   }
   thd->thread_stack = (char*)&thd; // remember where our stack is
-  thd->mem_root= &mem_root;
+  thd->mem_root= &worker_mem_root;
+
   pthread_detach(pthread_self());
+
   if (init_event_thread(thd))
     goto err;
 
@@ -425,7 +417,7 @@ pthread_handler_t event_executor_worker(void *event_void)
     my_TIME_to_str(&event->m_execute_at, exec_time);
     DBUG_PRINT("info", ("    EVEX EXECUTING event for event %s.%s [EXPR:%d][EXECUTE_AT:%s]", event->m_db.str, event->m_name.str,(int) event->m_expr, exec_time));
     sql_print_information("    EVEX EXECUTING event for event %s.%s [EXPR:%d][EXECUTE_AT:%s]", event->m_db.str, event->m_name.str,(int) event->m_expr, exec_time);
-    ret= event->execute(thd, &mem_root);
+    ret= event->execute(thd, &worker_mem_root);
     sql_print_information("    EVEX EXECUTED event for event %s.%s  [EXPR:%d][EXECUTE_AT:%s]. RetCode=%d", event->m_db.str, event->m_name.str,(int) event->m_expr, exec_time, ret); 
     DBUG_PRINT("info", ("    EVEX EXECUTED event for event %s.%s  [EXPR:%d][EXECUTE_AT:%s]", event->m_db.str, event->m_name.str,(int) event->m_expr, exec_time)); 
   }
@@ -454,8 +446,7 @@ err:
 
 err_no_thd:
 
-  free_root(&mem_root, MYF(0));
-//  sql_print_information("    Worker thread exiting");    
+  free_root(&worker_mem_root, MYF(0));
   
   VOID(pthread_mutex_lock(&LOCK_workers_count));
   --workers_count;  
@@ -496,29 +487,38 @@ evex_load_events_from_db(THD *thd)
     }
     DBUG_PRINT("evex_load_events_from_db", ("Loading event from row."));
     
-    if (et->load_from_row(&evex_mem_root, table))
-      //error loading!
-      continue;
+    if ((ret= et->load_from_row(&evex_mem_root, table)))
+    {
+      sql_print_error("Error while loading from mysql.event. "
+                      "Table probably corrupted");
+      goto end;
+    }
     
     DBUG_PRINT("evex_load_events_from_db",
             ("Event %s loaded from row. Time to compile", et->m_name.str));
     
-    if (et->compile(thd, &evex_mem_root))
-      //problem during compile
-      continue;
+    if ((ret= et->compile(thd, &evex_mem_root)))
+    {
+      sql_print_error("Error while compiling %s.%s. Aborting load.",
+                      et->m_db.str, et->m_name.str);
+      goto end;
+    }
     // let's find when to be executed  
     et->compute_next_execution_time();
     
     DBUG_PRINT("evex_load_events_from_db",
                 ("Adding %s to the executor list.", et->m_name.str));
     VOID(push_dynamic(&events_array,(gptr) et));
-    // we always add at the end so the number of elements - 1 is the place
-    // in the buffer
+    /*
+      We always add at the end so the number of elements - 1 is the place
+      in the buffer.
+      DYNAMIC_ARRAY copies the object bit by bit so we have a hollow copy
+      in event_array. We don't need the original therefore we delete it.
+    */
     et_copy= dynamic_element(&events_array, events_array.elements - 1,
-                    event_timed*);
+                             event_timed*);
     VOID(push_dynamic(&evex_executing_queue,(gptr) &et_copy));
     et->m_free_sphead_on_delete= false;
-    DBUG_PRINT("info", (""));
     delete et; 
   }
   end_read_record(&read_record_info);
@@ -536,8 +536,7 @@ evex_load_events_from_db(THD *thd)
 end:
   close_thread_tables(thd);
 
-  DBUG_PRINT("evex_load_events_from_db",
-                    ("Events loaded from DB. Status code %d", ret));
+  DBUG_PRINT("info", ("Finishing with status code %d", ret));
   DBUG_RETURN(ret);
 }
 
@@ -547,7 +546,8 @@ 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) {
+  if ((my_bool) var->save_result.ulong_value && !evex_is_running)
+  {
     VOID(pthread_mutex_unlock(&LOCK_evex_running));
     init_events();
   } else 

sql/event_priv.h

@@ -18,6 +18,9 @@
 #define _EVENT_PRIV_H_
 
 
+#define UNLOCK_MUTEX_AND_BAIL_OUT(__mutex, __label) \
+    { VOID(pthread_mutex_unlock(&__mutex)); goto __label; }
+
 enum
 {
   EVEX_FIELD_DB = 0,

sql/event_timed.cc

@@ -290,7 +290,7 @@ event_timed::init_ends(THD *thd, Item *ends)
   if (ends->fix_fields(thd, &ends))
     DBUG_RETURN(EVEX_PARSE_ERROR);
 
-    // the field was already fixed in init_ends
+  // the field was already fixed in init_ends
   if ((not_used= ends->get_date(&ltime, TIME_NO_ZERO_DATE)))
     DBUG_RETURN(EVEX_BAD_PARAMS);
 
@@ -537,10 +537,19 @@ event_timed::compute_next_execution_time()
   my_tz_UTC->gmt_sec_to_TIME(&time_now, now);
 /*
   sql_print_information("[%s.%s]", m_db.str, m_name.str);
-  sql_print_information("time_now : [%d-%d-%d %d:%d:%d ]", time_now.year, time_now.month, time_now.day, time_now.hour, time_now.minute, time_now.second);
-  sql_print_information("m_starts : [%d-%d-%d %d:%d:%d ]", m_starts.year, m_starts.month, m_starts.day, m_starts.hour, m_starts.minute, m_starts.second);
-  sql_print_information("m_ends   : [%d-%d-%d %d:%d:%d ]", m_ends.year, m_ends.month, m_ends.day, m_ends.hour, m_ends.minute, m_ends.second);
-  sql_print_information("m_last_ex: [%d-%d-%d %d:%d:%d ]", m_last_executed.year, m_last_executed.month, m_last_executed.day, m_last_executed.hour, m_last_executed.minute, m_last_executed.second);
+  sql_print_information("time_now : [%d-%d-%d %d:%d:%d ]", 
+                         time_now.year, time_now.month, time_now.day,
+                         time_now.hour, time_now.minute, time_now.second);
+  sql_print_information("m_starts : [%d-%d-%d %d:%d:%d ]", m_starts.year,
+                        m_starts.month, m_starts.day, m_starts.hour,
+                        m_starts.minute, m_starts.second);
+  sql_print_information("m_ends   : [%d-%d-%d %d:%d:%d ]", m_ends.year,
+                        m_ends.month, m_ends.day, m_ends.hour,
+                        m_ends.minute, m_ends.second);
+  sql_print_information("m_last_ex: [%d-%d-%d %d:%d:%d ]", m_last_executed.year,
+                        m_last_executed.month, m_last_executed.day,
+                        m_last_executed.hour, m_last_executed.minute,
+                        m_last_executed.second);
 */
   //if time_now is after m_ends don't execute anymore
   if (m_ends.year && (tmp= my_time_compare(&m_ends, &time_now)) == -1)
@@ -702,7 +711,6 @@ event_timed::mark_last_executed()
 bool
 event_timed::drop(THD *thd)
 {
-
   return (bool) evex_drop_event(thd, this, false);
 }