WL#1034 ongoing updates after review

sql/event.cc:
  -my_error() as close as possible to the place where the error
   occurs.
  -a thought how to replicate events
  -use close_thread_tables() in some cases and for others rely on
   this call being done in sql_parse.cc::do_command()
sql/event.h:
  remove redundant defines
sql/event_executor.cc:
  - reenable the compilation again
  - don't backup the open_tables_state, it's not needed
sql/event_timed.cc:
  - inline a bit
  - comment added
sql/mysqld.cc:
  - start mysqld with --event-scheduler=0 by default
sql/share/errmsg.txt:
  3 new messages
sql/sql_parse.cc:
  remove now obsolete error checking - the errors are reported
  as closer as possible to the place where they are detected
sql/sql_yacc.yy:
  add WARNING message. fix a bug that was corrupting 
  thd->client_capabilites ->
  select count(*) from mysql.event
  was reporting : "Unknown table test.event"!!!
  Using temporal variable is nice but IMO quite error-prone.

sql/event.h

@@ -40,17 +40,6 @@ extern ulong opt_event_executor;
 #define EVENT_EXEC_NO_MORE      (1L << 0)
 #define EVENT_NOT_USED          (1L << 1)
 
-#define SP_OK                 0
-#define SP_KEY_NOT_FOUND     -1
-#define SP_OPEN_TABLE_FAILED -2
-#define SP_WRITE_ROW_FAILED  -3
-#define SP_DELETE_ROW_FAILED -4
-#define SP_GET_FIELD_FAILED  -5
-#define SP_PARSE_ERROR       -6
-#define SP_INTERNAL_ERROR    -7
-#define SP_NO_DB_ERROR       -8
-#define SP_BAD_IDENTIFIER    -9
-#define SP_BODY_TOO_LONG    -10
 
 extern ulong opt_event_executor;
 

sql/event_executor.cc

@@ -80,8 +80,6 @@ init_events()
   event_executor_running_global_var= false;
   VOID(pthread_mutex_unlock(&LOCK_evex_running));
 
-  DBUG_RETURN(0);
-/*
 #ifndef DBUG_FAULTY_THR
   //TODO Andrey: Change the error code returned!
   if (pthread_create(&th, NULL, event_executor_main, (void*)NULL))
@@ -91,7 +89,6 @@ init_events()
 #endif
 
   DBUG_RETURN(0);
-*/
 }
 
 
@@ -109,7 +106,6 @@ shutdown_events()
   DBUG_VOID_RETURN;
 }
 
-#ifdef ANDREY_0
 
 static int
 init_event_thread(THD* thd)
@@ -479,13 +475,11 @@ evex_load_events_from_db(THD *thd)
   TABLE *table;
   READ_RECORD read_record_info;
   MYSQL_LOCK *lock;
-  Open_tables_state open_tables_state_backup;
   int ret= -1;
   
   DBUG_ENTER("evex_load_events_from_db");  
 
-  if (!(table= open_proc_type_table_for_read(thd, &open_tables_state_backup,
-                                             "event", &mysql_event_table_exists)))
+  if (!(table= evex_open_event_table(thd, TL_READ)))
     DBUG_RETURN(SP_OPEN_TABLE_FAILED);
 
   VOID(pthread_mutex_lock(&LOCK_event_arrays));
@@ -541,18 +535,16 @@ evex_load_events_from_db(THD *thd)
 
 end:
   close_thread_tables(thd);
-  thd->restore_backup_open_tables_state(&open_tables_state_backup);
 
   DBUG_PRINT("evex_load_events_from_db",
                     ("Events loaded from DB. Status code %d", ret));
   DBUG_RETURN(ret);
 }
 
-#endif
+
 
 bool sys_var_event_executor::update(THD *thd, set_var *var)
 {
-#ifdef ANDREY_0
   // 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) {
@@ -560,7 +552,7 @@ bool sys_var_event_executor::update(THD *thd, set_var *var)
     init_events();
   } else 
     VOID(pthread_mutex_unlock(&LOCK_evex_running));
-#endif  
+
   return sys_var_bool_ptr::update(thd, var);
 }
 

sql/event_timed.cc

@@ -322,10 +322,8 @@ event_timed::init_comment(THD *thd, LEX_STRING *comment)
 {
   DBUG_ENTER("event_timed::init_comment");
 
-  MEM_ROOT *root= thd->mem_root;
-  m_comment.length= comment->length;
-  m_comment.str= strmake_root(root, comment->str, comment->length);
-  DBUG_PRINT("m_comment", ("len=%d",m_comment.length));
+  m_comment.str= strmake_root(thd->mem_root, comment->str,
+                              m_comment.length= comment->length);
 
   DBUG_VOID_RETURN;
 }
@@ -359,6 +357,11 @@ event_timed::init_definer(THD *thd)
  
  SYNOPSIS
    event_timed::load_from_row()
+   
+ REMARKS
+   This method is silent on errors and should behave like that. Callers
+   should handle throwing of error messages. The reason is that the class
+   should not know about how to deal with communication.
 */
 
 int

sql/mysqld.cc

@@ -4810,7 +4810,7 @@ Disable with --skip-bdb (will save memory).",
    0, GET_BOOL, NO_ARG, 0, 0, 0, 0, 0, 0},
   {"event-scheduler", OPT_EVENT_EXECUTOR, "Enable/disable the event scheduler.",
    (gptr*) &opt_event_executor, (gptr*) &opt_event_executor, 0, GET_BOOL, NO_ARG,
-   1/*default*/, 0/*min-value*/, 1/*max-value*/, 0, 0, 0},
+   0/*default*/, 0/*min-value*/, 1/*max-value*/, 0, 0, 0},
   {"exit-info", 'T', "Used for debugging;  Use at your own risk!", 0, 0, 0,
    GET_LONG, OPT_ARG, 0, 0, 0, 0, 0, 0},
   {"external-locking", OPT_USE_LOCKING, "Use system (external) locking.  With this option enabled you can run myisamchk to test (not repair) tables while the MySQL server is running.",

sql/share/errmsg.txt

@@ -5741,3 +5741,9 @@ ER_EVENT_OPEN_TABLE_FAILED
         eng "Failed to open mysql.event"
 ER_EVENT_NEITHER_M_EXPR_NOR_M_AT
         eng "No datetime expression provided"
+ER_EVENT_COL_COUNT_DOESNT_MATCH
+        eng "Column count of %s.%s is wrong. Table probably corrupted"
+ER_EVENT_CANNOT_LOAD_FROM_TABLE
+        eng "Cannot load from mysql.event. Table probably corrupted"
+ER_EVENT_CANNOT_DELETE
+        eng "Failed to delete the event from mysql.event"

sql/sql_parse.cc

@@ -3689,21 +3689,8 @@ mysql_execute_command(THD *thd)
     int result;
     uint create_options= lex->create_info.options;
     res= (result= evex_create_event(thd, lex->et, create_options));
-    switch (result) {
-    case EVEX_OK:
+    if (result == EVEX_OK)
       send_ok(thd, 1);
-      break;
-    case EVEX_WRITE_ROW_FAILED:
-      my_error(ER_EVENT_ALREADY_EXISTS, MYF(0), lex->et->m_name.str);
-      break;
-    case EVEX_NO_DB_ERROR:
-      my_error(ER_BAD_DB_ERROR, MYF(0), lex->et->m_db.str);
-      break;
-    default:
-      //includes EVEX_PARSE_ERROR
-      my_error(ER_EVENT_STORE_FAILED, MYF(0), lex->et->m_name.str);
-      break;
-    }
     /* lex->unit.cleanup() is called outside, no need to call it here */
     delete lex->et;
     lex->et= 0;

sql/sql_yacc.yy

@@ -1312,6 +1312,10 @@ create:
 	    Lex->sql_command = SQLCOM_CREATE_USER;
           }
 	| CREATE EVENT_SYM opt_if_not_exists sp_name
+          /* 
+             BE CAREFUL when you add a new rule to update the block where 
+             YYTHD->client_capabilities is set back to original value
+          */
           {
             LEX *lex=Lex;
 
@@ -1351,12 +1355,19 @@ create:
           DO_SYM ev_sql_stmt
           {
             /*
-              sql_command is set here because some rules in ev_sql_stmt
-              can overwrite it
+              Restore flag if it was cleared above
+              $1 - CREATE
+              $2 - EVENT_SYM
+              $3 - opt_if_not_exists
+              $4 - sp_name
+              $5 - the block above
             */
-            // Restore flag if it was cleared above
             YYTHD->client_capabilities |= $<ulong_num>5;
 
+            /*
+              sql_command is set here because some rules in ev_sql_stmt
+              can overwrite it
+            */
             Lex->sql_command= SQLCOM_CREATE_EVENT;
           }
       ;
@@ -4192,6 +4203,10 @@ alter:
 	  view_list_opt AS view_select view_check_option
 	  {}
 	| ALTER EVENT_SYM sp_name
+          /* 
+             BE CAREFUL when you add a new rule to update the block where 
+             YYTHD->client_capabilities is set back to original value
+          */
           {
             LEX *lex=Lex;
             event_timed *et;
@@ -4233,11 +4248,18 @@ alter:
           ev_comment
           ev_opt_sql_stmt
           {
+            /*
+              $1 - ALTER
+              $2 - EVENT_SYM
+              $3 - sp_name
+              $4 - the block above
+            */
+            YYTHD->client_capabilities |= $<ulong_num>4;
+
             /*
               sql_command is set here because some rules in ev_sql_stmt
               can overwrite it
             */
-            YYTHD->client_capabilities |= $<ulong_num>3;
             Lex->sql_command= SQLCOM_ALTER_EVENT;
           }	  
       ;