A fix for multi-table delete with tables optimised away.

Still not able to make a proper test case as this crashes on files 
where key and data pointers are 4 bytes each. Possibly a proper 
test case would require myisampack.


sql/sql_lex.cc:
  Just in case ...

mysql-test/r/multi_update.result

@@ -66,7 +66,7 @@ select count(*) from t3 where id3;
 count(*)
 0
 drop table t1,t2,t3;
-create table t1(id1 int not null auto_increment primary key, t varchar(100));
-create table t2(id2 int not null, t varchar(100), index(id2));
-delete t1, t2  from t2,t1 where t1.id1 = t2.id2 and t1.id1 > 100;
+create table t1(id1 int not null  primary key, t varchar(100)) pack_keys = 1;
+create table t2(id2 int not null, t varchar(100), index(id2)) pack_keys = 1;
+delete t1  from t1,t2 where t1.id1 = t2.id2 and t1.id1 > 500;
 drop table t1,t2;

mysql-test/t/multi_update.test

@@ -62,14 +62,14 @@ select count(*) from t2 where id2;
 select count(*) from t3 where id3;
 
 drop table t1,t2,t3;
-create table t1(id1 int not null auto_increment primary key, t varchar(100));
-create table t2(id2 int not null, t varchar(100), index(id2));
+create table t1(id1 int not null  primary key, t varchar(100)) pack_keys = 1;
+create table t2(id2 int not null, t varchar(100), index(id2)) pack_keys = 1;
 disable_query_log;
 let $1 = 1000;
 while ($1)
  {
   let $2 = 5;
-  eval insert into t1(t) values ('aaaaaaaaaaaaaaaaaaaa'); 
+  eval insert into t1 values ($1,'aaaaaaaaaaaaaaaaaaaa'); 
   while ($2)
    {
      eval insert into t2(id2,t) values ($1,'bbbbbbbbbbbbbbbbb'); 
@@ -78,5 +78,5 @@ while ($1)
   dec $1;
  }
 enable_query_log;
-delete t1, t2  from t2,t1 where t1.id1 = t2.id2 and t1.id1 > 100;
+delete t1  from t1,t2 where t1.id1 = t2.id2 and t1.id1 > 500;
 drop table t1,t2;

sql/sql_delete.cc

@@ -273,11 +273,11 @@ multi_delete::initialize_tables(JOIN *join)
     if (tab->table->map & tables_to_delete_from)
     {
       /* We are going to delete from this table */
-      walk->table=tab->table;
+      TABLE *tbl=walk->table=tab->table;
+      tbl->no_keyread=1;
+      tbl->used_keys=0;
       walk=walk->next;
-      if (tab == join->join_tab)
-	tab->table->no_keyread=1;
-      if (!not_trans_safe && !tab->table->file->has_transactions())
+      if (!not_trans_safe && !tbl->file->has_transactions())
 	not_trans_safe=true;
     }
   }

sql/sql_lex.cc

@@ -151,6 +151,7 @@ LEX *lex_start(THD *thd, uchar *buf,uint length)
   lex->yacc_yyss=lex->yacc_yyvs=0;
   lex->ignore_space=test(thd->sql_mode & MODE_IGNORE_SPACE);
   lex->slave_thd_opt=0;
+  lex->sql_command=SQLCOM_END;
   bzero(&lex->mi,sizeof(lex->mi));
   return lex;
 }

sql/sql_parse.cc

@@ -1960,7 +1960,11 @@ mysql_execute_command(void)
       }
       auxi->lock_type=walk->lock_type=TL_WRITE;
       auxi->table= (TABLE *) walk;		// Remember corresponding table
-      (void)add_item_to_list(new Item_field(auxi->db,auxi->real_name,"*"));
+    }
+    if (add_item_to_list(new Item_null()))
+    {
+      res = -1;
+      break;
     }
     tables->grant.want_privilege=(SELECT_ACL & ~tables->grant.privilege);
     thd->proc_info="init";