Table definition cache, part 2

The table opening process now works the following way:
- Create common TABLE_SHARE object
- Read the .frm file and unpack it into the TABLE_SHARE object
- Create a TABLE object based on the information in the TABLE_SHARE
  object and open a handler to the table object

Other noteworthy changes:
- In TABLE_SHARE the most common strings are now LEX_STRING's
- Better error message when table is not found
- Variable table_cache is now renamed 'table_open_cache'
- New variable 'table_definition_cache' that is the number of table defintions that will be cached
- strxnmov() calls are now fixed to avoid overflows
- strxnmov() will now always add one end \0 to result
- engine objects are now created with a TABLE_SHARE object instead of a TABLE object.
- After creating a field object one must call field->init(table) before using it

- For a busy system this change will give you:
 - Less memory usage for table object
 - Faster opening of tables (if it's has been in use or is in table definition cache)
 - Allow you to cache many table definitions objects
 - Faster drop of table

1 files changed, 2 insertions, 2 deletions

diff --git a/sql/sql_derived.cc b/sql/sql_derived.cc
index e1817985cbd..5a9871c07c5 100644
--- a/sql/sql_derived.cc
+++ b/sql/sql_derived.cc
@@ -179,8 +179,8 @@ exit:
       }
       orig_table_list->derived_result= derived_result;
       orig_table_list->table= table;
-      orig_table_list->table_name= (char*) table->s->table_name;
-      orig_table_list->table_name_length= strlen((char*)table->s->table_name);
+      orig_table_list->table_name=        table->s->table_name.str;
+      orig_table_list->table_name_length= table->s->table_name.length;
       table->derived_select_number= first_select->select_number;
       table->s->tmp_table= TMP_TABLE;
 #ifndef NO_EMBEDDED_ACCESS_CHECKS