Improved storage size for Item, Field and some other classes

- Changed order of class fields to remove dead alignment space.
- Changed bool fields in Item to bit fields.
- Used packed enum's for some fields in common classes
- Removed not used Item::rsize.
- Changed some class variables from uint/int to smaller type int's.
- Ensured that field_index is uint16 in all classes and functions. Fixed
  also that we proparly compare with NO_CACHED_FIELD_INDEX when checking
  if variable is not set.
- Removed checking of highest bit of unireg_check (has not been used in
  a long time)
- Fixed wrong arguments to make_cond_for_table() for join_tab_idx_arg
  from false to 0.

One of the result was reducing the size if class Item with ~24 bytes

1 files changed, 2 insertions, 1 deletions

diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index 36300e57f03..70a23ebf294 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -879,7 +879,8 @@ public:
   bool fix_length_and_dec()
   {
     max_length= 512 * system_charset_info->mbmaxlen;
-    null_value= maybe_null= false;
+    null_value= false;
+    maybe_null= false;
     return FALSE;
   }
   Item *get_copy(THD *thd)