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, 1 insertions, 1 deletions

diff --git a/sql/table.h b/sql/table.h
index b29199e975a..9c87f9809ff 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -366,7 +366,7 @@ enum enum_vcol_update_mode
 
 /* Field visibility enums */
 
-enum field_visibility_t {
+enum __attribute__((packed)) field_visibility_t {
   VISIBLE= 0,
   INVISIBLE_USER,
   /* automatically added by the server. Can be queried explicitly