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/item_cmpfunc.h b/sql/item_cmpfunc.h
index d8f884145e9..2bc3475c7e0 100644
--- a/sql/item_cmpfunc.h
+++ b/sql/item_cmpfunc.h
@@ -381,7 +381,7 @@ public:
   Item *expr_cache_insert_transformer(THD *thd, uchar *unused) override;
   bool is_expensive_processor(void *arg) override;
   bool is_expensive() override;
-  void set_join_tab_idx(uint join_tab_idx_arg) override
+  void set_join_tab_idx(uint8 join_tab_idx_arg) override
   { args[1]->set_join_tab_idx(join_tab_idx_arg); }
   void get_cache_parameters(List<Item> &parameters) override;
   bool is_top_level_item() const override;