MDEV-15777 Use inferred IS NOT NULL predicates in the range optimizer10.3-mdev15777

This patch introduces the optimization that allows range optimizer to
consider index range scans that are built employing NOT NULL predicates
inferred from WHERE conditions and ON expressions.
The patch adds a new optimizer switch not_null_range_scan.

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/item_row.h b/sql/item_row.h
index 0d6a6db2e0e..0efa29f3d79 100644
--- a/sql/item_row.h
+++ b/sql/item_row.h
@@ -110,6 +110,7 @@ public:
   }
   Item *transform(THD *thd, Item_transformer transformer, uchar *arg);
   bool eval_not_null_tables(void *opt_arg);
+  bool find_not_null_fields(table_map allowed);
 
   uint cols() const { return arg_count; }
   Item* element_index(uint i) { return args[i]; }