MDEV-17096 Pushdown of simple derived tables to storage engines

MDEV-17631 select_handler for a full query pushdown

Interfaces + Proof of Concept for federatedx with test cases.

The interfaces have been developed for integration of ColumnStore engine.

1 files changed, 45 insertions, 1 deletions

diff --git a/sql/sql_select.h b/sql/sql_select.h
index 4140a0293f8..bca2387e1a0 100644
--- a/sql/sql_select.h
+++ b/sql/sql_select.h
@@ -2442,9 +2442,53 @@ public:
   ~Pushdown_query() { delete handler; }
 
   /* Function that calls the above scan functions */
-  int execute(JOIN *join);
+  int execute(JOIN *);
 };
 
+class derived_handler;
+
+class Pushdown_derived: public Sql_alloc
+{
+private:
+  bool is_analyze;
+public:
+  TABLE_LIST *derived;
+  derived_handler *handler;
+
+  Pushdown_derived(TABLE_LIST *tbl, derived_handler *h);
+
+  ~Pushdown_derived();
+
+  int execute(); 
+};
+
+
+class select_handler;
+
+
+class Pushdown_select: public Sql_alloc
+{
+private:
+  bool is_analyze;
+  List<Item> result_columns;
+  bool send_result_set_metadata();
+  bool send_data();
+  bool send_eof();
+
+public:
+  SELECT_LEX *select;
+  select_handler *handler;
+
+  Pushdown_select(SELECT_LEX *sel, select_handler *h);
+
+  ~Pushdown_select();
+
+  bool init();
+
+  int execute(); 
+};
+
+
 bool test_if_order_compatible(SQL_I_List<ORDER> &a, SQL_I_List<ORDER> &b);
 int test_if_group_changed(List<Cached_item> &list);
 int create_sort_index(THD *thd, JOIN *join, JOIN_TAB *tab, Filesort *fsort);