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, 7 insertions, 0 deletions

diff --git a/sql/table.h b/sql/table.h
index b75fa9074a4..33cf23b36b0 100644
--- a/sql/table.h
+++ b/sql/table.h
@@ -55,6 +55,8 @@ class Virtual_column_info;
 class Table_triggers_list;
 class TMP_TABLE_PARAM;
 class SEQUENCE;
+class derived_handler;
+class Pushdown_derived;
 
 /*
   Used to identify NESTED_JOIN structures within a join (applicable only to
@@ -2118,6 +2120,8 @@ struct TABLE_LIST
   TABLE_LIST * next_with_rec_ref;
   bool is_derived_with_recursive_reference;
   bool block_handle_derived;
+  derived_handler *dt_handler;
+  Pushdown_derived *pushdown_derived;
   ST_SCHEMA_TABLE *schema_table;        /* Information_schema table */
   st_select_lex	*schema_select_lex;
   /*
@@ -2584,6 +2588,9 @@ struct TABLE_LIST
   } 
   void set_lock_type(THD* thd, enum thr_lock_type lock);
 
+  derived_handler *find_derived_handler(THD *thd);
+  TABLE_LIST *get_first_table();
+
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);
   bool prep_where(THD *thd, Item **conds, bool no_where_clause);