This is the consolidated patch for mdev-8646:bb-10.2-mdev8646

"Re-factor the code for post-join operations".

The patch mainly contains the code ported from mysql-5.6 and
created for two essential architectural changes:
1. WL#5558: Resolve ORDER BY execution method at the optimization stage
2. WL#6071: Inline tmp tables into the nested loops algorithm

The first task was implemented for mysql-5.6 by Ole John Aske.
It allows to make all decisions on ORDER BY operation at the optimization
stage.

The second task implemented for mysql-5.6 by Evgeny Potemkin adds JOIN_TAB
nodes for post-join operations that require temporary tables. It allows
to execute these operations within the nested loops algorithm that used to
be used before this task only for join queries. Besides these task moves
all planning on the execution of these operations from the execution phase
to the optimization phase.

Some other re-factoring changes of mysql-5.6 were pulled in, mainly because
it was easier to pull them in than roll them back. In particular all
changes concerning Ref_ptr_array were incorporated.

The port required some changes in the MariaDB code that concerned the
functionality of EXPLAIN and ANALYZE. This was done mainly by Sergey
Petrunia.

1 files changed, 10 insertions, 3 deletions

diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index 9eddd6d61ee..e87fcb8cd22 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -709,6 +709,7 @@ public:
 };
 
 typedef class st_select_lex_unit SELECT_LEX_UNIT;
+typedef Bounds_checked_array<Item*> Ref_ptr_array;
 
 /*
   SELECT_LEX - store information of parsed SELECT statment
@@ -787,9 +788,9 @@ public:
   SQL_I_List<ORDER> order_list;   /* ORDER clause */
   SQL_I_List<ORDER> gorder_list;
   Item *select_limit, *offset_limit;  /* LIMIT clause parameters */
-  // Arrays of pointers to top elements of all_fields list
-  Item **ref_pointer_array;
-  size_t ref_pointer_array_size; // Number of elements in array.
+
+  /// Array of pointers to top elements of all_fields list
+  Ref_ptr_array ref_pointer_array;
 
   /*
     number of items in select_list and HAVING clause used to get number
@@ -886,6 +887,12 @@ public:
   */
   List<String> *prev_join_using;
 
+  /**
+    The set of those tables whose fields are referenced in the select list of
+    this select level.
+  */
+  table_map select_list_tables;
+
   /* namp of nesting SELECT visibility (for aggregate functions check) */
   nesting_map name_visibility_map;