Fixed LP BUG#800696.

The problem was that optimizer removes some outer references (it they are
constant for example) and the list of outer items built during prepare phase is
not actual during execution phase when we need it as the cache parameters.
First solution was use pointer on pointer on outer reference Item and
initialize temporary table on demand. This solved most problem except case
when optimiser also reduce Item which contains outer references ('OR' in
this bug test suite).

The solution is to build the list of outer reference items on execution
phase (after optimization) on demand (just before temporary table creation)
by walking Item tree and finding outer references among Item_ident
(Item_field/Item_ref) and Item_sum items.

Removed depends_on list (because it is not neede any mnore for the cache, in the place where it was used it replaced with upper_refs).

Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references (or other expression parameters in future).

mysql-test/r/subselect_cache.result:
  A new test added.
mysql-test/r/subselect_scache.result:
  Changes in creating the cache and its paremeters order or adding arguments of aggregate function (which is a parameter also, but this has no influence on the result).
mysql-test/t/subselect_cache.test:
  Added a new test.
sql/item.cc:
  depends_on removed.
  
  Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
  
  Item_cache_wrapper collect parameters befor initialization of its cache.
sql/item.h:
  depends_on removed.
  
  Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
sql/item_cmpfunc.cc:
  depends_on removed.
  
  Added processor (collect_outer_ref_processor) to collect outer references.
sql/item_cmpfunc.h:
  Added processor (collect_outer_ref_processor) to collect outer references.
sql/item_subselect.cc:
  depends_on removed.
  Added processor get_cache_parameters() method to collect outer references.
sql/item_subselect.h:
  depends_on removed.
  Added processor get_cache_parameters() method to collect outer references.
sql/item_sum.cc:
  Added processor (collect_outer_ref_processor) method to collect outer references.
sql/item_sum.h:
  Added processor (collect_outer_ref_processor) and get_cache_parameters() methods to collect outer references.
sql/opt_range.cc:
  depends_on removed.
sql/sql_base.cc:
  depends_on removed.
sql/sql_class.h:
  New iterator added.
sql/sql_expression_cache.cc:
  Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done).
sql/sql_expression_cache.h:
  Build of list of items resolved in outer query done just before creating expression cache on the first execution of the subquery which removes influence of optimizer removing items (all optimization already done).
sql/sql_lex.cc:
  depends_on removed.
sql/sql_lex.h:
  depends_on removed.
sql/sql_list.h:
  Added add_unique method to add only unique elements to the list.
sql/sql_select.cc:
  Support of new Item list added.
sql/sql_select.h:
  Support of new Item list added.

1 files changed, 52 insertions, 0 deletions

diff --git a/mysql-test/t/subselect_cache.test b/mysql-test/t/subselect_cache.test
index 12f42aab7d6..3d8de4e4808 100644
--- a/mysql-test/t/subselect_cache.test
+++ b/mysql-test/t/subselect_cache.test
@@ -1567,6 +1567,7 @@ FROM t2 ) AND table1 .`col_varchar_key` OR table1 .`pk` ;
 drop table t1,t2;
 set @@optimizer_switch= default;
 
+set optimizer_switch='subquery_cache=on';
 #
 --echo # LP BUG#615378 (incorrect NULL result returning in Item_cache)
 #
@@ -1614,3 +1615,54 @@ GROUP BY field3
 HAVING (field3 <= 'h' AND field2 != 4) ;
 --enable_warnings
 drop tables t1, t2, t3;
+
+--echo #
+--echo # Test aggregate functions as parameters to subquery cache
+--echo #
+
+CREATE TABLE t1 ( a INT, b INT, c INT, KEY (a, b));
+
+INSERT INTO t1 VALUES
+  ( 1, 1,  1 ),
+  ( 1, 2,  2 ),
+  ( 1, 3,  3 ),
+  ( 1, 4,  6 ),
+  ( 1, 5,  5 ),
+  ( 1, 9, 13 ),
+
+  ( 2, 1,  6 ),
+  ( 2, 2,  7 ),
+  ( 2, 3,  8 );
+
+SELECT a, AVG(t1.b),
+(SELECT t11.c FROM t1 t11 WHERE t11.a = t1.a AND t11.b = AVG(t1.b)) AS t11c
+FROM t1 GROUP BY a;
+
+DROP TABLE t1;
+
+--echo #
+--echo # Test of LP BUG#800696 (deleting list of Items (OR arguments) 
+--echo # in optimization)
+--echo #
+
+set optimizer_switch='subquery_cache=on,in_to_exists=on';
+CREATE TABLE t1 ( f3 int) ;
+INSERT INTO t1 VALUES (0),(0);
+
+CREATE TABLE t3 ( f3 int) ;
+INSERT INTO t3 VALUES (0),(0);
+
+CREATE TABLE t2 ( f1 int, f2 int, f3 int) ;
+INSERT INTO t2 VALUES (7,0,0);
+
+SELECT *
+FROM t2, t3
+WHERE t2.f2 OR t3.f3 IN
+(
+SELECT t2.f2
+FROM t1
+WHERE t2.f1 OR t2.f3 );
+drop tables t1, t2, t3;
+
+--echo # restore default
+set @@optimizer_switch= default;