Merge 10.1 into 10.2

1 files changed, 68 insertions, 1 deletions

diff --git a/sql/opt_subselect.cc b/sql/opt_subselect.cc
index 36d0116696a..d0be72b8d51 100644
--- a/sql/opt_subselect.cc
+++ b/sql/opt_subselect.cc
@@ -441,6 +441,7 @@ bool subquery_types_allow_materialization(Item_in_subselect *in_subs);
 static bool replace_where_subcondition(JOIN *, Item **, Item *, Item *, bool);
 static int subq_sj_candidate_cmp(Item_in_subselect* el1, Item_in_subselect* el2,
                                  void *arg);
+static void reset_equality_number_for_subq_conds(Item * cond);
 static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred);
 static bool convert_subq_to_jtbm(JOIN *parent_join, 
                                  Item_in_subselect *subq_pred, bool *remove);
@@ -819,6 +820,9 @@ int check_and_do_in_subquery_rewrites(JOIN *join)
           details)
         * require that compared columns have exactly the same type. This is
           a temporary measure to avoid BUG#36752-type problems.
+
+    JOIN_TAB::keyuse_is_valid_for_access_in_chosen_plan expects that for Semi Join Materialization
+    Scan all the items in the select list of the IN Subquery are of the type Item::FIELD_ITEM.
 */
 
 static 
@@ -1456,6 +1460,67 @@ static int subq_sj_candidate_cmp(Item_in_subselect* el1, Item_in_subselect* el2,
 }
 
 
+/**
+    @brief
+    reset the value of the field in_eqaulity_no for all Item_func_eq
+    items in the where clause of the subquery.
+
+    Look for in_equality_no description in Item_func_eq class
+
+    DESCRIPTION
+    Lets have an example:
+    SELECT t1.a FROM t1 WHERE t1.a IN
+      (SELECT t2.a FROM t2 where t2.b IN
+          (select t3.b from t3 where t3.c=27 ))
+
+    So for such a query we have the parent, child and
+    grandchild select.
+
+    So for the equality t2.b = t3.b we set the value for in_equality_no to
+    0 according to its description. Wewe do the same for t1.a = t2.a.
+    But when we look at the child select (with the grandchild select merged),
+    the query would be
+
+    SELECT t1.a FROM t1 WHERE t1.a IN
+      (SELECT t2.a FROM t2 where t2.b = t3.b and t3.c=27)
+
+    and then when the child select is merged into the parent select the query
+    would look like
+
+    SELECT t1.a FROM t1, semi-join-nest(t2,t3)
+            WHERE t1.a =t2.a and t2.b = t3.b and t3.c=27
+
+    Still we would have in_equality_no set for t2.b = t3.b
+    though it does not take part in the semi-join equality for the parent select,
+    so we should reset its value to UINT_MAX.
+
+    @param cond WHERE clause of the subquery
+*/
+
+static void reset_equality_number_for_subq_conds(Item * cond)
+{
+  if (!cond)
+    return;
+  if (cond->type() == Item::COND_ITEM)
+  {
+    List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
+    Item *item;
+    while ((item=li++))
+    {
+      if (item->type() == Item::FUNC_ITEM &&
+      ((Item_func*)item)->functype()== Item_func::EQ_FUNC)
+        ((Item_func_eq*)item)->in_equality_no= UINT_MAX;
+    }
+  }
+  else
+  {
+    if (cond->type() == Item::FUNC_ITEM &&
+      ((Item_func*)cond)->functype()== Item_func::EQ_FUNC)
+        ((Item_func_eq*)cond)->in_equality_no= UINT_MAX;
+  }
+  return;
+}
+
 /*
   Convert a subquery predicate into a TABLE_LIST semi-join nest
 
@@ -1719,6 +1784,7 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
   */
   sj_nest->sj_in_exprs= subq_pred->left_expr->cols();
   sj_nest->nested_join->sj_outer_expr_list.empty();
+  reset_equality_number_for_subq_conds(sj_nest->sj_on_expr);
 
   if (subq_pred->left_expr->cols() == 1)
   {
@@ -3543,7 +3609,8 @@ void fix_semijoin_strategies_for_picked_join_order(JOIN *join)
       first= tablenr - sjm->tables + 1;
       join->best_positions[first].n_sj_tables= sjm->tables;
       join->best_positions[first].sj_strategy= SJ_OPT_MATERIALIZE;
-      join->sjm_lookup_tables|= s->table->map;
+      for (uint i= first; i < first+ sjm->tables; i++)
+        join->sjm_lookup_tables |= join->best_positions[i].table->table->map;
     }
     else if (pos->sj_strategy == SJ_OPT_MATERIALIZE_SCAN)
     {