Subquery optimizations: non-semijoin materialization

- Backport into Maria DB 5.3, part 1

1 files changed, 21 insertions, 8 deletions

diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index b161da86dbd..2ee73ff962c 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -2076,16 +2076,28 @@ void st_select_lex::print_limit(THD *thd,
 {
   SELECT_LEX_UNIT *unit= master_unit();
   Item_subselect *item= unit->item;
-  if (item && unit->global_parameters == this &&
-      (item->substype() == Item_subselect::EXISTS_SUBS ||
-       item->substype() == Item_subselect::IN_SUBS ||
-       item->substype() == Item_subselect::ALL_SUBS))
+
+  if (item && unit->global_parameters == this)
   {
-    DBUG_ASSERT(!item->fixed ||
-                (select_limit->val_int() == LL(1) && offset_limit == 0));
-    return;
+    Item_subselect::subs_type subs_type= item->substype();
+    if (subs_type == Item_subselect::EXISTS_SUBS ||
+        subs_type == Item_subselect::IN_SUBS ||
+        subs_type == Item_subselect::ALL_SUBS)
+    {
+      DBUG_ASSERT(!item->fixed ||
+                  /*
+                    If not using materialization both:
+                    select_limit == 1, and there should be no offset_limit.
+                  */
+                  (((subs_type == Item_subselect::IN_SUBS) &&
+                    ((Item_in_subselect*)item)->exec_method ==
+                    Item_in_subselect::MATERIALIZATION) ?
+                   TRUE :
+                   (select_limit->val_int() == 1LL) &&
+                   offset_limit == 0));
+      return;
+    }
   }
-
   if (explicit_limit)
   {
     str->append(STRING_WITH_LEN(" limit "));
@@ -2098,6 +2110,7 @@ void st_select_lex::print_limit(THD *thd,
   }
 }
 
+
 /**
   @brief Restore the LEX and THD in case of a parse error.