Fix of LP bug#968720.

When a view/derived table is converted from merged to materialized the
items from the used_item lists are substituted for items referring to
the fields of the result of the materialization. The problem appeared
with queries employing natural joins. Since the resolution of a natural
join was performed only once the used_item list formed at the second
execution of the query lacked the references to the fields that were
used only in the equality predicates generated for the natural join.

1 files changed, 20 insertions, 0 deletions

diff --git a/sql/sql_list.h b/sql/sql_list.h
index adedd9a3a4d..e71fdc83177 100644
--- a/sql/sql_list.h
+++ b/sql/sql_list.h
@@ -257,6 +257,26 @@ public:
       last= &first;
     return tmp->info;
   }
+
+  /**
+    Cut the list with leaving not more then n elements
+  */
+  inline uint cut(uint n)
+  {
+    list_node *element= first;
+    uint i= 0;
+    for (;
+         i < n && element != &end_of_list;
+         element= element->next, i++);
+    if (element != &end_of_list)
+    {
+      elements= i + 1;
+      last= &element->next;
+      element->next= &end_of_list;
+    }
+    return i + 1;
+  }
+
   /*
     Remove from this list elements that are contained in the passed list. 
     We assume that the passed list is a tail of this list (that is, the whole