static void make_sortkey(register Sort_param *param,

                         register uchar *to, uchar *ref_pos)

{

...

}

static uint

sortlength(THD *thd, SORT_FIELD *sortorder, uint s_length,

           bool *multi_byte_charset)

{

...

}

--- sql/filesort.cc	2014-06-12 08:57:03 +0000

+++ sql/filesort.cc	2014-06-25 13:34:23 +0000

@@ -976,6 +976,13 @@ static void make_sortkey(register Sort_p

       if ((maybe_null = field->maybe_null()))

         to++;

     }

+    else if (const Type_handler *handler= Type_handlers.handler(sort_field->item->field_type()))

+    {

+      if ((maybe_null= sort_field->item->maybe_null))

+        *to++= 1;

+      if (handler->make_sort_key(sort_field, to) && maybe_null)

+        to[-1]= '\0';

+    }

     else

     {						// Item

       Item *item=sort_field->item;

@@ -1881,6 +1887,12 @@ sortlength(THD *thd, SORT_FIELD *sortord

       if (sortorder->field->maybe_null())

 	length++;				// Place for NULL marker

     }

+    else if (const Type_handler *handler= Type_handlers.handler(sortorder->item->field_type()))

+    {

+      handler->sortlength(sortorder, sortorder->item);

+      if (sortorder->item->maybe_null)

+        length++;

+    }

     else

     {

       sortorder->result_type= sortorder->item->cmp_type();