Merge moonbone.local:/work/15351-bug-4.1-mysql

into moonbone.local:/home/evgen/bk-trees/mysql-4.1-opt

1 files changed, 4 insertions, 1 deletions

diff --git a/sql/item_strfunc.cc b/sql/item_strfunc.cc
index e817edac6c0..deb3542f4a5 100644
--- a/sql/item_strfunc.cc
+++ b/sql/item_strfunc.cc
@@ -268,11 +268,13 @@ String *Item_func_concat::val_str(String *str)
   DBUG_ASSERT(fixed == 1);
   String *res,*res2,*use_as_buff;
   uint i;
+  bool is_const= 0;
 
   null_value=0;
   if (!(res=args[0]->val_str(str)))
     goto null;
   use_as_buff= &tmp_value;
+  is_const= args[0]->const_item();
   for (i=1 ; i < arg_count ; i++)
   {
     if (res->length() == 0)
@@ -295,7 +297,7 @@ String *Item_func_concat::val_str(String *str)
 			    current_thd->variables.max_allowed_packet);
 	goto null;
       }
-      if (res->alloced_length() >= res->length()+res2->length())
+      if (!is_const && res->alloced_length() >= res->length()+res2->length())
       {						// Use old buffer
 	res->append(*res2);
       }
@@ -350,6 +352,7 @@ String *Item_func_concat::val_str(String *str)
 	res= &tmp_value;
 	use_as_buff=str;
       }
+      is_const= 0;
     }
   }
   res->set_charset(collation.collation);