Fixed LP bug #809179.

The attribute not_null_tables could be calculated incorrectly in the
function SELECT_LEX::update_used_tables for queries over views 
with row items in the WHERE clause. It happened because no 
implementation of the virtual callback function eval_not_null_tables
was provided for the class Item_row.
Also slightly optimized the code calculating the value of the maybe_null
flag for tables in the function SELECT_LEX::update_used_tables.

3 files changed, 28 insertions, 5 deletions

diff --git a/sql/item_row.cc b/sql/item_row.cc
index 99a1644cc48..09977d71bb7 100644
--- a/sql/item_row.cc
+++ b/sql/item_row.cc
@@ -93,6 +93,22 @@ bool Item_row::fix_fields(THD *thd, Item **ref)
 }
 
 
+bool
+Item_row::eval_not_null_tables(uchar *opt_arg)
+{
+  Item **arg,**arg_end;
+  not_null_tables_cache= 0;
+  if (arg_count)
+  {		
+    for (arg= items, arg_end= items+arg_count; arg != arg_end ; arg++)
+    {
+      not_null_tables_cache|= (*arg)->not_null_tables();
+    }
+  }
+  return FALSE;
+}
+
+
 void Item_row::cleanup()
 {
   DBUG_ENTER("Item_row::cleanup");
diff --git a/sql/item_row.h b/sql/item_row.h
index 0b43309391d..1572ef77b79 100644
--- a/sql/item_row.h
+++ b/sql/item_row.h
@@ -73,6 +73,7 @@ public:
 
   bool walk(Item_processor processor, bool walk_subquery, uchar *arg);
   Item *transform(Item_transformer transformer, uchar *arg);
+  bool eval_not_null_tables(uchar *opt_arg);
 
   uint cols() { return arg_count; }
   Item* element_index(uint i) { return items[i]; }
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 80a80363cc0..c8b5a3439b0 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -3472,18 +3472,24 @@ void SELECT_LEX::update_used_tables()
   List_iterator<TABLE_LIST> ti(leaf_tables);
   while ((tl= ti++))
   {
-    for (embedding= tl;
-         !tl->table->maybe_null && embedding;
-         embedding= embedding->embedding)
+    TABLE_LIST *embedding;
+    embedding= tl;
+    do
     {
-      tl->table->maybe_null= test(embedding->outer_join);
+      bool maybe_null;
+      if ((maybe_null= test(embedding->outer_join)))
+      {
+	tl->table->maybe_null= maybe_null;
+        break;
+      }
     }
+    while ((embedding= embedding->embedding));
     if (tl->on_expr)
     {
       tl->on_expr->update_used_tables();
       tl->on_expr->walk(&Item::eval_not_null_tables, 0, NULL);
     }
-    TABLE_LIST *embedding= tl->embedding;
+    embedding= tl->embedding;
     while (embedding)
     {
       if (embedding->on_expr &&