Applied Sanja's patch to fix LP bug #784297 in the tree for mwl106.

The patch imposes unconditional materialization for derived tables
used in update and multi-update statements.
Fixed a bug with a wrong order of processing derived tables/views
at the prepare stage that caused a crash for the variant of the 
query from test case for bug 52157.

4 files changed, 32 insertions, 6 deletions

diff --git a/sql/sql_lex.h b/sql/sql_lex.h
index a587a01b3f4..014bcfdfd65 100644
--- a/sql/sql_lex.h
+++ b/sql/sql_lex.h
@@ -585,6 +585,8 @@ public:
   void set_thd(THD *thd_arg) { thd= thd_arg; }
   inline bool is_union (); 
 
+  void set_unique_exlude();
+
   friend void lex_start(THD *thd);
   friend int subselect_union_engine::exec();
 
diff --git a/sql/sql_union.cc b/sql/sql_union.cc
index 255f5311ac3..c6a6349fd4e 100644
--- a/sql/sql_union.cc
+++ b/sql/sql_union.cc
@@ -944,3 +944,27 @@ void st_select_lex::cleanup_all_joins(bool full)
     for (sl= unit->first_select(); sl; sl= sl->next_select())
       sl->cleanup_all_joins(full);
 }
+
+
+/**
+  Set exclude_from_table_unique_test for selects of this unit and all
+  underlying selects.
+
+  @note used to exclude materialized derived tables (views) from unique
+  table check.
+*/
+
+void st_select_lex_unit::set_unique_exlude()
+{
+  for (SELECT_LEX *sl= first_select(); sl; sl= sl->next_select())
+  {
+    sl->exclude_from_table_unique_test= TRUE;
+    for (SELECT_LEX_UNIT *unit= sl->first_inner_unit();
+         unit;
+         unit= unit->next_unit())
+    {
+      unit->set_unique_exlude();
+    }
+  }
+}
+
diff --git a/sql/sql_update.cc b/sql/sql_update.cc
index 215c5cbd4b3..4821fc2bd8f 100644
--- a/sql/sql_update.cc
+++ b/sql/sql_update.cc
@@ -1040,8 +1040,8 @@ reopen_tables:
   //We need to merge for insert prior to prepare.
   if (mysql_handle_list_of_derived(lex, table_list, DT_MERGE_FOR_INSERT))
     DBUG_RETURN(1);
-  if  (mysql_handle_list_of_derived(lex, table_list, DT_PREPARE))
-    DBUG_RETURN(1);
+  if (mysql_handle_derived(lex, DT_PREPARE))
+    DBUG_RETURN(TRUE);
 
   if (setup_tables_and_check_access(thd, &lex->select_lex.context,
                                     &lex->select_lex.top_join_list,
diff --git a/sql/table.cc b/sql/table.cc
index 290a82eb56a..3e6b683eafb 100644
--- a/sql/table.cc
+++ b/sql/table.cc
@@ -5851,7 +5851,9 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
   if (!is_view())
   {
     /* A subquery might be forced to be materialized due to a side-effect. */
-    if (!is_materialized_derived() && first_select->is_mergeable())
+    if (!is_materialized_derived() && first_select->is_mergeable() &&
+        !(thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
+          thd->lex->sql_command == SQLCOM_UPDATE))
       set_merged_derived();
     else
       set_materialized_derived();
@@ -5862,9 +5864,7 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
   */
   if (is_materialized_derived())
   {
-    SELECT_LEX *sl;
-    for (sl= first_select ;sl ; sl= sl->next_select())
-      sl->exclude_from_table_unique_test= TRUE;
+    unit->master_unit()->set_unique_exlude();
   }
   /*
     Create field translation for mergeable derived tables/views.