Merge 5.5->10.0-base

6 files changed, 48 insertions, 10 deletions

diff --git a/sql/item.cc b/sql/item.cc
index 1d8e466b2fd..a425b0cd4ce 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -8109,7 +8109,7 @@ bool Item_default_value::fix_fields(THD *thd, Item **items)
   }
   if (!(def_field= (Field*) sql_alloc(field_arg->field->size_of())))
     goto error;
-  memcpy(def_field, field_arg->field, field_arg->field->size_of());
+  memcpy((void *)def_field, (void *)field_arg->field, field_arg->field->size_of());
   def_field->move_field_offset((my_ptrdiff_t)
                                (def_field->table->s->default_values -
                                 def_field->table->record[0]));
@@ -8245,7 +8245,7 @@ bool Item_insert_value::fix_fields(THD *thd, Item **items)
     Field *def_field= (Field*) sql_alloc(field_arg->field->size_of());
     if (!def_field)
       return TRUE;
-    memcpy(def_field, field_arg->field, field_arg->field->size_of());
+    memcpy((void *)def_field, (void *)field_arg->field, field_arg->field->size_of());
     def_field->move_field_offset((my_ptrdiff_t)
                                  (def_field->table->insert_values -
                                   def_field->table->record[0]));
diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index f2ef955af05..0544dceb9a0 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -559,8 +559,19 @@ bool Item_subselect::is_expensive()
     if (!cur_join)
       continue;
 
-    /* If a subquery is not optimized we cannot estimate its cost. */
-    if (!cur_join->join_tab)
+    /*
+      Subqueries whose result is known after optimization are not expensive.
+      Such subqueries have all tables optimized away, thus have no join plan.
+    */
+    if (cur_join->optimized &&
+        (cur_join->zero_result_cause || !cur_join->tables_list))
+      return false;
+
+    /*
+      If a subquery is not optimized we cannot estimate its cost. A subquery is
+      considered optimized if it has a join plan.
+    */
+    if (!(cur_join->optimized && cur_join->join_tab))
       return true;
 
     if (sl->first_inner_unit())
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 9410a12f21b..03afd1a4365 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -735,7 +735,15 @@ int simple_raw_key_cmp(void* arg, const void* key1, const void* key2)
 }
 
 
-int item_sum_distinct_walk(void *element, element_count num_of_dups,
+static int item_sum_distinct_walk_for_count(void *element, 
+                                            element_count num_of_dups,
+                                            void *item)
+{
+  return ((Aggregator_distinct*) (item))->unique_walk_function_for_count(element);
+}
+ 
+
+static int item_sum_distinct_walk(void *element, element_count num_of_dups,
                                   void *item)
 {
   return ((Aggregator_distinct*) (item))->unique_walk_function(element);
@@ -1105,7 +1113,12 @@ void Aggregator_distinct::endup()
   {
     /* go over the tree of distinct keys and calculate the aggregate value */
     use_distinct_values= TRUE;
-    tree->walk(table, item_sum_distinct_walk, (void*) this);
+    tree_walk_action func;
+    if (item_sum->sum_func() == Item_sum::COUNT_DISTINCT_FUNC)
+      func= item_sum_distinct_walk_for_count;
+    else
+      func= item_sum_distinct_walk;
+    tree->walk(table, func, (void*) this);
     use_distinct_values= FALSE;
   }
   /* prevent consecutive recalculations */
@@ -1482,6 +1495,22 @@ bool Aggregator_distinct::unique_walk_function(void *element)
 }
 
 
+/*
+  A variant of unique_walk_function() that is to be used with Item_sum_count.
+
+  COUNT is a special aggregate function: it doesn't need the values, it only
+  needs to count them. COUNT needs to know the values are not NULLs, but NULL
+  values are not put into the Unique, so we don't need to check for NULLs here.
+*/
+
+bool Aggregator_distinct::unique_walk_function_for_count(void *element)
+{
+  Item_sum_count *sum= (Item_sum_count *)item_sum;
+  sum->count++;
+  return 0;
+}
+
+
 Aggregator_distinct::~Aggregator_distinct()
 {
   if (tree)
diff --git a/sql/item_sum.h b/sql/item_sum.h
index 40a28d8beae..a954b0f65c1 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -642,6 +642,7 @@ public:
   virtual bool arg_is_null();
 
   bool unique_walk_function(void *element);
+  bool unique_walk_function_for_count(void *element);
   static int composite_key_cmp(void* arg, uchar* key1, uchar* key2);
 };
 
diff --git a/sql/sql_const.h b/sql/sql_const.h
index c6aa52197d5..7dadbb7b8b4 100644
--- a/sql/sql_const.h
+++ b/sql/sql_const.h
@@ -93,7 +93,7 @@
 #define FIELD_NR_MASK	16383			/* To get fieldnumber */
 #define FERR		-1			/* Error from my_functions */
 #define CREATE_MODE	0			/* Default mode on new files */
-#define NAMES_SEP_CHAR	'\377'			/* Char to sep. names */
+#define NAMES_SEP_CHAR	255			/* Char to sep. names */
 
 #define READ_RECORD_BUFFER	(uint) (IO_SIZE*8) /* Pointer_buffer_size */
 #define DISK_BUFFER_SIZE	(uint) (IO_SIZE*16) /* Size of diskbuffer */
diff --git a/sql/sql_select.cc b/sql/sql_select.cc
index 0abac42eb73..ad4324fa7d1 100644
--- a/sql/sql_select.cc
+++ b/sql/sql_select.cc
@@ -13037,9 +13037,6 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top,
         table->prep_on_expr= table->on_expr= 0;
       }
     }
-    
-    if (!top)
-      continue;
 
     /* 
       Only inner tables of non-convertible outer joins