Merge station.:/mnt/raid/alik/MySQL/devel/5.1

into  station.:/mnt/raid/alik/MySQL/devel/5.1-rt


client/mysqltest.c:
  Auto merged
include/mysql_com.h:
  Auto merged
libmysqld/emb_qcache.cc:
  Auto merged
libmysqld/emb_qcache.h:
  Auto merged
libmysqld/lib_sql.cc:
  Auto merged
mysql-test/lib/mtr_report.pl:
  Auto merged
sql/ha_partition.cc:
  Auto merged
sql/item_func.cc:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/opt_range.cc:
  Auto merged
sql/set_var.cc:
  Auto merged
sql/set_var.h:
  Auto merged
sql/slave.cc:
  Auto merged
sql/sql_class.cc:
  Auto merged
sql/sql_class.h:
  Auto merged
sql/sql_db.cc:
  Auto merged
sql/sql_insert.cc:
  Auto merged
sql/sql_parse.cc:
  Auto merged
sql/sql_partition.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/sql_table.cc:
  Auto merged
sql/table.cc:
  Auto merged
storage/myisam/ha_myisam.cc:
  Auto merged
sql/protocol.cc:
  SCCS merged

1 files changed, 19 insertions, 2 deletions

diff --git a/sql/item.h b/sql/item.h
index 2219153616b..b98389bc8d4 100644
--- a/sql/item.h
+++ b/sql/item.h
@@ -2622,16 +2622,23 @@ class Item_cache: public Item
 protected:
   Item *example;
   table_map used_table_map;
+  /*
+    Field that this object will get value from. This is set/used by 
+    index-based subquery engines to detect and remove the equality injected 
+    by IN->EXISTS transformation.
+    For all other uses of Item_cache, cached_field doesn't matter.
+  */  
+  Field *cached_field;
   enum enum_field_types cached_field_type;
 public:
   Item_cache(): 
-    example(0), used_table_map(0), cached_field_type(MYSQL_TYPE_STRING) 
+    example(0), used_table_map(0), cached_field(0), cached_field_type(MYSQL_TYPE_STRING) 
   {
     fixed= 1; 
     null_value= 1;
   }
   Item_cache(enum_field_types field_type_arg):
-    example(0), used_table_map(0), cached_field_type(field_type_arg)
+    example(0), used_table_map(0), cached_field(0), cached_field_type(field_type_arg)
   {
     fixed= 1;
     null_value= 1;
@@ -2647,6 +2654,8 @@ public:
     decimals= item->decimals;
     collation.set(item->collation);
     unsigned_flag= item->unsigned_flag;
+    if (item->type() == FIELD_ITEM)
+      cached_field= ((Item_field *)item)->field;
     return 0;
   };
   virtual void store(Item *)= 0;
@@ -2658,6 +2667,14 @@ public:
   // to prevent drop fixed flag (no need parent cleanup call)
   void cleanup() {}
   void print(String *str);
+  bool eq_def(Field *field) 
+  { 
+    return cached_field ? cached_field->eq_def (field) : FALSE;
+  }
+  bool eq(const Item *item, bool binary_cmp) const
+  {
+    return this == item;
+  }
 };