tokudb patches for prepare range scan

sql/handler.h

@@ -1868,6 +1868,16 @@ public:
   }
   /* This is called after index_init() if we need to do a index scan */
   virtual int prepare_index_scan() { return 0; }
+  virtual int prepare_index_key_scan_map(const uchar * key, key_part_map keypart_map)
+  {
+    uint key_len= calculate_key_len(table, active_index, key, keypart_map);
+    return  prepare_index_key_scan(key, key_len);
+  }
+  virtual int prepare_index_key_scan( const uchar * key, uint key_len )
+  { return 0; }
+  virtual int prepare_range_scan(const key_range *start_key, const key_range *end_key)
+  { return 0; }
+
   int ha_rnd_init(bool scan) __attribute__ ((warn_unused_result))
   {
     DBUG_EXECUTE_IF("ha_rnd_init_fail", return HA_ERR_TABLE_DEF_CHANGED;);

sql/opt_range.cc

@@ -11390,6 +11390,26 @@ int QUICK_SELECT_DESC::get_next()
     if (!(last_range= rev_it++))
       DBUG_RETURN(HA_ERR_END_OF_FILE);		// All ranges used
 
+    key_range       start_key;
+    start_key.key=    (const uchar*) last_range->min_key;
+    start_key.length= last_range->min_length;
+    start_key.flag=   ((last_range->flag & NEAR_MIN) ? HA_READ_AFTER_KEY :
+                       (last_range->flag & EQ_RANGE) ?
+                       HA_READ_KEY_EXACT : HA_READ_KEY_OR_NEXT);
+    start_key.keypart_map= last_range->min_keypart_map;
+    key_range       end_key;
+    end_key.key=      (const uchar*) last_range->max_key;
+    end_key.length=   last_range->max_length;
+    end_key.flag=     (last_range->flag & NEAR_MAX ? HA_READ_BEFORE_KEY :
+                       HA_READ_AFTER_KEY);
+    end_key.keypart_map= last_range->max_keypart_map;
+    result= file->prepare_range_scan((last_range->flag & NO_MIN_RANGE) ? NULL : &start_key,
+                                     (last_range->flag & NO_MAX_RANGE) ? NULL : &end_key);
+    if (result)
+    {
+      DBUG_RETURN(result);
+    }
+
     if (last_range->flag & NO_MAX_RANGE)        // Read last record
     {
       int local_error;

sql/records.cc

@@ -371,7 +371,15 @@ static int rr_quick(READ_RECORD *info)
 
 static int rr_index_first(READ_RECORD *info)
 {
-  int tmp= info->table->file->ha_index_first(info->record);
+  int tmp;
+  // tell handler that we are doing an index scan
+  if ((tmp = info->table->file->prepare_index_scan())) 
+  {
+    tmp= rr_handle_error(info, tmp);
+    return tmp;
+  }
+
+  tmp= info->table->file->ha_index_first(info->record);
   info->read_record= rr_index;
   if (tmp)
     tmp= rr_handle_error(info, tmp);

sql/sql_select.cc

@@ -17291,6 +17291,11 @@ join_read_always_key(JOIN_TAB *tab)
 
   if (cp_buffer_from_ref(tab->join->thd, table, &tab->ref))
     return -1;
+  if ((error= table->file->prepare_index_key_scan_map(tab->ref.key_buff, make_prev_keypart_map(tab->ref.key_parts)))) 
+  {
+    report_error(table,error);
+    return -1;
+  }
   if ((error= table->file->ha_index_read_map(table->record[0],
                                              tab->ref.key_buff,
                                              make_prev_keypart_map(tab->ref.key_parts),
@@ -17324,6 +17329,11 @@ join_read_last_key(JOIN_TAB *tab)
 
   if (cp_buffer_from_ref(tab->join->thd, table, &tab->ref))
     return -1;
+  if ((error= table->file->prepare_index_key_scan_map(tab->ref.key_buff, make_prev_keypart_map(tab->ref.key_parts)))) 
+  {
+    report_error(table,error);
+    return -1;
+  }
   if ((error= table->file->ha_index_read_map(table->record[0],
                                             tab->ref.key_buff,
                                      make_prev_keypart_map(tab->ref.key_parts),