Merge from 5.1 to 5.5

mysql-test/r/select.result:
  Added test result for Bug#12713907
mysql-test/t/select.test:
  Added test case for Bug#12713907
sql/sql_select.cc:
  Remove the call to set_keyread as we do it from access
  functions 'join_read_first' and 'join_read_last'

mysql-test/r/select.result

@@ -4988,3 +4988,30 @@ f1
 DROP TABLE t1;
 DROP VIEW view_t1;
 # End of test  BUG#63020
+#
+# Bug#12713907: STRANGE OPTIMIZE & WRONG RESULT UNDER ORDER BY 
+# COUNT(*) LIMIT.
+#
+CREATE TABLE t1 (
+id BIGINT(20) ,
+member_id_to INT(11) ,
+r_date DATE ,
+PRIMARY KEY (id,r_date),
+KEY r_date_idx (r_date),
+KEY t1_idx01 (member_id_to)
+) ENGINE=InnoDB;
+INSERT INTO t1 VALUES 
+(107924526,518491,'2011-05-01'),
+(107924527,518491,'2011-05-01'),
+(107924534,518491,'2011-06-21'),
+(107924535,518491,'2011-06-21'),
+(107924542,1601319,'2011-06-21'),
+(107924543,1601319,'2011-06-21'),
+(107924544,1601319,'2011-06-21'),
+(107924545,1601319,'2011-06-21');
+SELECT member_id_to, COUNT(*) FROM t1 WHERE r_date =
+'2011-06-21' GROUP BY member_id_to ORDER BY 2 LIMIT 1;
+member_id_to	COUNT(*)
+518491	2
+DROP TABLE t1;
+# End of test  BUG#12713907

mysql-test/t/select.test

@@ -4253,3 +4253,35 @@ DROP VIEW view_t1;
 
 --echo # End of test  BUG#63020
 
+
+--echo #
+--echo # Bug#12713907: STRANGE OPTIMIZE & WRONG RESULT UNDER ORDER BY 
+--echo # COUNT(*) LIMIT.
+--echo #
+
+CREATE TABLE t1 (
+id BIGINT(20) ,
+member_id_to INT(11) ,
+r_date DATE ,
+PRIMARY KEY (id,r_date),
+KEY r_date_idx (r_date),
+KEY t1_idx01 (member_id_to)
+) ENGINE=InnoDB;
+
+INSERT INTO t1 VALUES 
+(107924526,518491,'2011-05-01'),
+(107924527,518491,'2011-05-01'),
+(107924534,518491,'2011-06-21'),
+(107924535,518491,'2011-06-21'),
+(107924542,1601319,'2011-06-21'),
+(107924543,1601319,'2011-06-21'),
+(107924544,1601319,'2011-06-21'),
+(107924545,1601319,'2011-06-21');
+
+SELECT member_id_to, COUNT(*) FROM t1 WHERE r_date =
+  '2011-06-21' GROUP BY member_id_to ORDER BY 2 LIMIT 1;
+
+DROP TABLE t1;
+
+--echo # End of test  BUG#12713907
+

sql/sql_select.cc

@@ -13925,8 +13925,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
                                 join_read_first:join_read_last;
         tab->type=JT_NEXT;           // Read with index_first(), index_next()
 
-        if (table->covering_keys.is_set(best_key))
-          table->set_keyread(TRUE);
         table->file->ha_index_or_rnd_end();
         if (tab->join->select_options & SELECT_DESCRIBE)
         {