Comment 1 for bug 671340

Test case:

--source include/have_innodb.inc

SET SESSION optimizer_switch='index_condition_pushdown=off';
SET SESSION join_cache_level=5;
SET SESSION join_buffer_size=1;
SET SESSION mrr_buffer_size=100000;

--disable_warnings
DROP TABLE /*! IF EXISTS */ t1;
DROP TABLE /*! IF EXISTS */ t2;
--enable_warnings

CREATE TABLE t1 (
  pk int(11) NOT NULL AUTO_INCREMENT,
  col_int_key int(11) NOT NULL,
  col_varchar_key varchar(1) NOT NULL,
  col_varchar_nokey varchar(1) NOT NULL,
  PRIMARY KEY (pk),
  KEY col_int_key (col_int_key),
  KEY col_varchar_key (col_varchar_key,col_int_key)
) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES (10,8,'v','v'),(11,8,'f','f'),(12,5,'v','v'),(13,8,'s','s'),(14,8,'a','a'),(15,6,'p','p'),(16,7,'z','z'),(17,2,'a','a'),(18,5,'h','h'),(19,7,'h','h'),(20,2,'v','v'),(21,9,'v','v'),(22,142,'b','b'),(23,3,'y','y'),(24,0,'v','v'),(25,3,'m','m'),(26,5,'z','z'),(27,9,'n','n'),(28,1,'d','d'),(29,107,'a','a');
CREATE TABLE t2 (
  pk int(11) NOT NULL AUTO_INCREMENT,
  col_int_key int(11) NOT NULL,
  col_varchar_key varchar(1) NOT NULL,
  col_varchar_nokey varchar(1) NOT NULL,
  PRIMARY KEY (pk),
  KEY col_int_key (col_int_key),
  KEY col_varchar_key (col_varchar_key,col_int_key)
) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=latin1;
INSERT INTO t2 VALUES (1,9,'x','x'),(2,5,'g','g'),(3,1,'o','o'),(4,0,'g','g'),(5,1,'v','v'),(6,190,'m','m'),(7,6,'x','x'),(8,3,'c','c'),(9,4,'z','z'),(10,3,'i','i'),(11,186,'x','x'),(12,1,'g','g'),(13,8,'q','q'),(14,226,'m','m'),(15,133,'p','p'),(16,6,'e','e'),(17,3,'t','t'),(18,8,'j','j'),(19,5,'h','h'),(20,7,'w','w');

SET optimizer_switch='mrr_sort_keys=on';

EXPLAIN SELECT table2.pk , table1.col_int_key
FROM t2 AS table1 JOIN
( t1 AS table2 JOIN t2 AS table3 ON table3.col_varchar_nokey = table2.col_varchar_key )
 ON table3.pk > table2.col_varchar_nokey
ORDER BY table1.pk ;

CREATE TABLE p1 AS SELECT table2.pk , table1.col_int_key
FROM t2 AS table1 JOIN
( t1 AS table2 JOIN t2 AS table3 ON table3.col_varchar_nokey = table2.col_varchar_key )
 ON table3.pk > table2.col_varchar_nokey
ORDER BY table1.pk ;

SET optimizer_switch='mrr_sort_keys=off';

EXPLAIN SELECT table2.pk , table1.col_int_key
FROM t2 AS table1 JOIN
( t1 AS table2 JOIN t2 AS table3 ON table3.col_varchar_nokey = table2.col_varchar_key )
 ON table3.pk > table2.col_varchar_nokey
ORDER BY table1.pk ;

CREATE TABLE p2 AS SELECT table2.pk , table1.col_int_key
FROM t2 AS table1 JOIN
( t1 AS table2 JOIN t2 AS table3 ON table3.col_varchar_nokey = table2.col_varchar_key )
 ON table3.pk > table2.col_varchar_nokey
ORDER BY table1.pk ;

--let $diff_table_1 = test.p1
--let $diff_table_2 = test.p2
--source include/diff_tables.inc