InnoDB statistics in extended slow query log always zero

# InnoDB_trx_id: 509
#   InnoDB_IO_r_ops: 0  InnoDB_IO_r_bytes: 0  InnoDB_IO_r_wait: 0.000000
#   InnoDB_rec_lock_wait: 0.000000  InnoDB_queue_wait: 0.000000
#   InnoDB_pages_distinct: 0

# InnoDB_trx_id: 509
#   InnoDB_IO_r_ops: 1  InnoDB_IO_r_bytes: 16384  InnoDB_IO_r_wait: 0.000024
#   InnoDB_rec_lock_wait: 2.004502  InnoDB_queue_wait: 0.000000
#   InnoDB_pages_distinct: 6

--source include/have_innodb.inc

CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=InnoDB;

INSERT INTO t1 VALUES (1);

BEGIN;
SELECT * FROM t1 FOR UPDATE;

--source include/count_sessions.inc

--connect(con1,localhost,root,,)

SET SESSION log_slow_verbosity='innodb';
SET SESSION long_query_time=0;
--let log_file=percona.slow_extended_lock_time.log
--source include/log_start.inc

send DELETE FROM t1 WHERE a = 1;

--connection default

# TODO wait condition
--real_sleep 2
SHOW PROCESSLIST;

ROLLBACK;

--connection con1

reap;
--source include/log_stop.inc

--disconnect con1
--connection default

DROP TABLE t1;

--source include/wait_until_count_sessions.inc

--cat_file $MYSQLTEST_VARDIR/$log_file.slog
--source include/log_cleanup.inc