rocksdb.ttl_secondary failed in buildbot with timeout

rocksdb.ttl_secondary                    w2 [ fail ]  timeout after 900 seconds

        Test ended at 2018-07-18 16:55:22

Test case timeout after 900 seconds

== /dev/shm/var/2/log/ttl_secondary.log == 

a INT PRIMARY KEY,

b INT,

KEY (b)

) ENGINE=rocksdb

COMMENT='ttl_duration=100;';

ALTER TABLE t1 DROP PRIMARY KEY;

ERROR HY000: TTL support is currently disabled when table has a hidden PK.

DROP TABLE t1;

CREATE TABLE t1 (

a INT PRIMARY KEY,

b INT,

KEY kb (b)

) ENGINE=rocksdb

COMMENT='ttl_duration=5;';

INSERT INTO t1 VALUES (1,1);

INSERT INTO t1 VALUES (2,2);

ALTER TABLE t1 DROP PRIMARY KEY, ADD PRIMARY KEY(b);

set global rocksdb_debug_ttl_snapshot_ts = -3600;

set global rocksdb_force_flush_memtable_now=1;

set @@global.rocksdb_compact_cf = 'default';

 == /dev/shm/var/2/tmp/analyze-timeout-mysqld.1.err ==

mysqltest: Could not open connection 'default' after 500 attempts: 2002 Can't connect to local MySQL server through socket '/dev/shm/var/tmp/2/mysqld.1.sock' (111)