tokudb.hotindex-insert-2 failed in buildbot with timeout

tokudb.hotindex-insert-2                 w2 [ fail ]  timeout after 900 seconds

        Test ended at 2018-01-10 18:31:42

Test case timeout after 900 seconds

== /dev/shm/var/2/log/hotindex-insert-2.log == 

SET DEFAULT_STORAGE_ENGINE='tokudb';

# Establish connection conn1 (user = root)

connect  conn1,localhost,root,,;

connection default;

drop table if exists s;

create table s (a int auto_increment, b int, c int, primary key (a));

# populate table s

# done inserting elements

set tokudb_create_index_online=1;

create index i_a on s(c);

connection conn1;

# starting insert while create index is happening

 == /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)

 - saving '/dev/shm/var/2/log/tokudb.hotindex-insert-2/' to '/dev/shm/var/log/tokudb.hotindex-insert-2/'

Retrying test tokudb.hotindex-insert-2, attempt(2/3)...

worker[2] > Restart  - not started

***Warnings generated in error logs during shutdown after running tests: tokudb.hotindex-insert-0 tokudb.ext_key_1_tokudb tokudb.hotindex-del-slow tokudb.dir_per_db_rename_to_nonexisting_schema tokudb.ext_key_2_tokudb tokudb.hotindex-del-0 tokudb.hotindex-del-fast tokudb.hotindex-insert-2

Attempting backtrace. You can use the following information to find out

tokudb.hotindex-insert-2                 w2 [ retry-pass ]   7815