rocksdb.mariadb_port_fixes fails in BB about once a week

rocksdb.mariadb_port_fixes 'write_prepared' w3 [ fail ]

        Test ended at 2019-08-05 12:56:38

CURRENT_TEST: rocksdb.mariadb_port_fixes

--- /usr/share/mysql-test/plugin/rocksdb/rocksdb/r/mariadb_port_fixes.result	2019-08-05 10:44:46.000000000 +0000

+++ /dev/shm/var/3/log/mariadb_port_fixes.reject	2019-08-05 12:56:38.095102414 +0000

@@ -52,7 +52,7 @@

 insert into t2 values (1,1,1),(2,2,2);

 explain select a from t2 where a <'zzz';

 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

-1	SIMPLE	t2	range	a	a	32	NULL	#	Using where

+1	SIMPLE	t2	ALL	a	NULL	NULL	NULL	#	Using where

 drop table t1,t2;

 set global rocksdb_strict_collation_check=@tmp_rscc;

 #

mysqltest: Result length mismatch

 - saving '/dev/shm/var/3/log/rocksdb.mariadb_port_fixes-write_prepared/' to '/dev/shm/var/log/rocksdb.mariadb_port_fixes-write_prepared/'

Retrying test rocksdb.mariadb_port_fixes, attempt(2/3)...

worker[3] > Restart  - not started

federated.federated_bug_13118 'X'        w4 [ pass ]    118

federated.federated_bug_25714 'X'        w4 [ skipped ]  Need bug25714 test program

rocksdb.mariadb_port_fixes 'write_prepared' w3 [ retry-pass ]    231