Test main.join_cache_bka_nixbnl is unstable

[Laurynas Biveinis]

On 5.6 trunk:

main.join_cache_bka_nixbnl w1 [ fail ]
        Test ended at 2016-12-09 09:38:46

CURRENT_TEST: main.join_cache_bka_nixbnl
--- /mnt/workspace/percona-server-5.6-trunk/BUILD_TYPE/debug/Host/centos5-64/mysql-test/r/join_cache_bka_nixbnl.result 2016-11-16 15:06:23.956280863 +0300
+++ /mnt/workspace/percona-server-5.6-trunk/BUILD_TYPE/debug/Host/centos5-64/build/mysql-test/var/1/log/join_cache_bka_nixbnl.reject 2016-12-09 17:38:46.193882669 +0300
@@ -2461,7 +2461,7 @@
 GROUP BY field2
 ORDER BY field1;
 id select_type table type possible_keys key key_len ref rows Extra
-1 SIMPLE t1 index col_int_key,col_varchar_key col_varchar_key 7 NULL 3 Using index; Using temporary; Using filesort
+1 SIMPLE t1 index col_int_key,col_varchar_key col_varchar_key 7 NULL 4 Using index; Using temporary; Using filesort
 1 SIMPLE t2 ref col_varchar_key col_varchar_key 3 test.t1.col_varchar_key 1 Using join buffer (Batched Key Access)
 SELECT MIN(t2.col_datetime_key) AS field1,
 t1.col_int_key AS field2

mysqltest: Result content mismatch

[Laurynas Biveinis (laurynas-biveinis)]

     https://github.com/percona/percona-server/pull/1246
     https://github.com/percona/percona-server/pull/1247

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-2217