Comment 9 for bug 1441908

Upstream 5.7.9 does NOT seem to be affected in the same way, it starts fast enough:

2015-11-19T11:44:17.462034Z 0 [Note] InnoDB: Highest supported file format is Barracuda.
2015-11-19T11:44:19.136225Z 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2015-11-19T11:44:19.136346Z 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2015-11-19T11:44:19.454677Z 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2015-11-19T11:44:19.462071Z 0 [Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
2015-11-19T11:44:19.462110Z 0 [Note] InnoDB: 32 non-redo rollback segment(s) are active.
2015-11-19T11:44:19.463178Z 0 [Note] InnoDB: Waiting for purge to start
2015-11-19T11:44:19.513508Z 0 [Note] InnoDB: 5.7.9 started; log sequence number 352871785
2015-11-19T11:44:19.514378Z 0 [Note] InnoDB: not started
2015-11-19T11:44:19.514467Z 0 [Note] Plugin 'FEDERATED' is disabled.
2015-11-19T11:44:19.518168Z 0 [Note] InnoDB: Loading buffer pool(s) from /home/openxs/dbs/5.7/data/ib_buffer_pool
2015-11-19T11:44:19.518421Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without certificate and private key
2015-11-19T11:44:19.518937Z 0 [Note] Server hostname (bind-address): '*'; port: 3306
2015-11-19T11:44:19.518984Z 0 [Note] IPv6 is available.
2015-11-19T11:44:19.519002Z 0 [Note] - '::' resolves to '::';
2015-11-19T11:44:19.519013Z 0 [Note] Server socket created on IP: '::'.
2015-11-19T11:44:19.519291Z 0 [Note] InnoDB: Buffer pool(s) load completed at 151119 13:44:19
2015-11-19T11:44:19.636511Z 0 [Note] Event Scheduler: Loaded 0 events
2015-11-19T11:44:19.636793Z 0 [Note] /home/openxs/dbs/5.7/bin/mysqld: ready for connections.
Version: '5.7.9' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL)

The delay is less than 2 seconds for this command:

 bin/mysqld_safe --no-defaults --table_definition_cache=50000 --table_open_cache=10000 &

and I do have 50K tables:

mysql> select version(), count(*) from information_schema.tables;
+-----------+----------+
| version() | count(*) |
+-----------+----------+
| 5.7.9 | 50282 |
+-----------+----------+
1 row in set (0,52 sec)

mysql> show variables like 'table_d%';
+------------------------+-------+
| Variable_name | Value |
+------------------------+-------+
| table_definition_cache | 50000 |
+------------------------+-------+
1 row in set (0,00 sec)

...
*************************** 229. row ***************************
  Type: performance_schema
  Name: performance_schema.memory
Status: 163510080
229 rows in set (0,03 sec)