Bug #80402 Delayed replication configuration does not support sub-second precision

Description:
Replication delay can be induced. this is useful for testing.
See: https://dev.mysql.com/doc/refman/5.6/en/replication-delayed.html

I notice that I am unable to configure this with less than sub-second precision.

This is useful for testing application sensitivity to replication delays.

How to repeat:

-- I have an existing replication setup
myuser@myhost [(none)]> change master to master_delay = 0.4;
Query OK, 0 rows affected (0.03 sec)
myuser@myhost [(none)]> show slave status\G
*************************** 1. row ***************************
...
                    SQL_Delay: 0

Note: this does not show 0.4 and I do not get a warning that the input value has been truncated.

Suggested fix:
Please add a warning if you do not accept the value or truncate it.
Ideally add support for this and try to accept the suggested delay value.

Hello Simon,

Thank you for the report.
Observed with 5.6.29 builds.

Thanks,
Umesh