MySQL 5.7 Reference Manual
MySQL 5.7 Release Notes
By default, master and slave servers assume that they are in the
same time zone. If you are replicating between servers in
different time zones, the time zone must be set on both master
and slave. Otherwise, statements depending on the local time on
the master are not replicated properly, such as statements that
use the NOW() or
FROM_UNIXTIME() functions.
Verify that your combination of settings for the system time
zone (system_time_zone), server
current time zone (the global value of
time_zone), and per-session
time zones (the session value of
time_zone) on the master and
slave is producing the correct results. In particular, if the
time_zone system variable is
set to the value SYSTEM, indicating that the
server time zone is the same as the system time zone, this can
cause the master and slave to apply different time zones. For
example, a master could write the following statement in the
binary log:
SET @@session.time_zone='SYSTEM';
If this master and its slave have a different setting for their
system time zones, this statement can produce unexpected results
on the slave, even if the slave's global
time_zone value has been set to
match the master's. For an explanation of MySQL Server's time
zone settings, and how to change them, see
MySQL Server Time Zone Support.
See also Section 4.1.15, “Replication and System Functions”.