The slave can connect to the master using SSL if both are 4.1.1 or newer.
MySQL 4.1 and earlier support only replication scenarios involving one master and many slaves.
The syntax for multiple-table
DELETE statements that use table
aliases changed between MySQL 4.0 and 4.1. In MySQL 4.0, you
should use the true table name to refer to any table from which
rows should be deleted:
DELETE test FROM test AS t1, test2 WHERE ...
In MySQL 4.1, you must use the alias:
DELETE t1 FROM test AS t1, test2 WHERE ...
If you use such
statements, the change in syntax means that a 4.0 master cannot
replicate to 4.1 (or higher) slaves.
It is safe to connect servers in a circular master/slave
relationship if you use the
--log-slave-updates option. That
means that you can create a setup such as this:
A -> B -> C -> A
However, many statements do not work correctly in this kind of setup unless your client code is written to take care of the potential problems that can occur from updates that occur in different sequence on different servers.
Server IDs are encoded in binary log events, so server A knows
when an event that it reads was originally created by itself and
does not execute the event (unless server A was started with the
option, which is meaningful only in rare cases). Thus, there are
no infinite loops. This type of circular setup works only if you
perform no conflicting updates between the tables. In other
words, if you insert data in both A and C, you should never
insert a row in A that may have a key that conflicts with a row
inserted in C. You should also not update the same rows on two
servers if the order in which the updates are applied is