System variables are not replicated correctly when using STATEMENT mode, except for the following variables when they are used with session scope:

When MIXED mode is used, the variables in the preceding list, when used with session scope, cause a switch from statement-based to row-based logging. See Section 5.2.4.3, “Mixed Binary Logging Format”.

sql_mode is also replicated except for the NO_DIR_IN_CREATE mode; the slave always preserves its own value for NO_DIR_IN_CREATE, regardless of any changes to this mode on the master. This is true for all replication modes.

However, when mysqlbinlog parses a SET @@sql_mode = value statement, the full value, including NO_DIR_IN_CREATE, is passed to the receiving server. For this reason, replication of such a statement may not be safe when STATEMENT mode is in use.

The storage_engine system variable is not replicated, regardless of the logging mode; this is intended to facilitate replication between different storage engines.

In statement-based replication, session variables are not replicated properly when used in statements that update tables. For example, SET MAX_JOIN_SIZE=1000 followed by INSERT INTO mytable VALUES(@@MAX_JOIN_SIZE) does not insert the same data on the master and the slave. However, this does not apply to the common sequence of SET TIME_ZONE=... followed by INSERT INTO mytable VALUES(CONVERT_TZ(...,...,@@time_zone)).

Replication of session variables is not a problem when row-based replication is being used; with row-based replication, session variables are always replicated safely. See Section 16.1.2, “Replication Formats”.