If this optional parameter is defined, it will be used to
replace a record in the session database. If it is not defined,
DeleteQuery and AddQuery will be used instead. By default, ReplaceQuery is
not defined. %1 by the NAS IP address, %2 by the NAS-Port, %3 by the SQL
quoted Acct-Session-Id.
This
option is provided because some databases (such as MySQL) offer a more
efficient way to ‘insert or replace’ queries. Special formatting
characters may be used.