The hintrouter is a router that routes solely based on hints, so it need to be used in conjunction with a filter that provides those hints. An example of such a filter is the namedserverfilter that more aptly should be called regexhintfilter.

In addition it should be possible to specify some default behaviour that is followed if a hint is missing. For instance, you could specify that if a statement lacks a hint, then the statement is routed to some slave, which would mean that the namedserverfilter would then only need to be configured to catch and hint statements that need to be sent to the master. The default behaviour could also be that an error should be returned or that the statement should be routed to all backends. Depending on the context different approaches may the appropritate and thus the behaviour should be configurable.

Together namedserverfilter and hintrouter would provide a very low-overhead solution appropriate in certain situations.