Smart (?) Database Cache

Question

I\'ve seen several database cache engines, all of them are pretty dumb (i.e.: keep this query cached for X minutes) and require that you manually delete the whole c

Answer 1

This is related to the problem of session splitting when working with multiple databases in a master-slave configuration. Basically, a similar set of regular expressions are used to determine which tables (or even which rows) are being read from or written to. The system keeps track of which tables were written to and when, and when a read to one of those tables comes up, it's routed to the master. If a query is reading from a table whose data needn't be up-to-the-second accurate, then it's routed to the slave. Generally, information only really needs to be current when it's something a user changed themselves (i.e., editing a user's profile).

They talk about this a good bit in the O'Reilly book High Performance MySQL. I used it quite a bit when developing a system for handling session splits back in the day.