August 31, 2009, 8:46 am
It’s common to use MySQL as the backend for storing and retrieving what are essentially key/value pairs. I’ve seen this over-and-over when someone needs to maintain a bit of state, session data, counters, small lists, and so on. When MySQL isn’t able to keep up with the volume, we often turn to memcached as a write-thru cache. But there’s a bit of a mis-match at work here. Memcached doesn’t have much in the way of a query language or server-side operations it can perform on the data. In other words, it’s a pretty “dumb” store.
MySQL lies at the other end of the spectrum. It has a rich query language and support for all sorts of server-side processing on the data. So when you combine the two, your app has to know it‚Äôs talking to both and deal with coordinating data changes between the cache and the back-end server…
