moxi is a memcached proxy with several features which can help keep the memcached contract whole in complicated environments. It also brings several optimizations to memcached deployments, without requiring any changes to the application software using memcached.

Redis is a key-value database. It is similar to memcached but the dataset is not volatile, and values can be strings, exactly like in memcached, but also lists and sets with atomic operations to push/pop elements.

In order to be very fast but at the same time persistent the whole dataset is taken in memory and from time to time and/or when a number of changes to the dataset are performed it is written asynchronously on disk. You may lost the last few queries that is acceptable in many applications but it is as fast as an in memory DB (Redis supports non-blocking master-slave replication in order to solve this problem by redundancy).

This story is part bug hunt, part open-source love-story. The bug was a particularly gnarly, beautiful little bug and I'm going to try to convey some of that to you. But the other half of the story is really the thing here; The Guardian is serious about engaging with the wider technology community - while we work hard to open out our data to the world at large, we also participate by speaking at conferences, sponsoring events, and sometimes in the simplest way of all; contributing code and fixes for the Open Source software that we use.

http://bit.ly/17AazQ

Apache's mod_rewrite provides ways to map values to attributes using the directive RewriteMap. RewriteMap can use flat mappings files, hashed mapping files, internal functions and external rewriting programs. One not well known feature of mod_rewrite is to extend this functionality with internal functions, defined in a separate Apache module. This allows to do complex and time consuming mappings, since the mapping request does not have to be passed through a single communication pipe, as in the case of an external rewrite program.