I am using the Yii framework for a site that will get a lot of hits (hopefully) because each client will be polling every 250 milliseconds. I want to limit the hits to my database and cache the data, but it needs to be close to real time (about 250 milliseconds). I noticed that the $expire parameter in CCache->set() takes an integer for seconds. I tried to go directly to apc_store() and found the same issue. Memcache seems to also define TTL in seconds.
Does anyone know of a PHP data cache that can work with TTL values less than 1 second or another workaround?
Redis has sub-second expiration. See https://github.com/antirez/redis/issues/169.