Redis using lots of RAM, steadily increasing until I restart it

Question

I have a simple redis installation and it seems to slowly eat more and more ram at a steady incline until I restart the redis server.

I'm using redis as a caching layer, currently I don't set an expire on my keys as I didn't think that was necessary. I thought redis would drop off old keys or something - though clearly this isn't happening.

Whats the best way of handling this kind of situation, should I set a short expire time on my keys or is there some functionality built into redis to expire old keys to make room for new ones?

Thanks in advanced!

Answer 1

Redis's old tag line is: "A persistent key-value database with built-in net interface written in ANSI-C for Posix systems".

I believe keys are persistent by default. You'll have to set EXPIRE on keys that you actually want to go away after a while. As womble noted, it ain't memcached.

For the command reference: http://redis.io/topics/expire

Answer 2

You can set the maxmemory configuration variable in your redis conf and then set the maxmemory-policy to either allkeys-lru or allkeys->random which will allow keys to be removed from the database and make redis act like a cache. Since you're using it as a cache you can comment out all save lines so redis won't save to disk.

This is probably the easiest way and you won't have to switch to memcached, I suggest the allkeys-lru which will allow any key to be removed with the ones that are least recently used being removed first.