User agent caching

[scottreed]

So, we noticed today that our database had about 2.5 million user agents cached, which seems to be creating some performance issues. What is the recommended approach for this? Should a periodic flush be scheduled as opposed to turning off the cache altogether?

[kamermans]

If you are using MongoDB, you can use a fixed-length table (circular log) which will purge UAs as they begin to fill up the server. Otherwise, there will need to be some sort of pruning. 2.5M is a LOT of user agents, I haven't seen more that a few hundred thousand or so in a cache table - are you using SimpleDesktop (see TeraWurflConfig.php)? This will dramatically reduce the number of cached desktop user agents. Also, are you using version 2.1.3? If you would like to send me a compressed dump of your cache table's user agents, I can analyze them and see if I can find a way to eliminate a bulk of them by tweaking the code.