Memcached - Pros and Cons

We have a website at swalif.com which is like a news website based on forums. We are currently using a mysql database and things are getting slow. We decided to go with the Sphinx Search Server to speedup things and its been going quiet well.

Recently we heard of something called 'memcached' and just going through it we think we should look into it before moving to a search server completely.

My开发者_Go百科 question is what are the pros and cons of using 'memcached' as it is a fairly new topic to us.

Thanking you

I just got my site set up with memcached a couple months back and it's amazing. The pros are rather obvious. It can be used to cache information that is, perhaps difficult to gather. The best example is an expensive mysql query. Check your slow query log, that would be a good starting point for things to parts to target. I had this one main page that took 2.5 seconds to echo from the server (horrible, I know). I had thought about changing the way it was written and it would have been very complicated. I put in memcached on the "difficult" parts of that page and now it's down to 0.001 seconds to parse. It's just amazing.

There is one main con that I've run into. If you update your content, you have to delete all associated keys related to that new content so that your front end will refetch the data and cache the new data. If not, you get stale content. I have tens of thousands of entries in my memcached and it's difficult to delete all the appropriate ones. If you don't, you'll get old content. One solution is to just set your key expiration duration to something short (24 hours). If you do that, you know that your site will reflect the newest content, at worst, 24 hours after a change. So if you can live with that, this problem is rather moot.

Bottom line, it's one of the best tools I've ever seen. It took me less than a day to install it on the lions share of my rather big site and the impact was tremendous.