Question

I’ve been working on a website lately and want to speed up my application.
I want to cache my users’ pages but the pages are dynamic like if someone posts a new feed then the homepage is updated with that new feed. If I cache the homepage for one user and a friend of his posts a new feed I want that cache to be expired and the next time he visits the homepage again the application contacts the database and fetches the new feeds and caches it.

I’m using memcache and PHP and MySQL for my DB.
I have a table called friends, feeds and users.

Will it be efficient to cache every user’s friends and when that user posts a feed, my app fetches his/her friends and caches a notification with their userid so that when those friends log in the app checks at every page if there is a notification to take action (in this case deleting the homepage in the cache).

Regards,
Resul

Answer 1

Profile your application and locate places where you access data that is expensive to fetch (or calculate). Those places are good places to start with memcached, unless you’re doing more writes than reads (where you’d likely have to update the cache more often than you could make use of it).

Caching everything you ever access could well lead to nothing than a quite full memcached that holds mostly data that is rarely accessed (while potentially pushing things out from the cache you actually should cache). In many cases you shouldn’t use memcached as a 1:1 copy of your database in key-value form.