I have a news site which receives around 58,000 hits a day for 36,000 articles. Of this 36000 unique stories, 30000 get only 1 hit (majority of which are search engine crawlers) and only 250 stories get over 20 impressions. It is a wastage of memory to cache anything, but these 250 articles.
Currently I am using MySQL Query Cache and xcache for data caching. The table is updated every 5-10 mins, hence Query Cache alone is not much useful. How can I detect frequently visited pages alone and cache the data?