Friday, May 26, 2006


Long time since I last wrote here. Life has been busy of course!

In the meantime I have finished a project and am going to move on to another in a few days of time. Did quite a lot of research on caching algorithms. And was simply amazed at how much the industry is behind with respect to caching strategies. Solaris 10 still uses a 2-handed clock algorithm! Linux is still at LRU with page ageing. Oracle still uses multiple LRU queues in its buffer cache. Hitachi Tagmastore - arguably the best cache-based array solution still uses LRU algorithm for caching! The surprise was PostgreSQL which moved on to ARC, only to discover that it was patented by IBM! Poor guys had to go back to 2Q after dumping ARC.

But things are improving. A patch came in for Linux with a generalized page-replacement framework implementing not one but four different caching strategies! But as they say - you can't have all the good things - it got rejected on the grounds of injecting maintainability and stability issues in the Linux kernel. But there's still hope - Clock-PRO algorithm is still being considered for the current page-replacement scheme in the Linux kernel. Hopefully, things will improve for the better.