ppolv’s blog

February 4, 2008

Isn’t performance, is scalability

Filed under: random — Tags: , — ppolv @ 8:09 pm

Recently I’ve been reading about cache technologies, memcached in particular. The architecture behind memcached is what catch my attention: its so clear and simple. Beauty .

Then, I reach to this performance comparison between memcached and ehcache (almost a yer old, but I just read it, sorry). At first I was somewhat surprised and to be honest, disappointed. I thought memcached should compare better than that… but … wait…
The author of the article has experience in the word of java caching (actually, he is the maintainer of ehcache), but I think the benchmark isn’t really fair. While the memcached setup is already a distributed one, the ehcache setup don’t. While the memcached setup is ready to hold TERABYTES of data, the ehcache setup don’t.

I don’t say that ehcache can’t be distributed, what i say is that the costs associated with ehcache distribution aren’t represented in the benchmark.

Anyway, the point isn’t about performance, its scalability what matters!. And that’s why you should always read benchmarks carefully.
If my web application isn’t a big, heavy-accessed one (like the intranet applications I’m used to work with) then an entirely in-process caching strategy is fine, and easy to implement and understand too.
But for high-load scenarios, with many web servers involved, benchmarks like this one doesn’t apply.

Update: Unfair Benchmarks of Ehcache vs Memcached another response to the original article.

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