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From gabriele renzi <rff....@gmail.com>
Subject Re: Questions about optmizing interaction with Cassandra
Date Fri, 11 Dec 2009 19:32:27 GMT
2009/12/11 Joseph Bowman <bowman.joseph@gmail.com>:

> Before I start working on something like this, I need to ask, is it even necessary? Would
it really provide a performance increase worth the added complexity and dependence on things
like memcached? I recall someone at Digg gave a presentation where they found that Cassandra
was fast even without implementing a memcached layer. Does anyone on the list have any suggestions/comments
about this idea?

It seems cassandra is pretty fast when reading a small number of
columns, but can be slow for a large number.

Yet, you can cache at the cassandra level.. If you have a spare
gigabyte of ram to host a memcached instance, you can use it for it :)
FWIW, in our current application with 0.4 we implemented in-cassandra
caching, whereas a query that reads many thousands of columns and
takes some time is cached in a separate entry
QueryCache[q]=serializedResult
and we flush it on update.
I don't see why that cant be done by cassandra itself (maybe it's
already done in 0.5) although we will probably keep it all the same:
denormalizing denormalized stuff is fun.


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