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From Peter Schüller <sc...@spotify.com>
Subject Re: Why are writes faster than reads?
Date Tue, 25 May 2010 08:26:10 GMT
> I have seen several off-hand mentions that writes are inherently faster than
> reads. Why is this so?

I believe the primary factor people are referring to is that writes
are faster than reads in terms of disk I/O because writes are
inherently sequential. Writes initially only happen in-memory plus in
a (sequentially written) commit log; when flushed out to an sstable
that is likewise sequential writing.

Reads on the other hand, to the extent that they go down to disk, will
suffer the usual overhead associated with disk seeks.

See http://wiki.apache.org/cassandra/ArchitectureInternals for details.

-- 
/ Peter Schuller aka scode

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