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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Why Cassandra is "space inefficient" compared to MySQL?
Date Tue, 25 May 2010 12:41:04 GMT
That's true.  But fundamentally Cassandra is expected to use more
space than mysql for a few reasons; usually the biggest factor is that
Cassandra has to write out each column name in each row, since column
names are dynamic unlike in mysql where you declare the columns once
for the whole table.

2010/5/25 Peter Schüller <scode@spotify.com>:
>> Could you please tell me why?
>
> There might be pending sstable removals on disk, which won't happen
> until GC or restart. If you just did a bulk insert and checked
> diskspace immediately afterwards, I think this is a possible
> explanation.
>
> (See "Write path" on http://wiki.apache.org/cassandra/ArchitectureInternals)
>
> --
> / Peter Schuller aka scode
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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