Ron Mayer wrote:
Grant Allen wrote:
...warehouse...DB2...IBM is seeing typical storage savings in the
40-60% range
Sounds about the same as what compressing file systems claim:
http://opensolaris.org/os/community/zfs/whatis/
"ZFS provides built-in compression. In addition to
reducing space usage by 2-3x, compression also reduces
the amount of I/O by 2-3x. For this reason, enabling
compression actually makes some workloads go faster.
I do note that Netezza got a lot of PR around their
compression release; claiming it doubled performance.
Wonder if they added that at the file system or higher
in the DB.
I just so happen to have access to a Netezza system :-) I'll see if I
can find out.
One other thing I forgot to mention: Compression by the DB trumps
filesystem compression in one very important area - shared_buffers! (or
buffer_cache, bufferpool or whatever your favourite DB calls its working
memory for caching data). Because the data stays compressed in the
block/page when cached by the database in one of its buffers, you get
more bang for you memory buck in many circumstances! Just another angle
to contemplate :-)
Ciao
Fuzzy
:-)
------------------------------------------------
Dazed and confused about technology for 20 years
http://fuzzydata.wordpress.com/
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