Re: PostgreSQL 8.4 performance tuning questions

On 8/4/09 8:30 AM, "Alvaro Herrera" <alvherre(at)commandprompt(dot)com> wrote:

> Merlin Moncure escribió:
>> On Mon, Aug 3, 2009 at 5:30 PM, PFC<lists(at)peufeu(dot)com> wrote:
>>>
>>>> lzo is much, much, (much) faster than zlib.  Note, I've tried several
>>>
>>> decompression speed is even more awesome...
>>>
>>>> times to contact the author to get clarification on licensing terms
>>>> and have been unable to get a response.
>>>
>>> lzop and the LZO library are distributed under the terms of the GNU General
>>> Public License (GPL).
>>> source : http://www.lzop.org/lzop_man.php
>>
>> yeah...I have another project I'm working on that is closed source,
>> plus I was curious if something could be worked out for pg...lzo seems
>> ideal for database usage.
>
> I think this was already discussed here. It turns out that a specific
> exception for PG wouldn't be acceptable because of the multiple
> commercial derivates. LZO would have to become BSD, which presumably
> the author just doesn't want to do.
>
> Maybe we could have a --enable-lzo switch similar to what we do with
> readline. Of course, a non-LZO-enabled build would not be able to read
> a dump from such a build. (We could also consider LZO for TOAST
> compression).
>

There are a handful of other compression algorithms very similar to LZO in
performance / compression level under various licenses.

LZO is just the best known and most widely used.

http://www.fastlz.org/ (MIT)
http://www.quicklz.com/ (GPL again)
http://oldhome.schmorp.de/marc/liblzf.html (BSD -ish)

ZFS uses LZJB (CDDL) source code here:
http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/os/
compress.c
(a good read for one of the most simple LZ compression algorithms in terms
of lines of code -- about 100 lines)

Fastlz, with its MIT license, is probably the most obvious choice.

> --
> Alvaro Herrera http://www.CommandPrompt.com/
> PostgreSQL Replication, Consulting, Custom Development, 24x7 support
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