[OSM-dev] Compression types in PBF Format

[Anthony]

On Wed, Dec 1, 2010 at 10:47 AM, Stefan de Konink <stefan at konink.de> wrote:
> On Wed, 1 Dec 2010, Anthony wrote:
>
>>> Yeah, but your lead basically shows we are talking about more than 10%...
>>
>> Yeah, probably, but at the expense of more complicated code, greater
>> memory usage, etc.
>
> The hole process is IO-bound... memory is used anyway to overcome the IO
> issues...

Not in an embedded system, which is where a small difference like 10%
is going to matter.

>> I'm interested now in seeing how the full history compression goes,
>> though.  If it can achieve 70, 80, 90% on top of zlib, then it might
>> be worth embedding the compression as opposed to just using it for
>> transfer over the Internet.
>
> The dictionary is compressed per block, so it greatly depends if the trick
> works.

32 megs is a lot better than 900K, though.  900K is how much zlib uses, right?