Re: Compression of full-page-writes

On Thu, Oct 24, 2013 at 11:07:38AM -0400, Robert Haas wrote:
> On Mon, Oct 21, 2013 at 11:52 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> > So, our consensus is to introduce the hooks for FPW compression so that
> > users can freely select their own best compression algorithm?
> > Also, probably we need to implement at least one compression contrib module
> > using that hook, maybe it's based on pglz or snappy.
>
> I don't favor making this pluggable. I think we should pick snappy or
> lz4 (or something else), put it in the tree, and use it.
>
Hi,

My vote would be for lz4 since it has faster single thread compression
and decompression speeds with the decompression speed being almost 2X
snappy's decompression speed. The both are BSD licensed so that is not
an issue. The base code for lz4 is c and it is c++ for snappy. There
is also a HC (high-compression) varient for lz4 that pushes its compression
rate to about the same as zlib (-1) which uses the same decompressor which
can provide data even faster due to better compression. Some more real
world tests would be useful, which is really where being pluggable would
help.

Regards,
Ken