Re: Optimizing pglz compressor - Mailing list pgsql-hackers

On 2013-03-06 09:36:19 -0600, Merlin Moncure wrote:
> On Wed, Mar 6, 2013 at 8:32 AM, Joachim Wieland <joe@mcknight.de> wrote:
> > On Tue, Mar 5, 2013 at 8:32 AM, Heikki Linnakangas
> > <hlinnakangas@vmware.com> wrote:
> >> With these tweaks, I was able to make pglz-based delta encoding perform
> >> roughly as well as Amit's patch.
> >
> > Out of curiosity, do we know how pglz compares with other algorithms, e.g. lz4 ?
>
> This has been a subject of much recent discussion. It compares very
> poorly, but installing a new compressor tends to be problematic due to
> patent concerns (something which I disagree with but it's there).  All
> that said, Heikki's proposed changes seem to be low risk and quite
> fast.

Imo the licensing part is by far the smaller one. The interesting part
is making a compatible change to the way toast compression works that
supports multiple compression schemes. Afaics nobody has done that work.
After that the choice of to-be-integrated compression schemes needs to
be discussed, sure.