Re: [HACKERS] Custom compression methods

On Sat, Oct 17, 2020 at 11:34 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Tue, Oct 13, 2020 at 10:30 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Mon, Oct 12, 2020 at 7:32 PM Tomas Vondra
> > <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> > >
> > > On Mon, Oct 12, 2020 at 02:28:43PM +0530, Dilip Kumar wrote:
> > > >
> > > >> ...
> > > >
> > > >I have worked on this patch, so as discussed now I am maintaining the
> > > >preserved compression methods using dependency. Still PRESERVE ALL
> > > >syntax is not supported, I will work on that part.
> > > >
> > >
> > > Cool, I'll take a look. What's your opinion on doing it this way? Do you
> > > think it's cleaner / more elegant, or is it something contrary to what
> > > the dependencies are meant to do?
> >
> > I think this looks much cleaner. Moreover, I feel that once we start
> > supporting the custom compression methods then we anyway have to
> > maintain the dependency so using that for finding the preserved
> > compression method is good option.
>
> I have also implemented the next set of patches.
> 0004 -> Provide a way to create custom compression methods
> 0005 -> Extention to implement lz4 as a custom compression method.

In the updated version I have worked on some of the listed items
> A pending list of items:
> 1. Provide support for handling the compression option
> - As discussed up thread I will store the compression option of the
> latest compression method in a new field in pg_atrribute table
> 2. As of now I have kept zlib as the second built-in option and lz4 as
> a custom compression extension. In Offlist discussion with Robert, he
> suggested that we should keep lz4 as the built-in method and we can
> move zlib as an extension because lz4 is faster than zlib so better to
> keep that as the built-in method. So in the next version, I will
> change that. Any different opinion on this?

Done

> 3. Improve the documentation, especially for create_compression_method.
> 4. By default support table compression method for the index.

Done

> 5. Support the PRESERVE ALL option so that we can preserve all
> existing lists of compression methods without providing the whole
> list.

1,3,5 points are still pending.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com