Re: Missing userland binaries for PostGIS 2.1

Hello Mike,

On 01/24/2016 05:22 PM, Mike Dillon wrote:
> It looks like the apt.postgresql.org <http://apt.postgresql.org> repo
> was recently updated to have PostGIS 2.2 packages. I build a relatively
> popular Docker image for PostGIS, so this was great to see since it's
> something users have been asking to have for some time
> (see https://github.com/appropriate/docker-postgis).

Cool, thanks. And yes, while postgis-2.2 has been released a while ago,
it's not uncommon for it to take a while until it arrives in Debian
testing. In this particular case, 2.2.0 isn't even fully compatible to
2.2.1, so I decided to not upload 2.2.0 to pgapt at all.

> However, it looks like in the process of updating the repo, version 2.1
> of the "postgis" package was removed.

We are providing only exactly one postgis version at a time, so I
wouldn't say it's removed, but upgraded.

Note that an installed postgis-2.1 extension is guaranteed to continue
to work even after an upgrade. We urge you to upgrade the extension
ASAP, though. This is explained in the NEWS file.

> This means that I can no longer
> build an image for PostGIS 2.1 on older Postgres versions that includes
> the PostGIS userland binaries.

We (pgapt) don't currently provide snapshots of the pgapt archive, which
I think is essentially what you'd want for reproducible Docker images.
You currently have to take care of that for yourself, sorry.

> I understand the difficulty of providing both a 2.2 package and a 2.1
> package in the same repo since there is no version number in the package
> name (e.g. "postgis-2.1" and "postgis-2.2")

Not only that, but postgis itself doesn't allow parallel installations
of multiple versions of the extension. Consider 'CREATE EXTENSION postgis;'.

(Granted, we could in theory still provide multiple conflicting
packages. I don't see much value in that, though.)

> so I'm wondering how much
> of a loss it is to no longer have the userland binaries. I personally
> don't use those binaries, so I can't be sure of the impact of simply
> removing them from the Docker image.

To me, removing them from an old image sounds like a bad idea. Also note
that the postgresql-X.Y-scripts only works with the newest version of
the extension. As noted in the NEWS file, you won't be able to create an
old version of the extension after an upgrade.

Why don't you simply upgrade to Postgis 2.2? It's not like the old image
is vanishing.

If you separate code and data containers, as is common in the Docker
world, it might be sensible to provide postgresql-X.Y-postgis-2.1 and
postgresql-X.Y-postgis-2.2 in the code container. That way, users can
upgrade their code container(s) and run it against their data - no
matter which version of the extension their data container is referring to.

Regards

Markus Wanner