[postgis-users] Allowing use of PostGIS EXTENSION w/out raster - how to migrate to no-raster

[Regina Obe]

> So you either specify what you want (including version) or the behavior
depend on how the system postgis was built.
>  Is that considered acceptable behavior for users ?

Nothing has changed strk and nothing will change even by breaking out
postgis_raster.  
Users have always needed to do this if they were relying on a specific
feature of postgis.

If I'm on one of my clients systems, I have no clue what they have installed
or where they got it from.
If they don't have postgis, first thing I do is run

SELECT * FROM pg_available_extensions;

If the default on their system is  noraster, then they have noraster as
default.

If I know they need KNN and they only have 2.1, I know what they have is not
good enough and I have to work around the deficiencies of their version of
postgis
Or demand they upgrade.

Heck we don't even give people the same bill of goods for the same version
of PostGIS

If you have PostGIS >= 2.3 and you are running PostgreSQL 9.5, you don't get
parallel support
If you are running PostGIS >= 2.2 and you have PostgreSQL 9.4, then you
don't get KNN support.

Those are huge features to me why aren't you all  upset about the fact we
call them 2.3.3 or 2.2.5 and they are different.

If I install CREATE EXTENSION postgis;

I don't know what I'm getting unless I do my homework. 

I could be getting version 2.0.0,  2.3.0, 2.4.0 whatever all very different
in functionality.


If I want to be really sure, I specify the VERSION I want and it errors if
it's not there.


> And it confirms users need to know more things (they need to know how
postgis was compiled on the system).

They do not need to know any more than they do now with my solution.

Besides 

SELECT postgis_full_version();

Tells you exactly what version of everything you've got.  It always will
regardless of if raster is a separate extension or not.