[postgis-users] [postgis-devel] Allowing use of PostGIS EXTENSION w/out raster

[Regina Obe]

> The proposals are:

 1) Move raster to its own extension "postgis_raster"
    See https://trac.osgeo.org/postgis/ticket/3888

 2) Provide two versions of extension "postgis"
    See https://trac.osgeo.org/postgis/ticket/3890

Implementation of the first proposal is ready for test in a git branch (https://git.osgeo.org/gogs/postgis/postgis/pulls/18)

For each proposal we should consider:

 - How users can enable/disable raster
   proposal 1: CREATE/DROP EXTENSION postgis_raster
   proposal 2: ALTER EXTENSION postgis UPDATE TO "<x>"/"<x>noraster"

 >  - How users can upgrade from older versions of postgis
  > p1: ALTER EXTENSION postgis UPDATE; CREATE EXTENSION postgis_raster FROM unpackaged;

The problem with this is you can't install postgis_raster from unpackaged without first upgrading your raster by running rtpostgis_upgrade.sql

Running functions that install c libs is not allowed on Amazon RDS (and I suspect other Dbaas as well), so Amazon RDS folks will be screwed by this if they need raster.
Also since as I recall you don't uninstall raster, there will be dangling raster functions that rely on a previous PostGIS.  Extremely painful if you ever need to upgrade your db.

 >   p2: ALTER EXTENSION postgis UPDATE; -- what if default version is w/out raster ?

If the default is without raster and you have a postgis with raster from previous.  It's going to drop all raster functions from your db.
If you have tables that rely on raster the upgrade will then gracefull fail telling you your db relies on raster.

So you would then have to change your upgrade statement to

ALTER EXTENSION postgis UPDATE "2.5.0";


Thanks,
Regina