[postgis-devel] Much slower processing on GEOS 3.9.0 versus 3.8.0 for geodesic area calculation

[Justin Pryzby]

On Mon, Apr 26, 2021 at 12:03:39PM +0200, Marco Boeringa wrote:
> The postgis_full_version results for these setups are:
> 
> - POSTGRESQL 13.2 / POSTGIS 3.1.1 / GEOS 3.8.0:
> 
> PostGIS version: POSTGIS="3.1.1 aaf4c79" [EXTENSION] PGSQL="130"
> GEOS="3.8.0-CAPI-1.13.1 " PROJ="6.3.1" LIBXML="2.9.10" LIBJSON="0.13.1"
> LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)"
> 
>  - POSTGRESQL 13.2 / POSTGIS 3.1.1 / GEOS 3.9.0:
> 
> PostGIS version: POSTGIS="3.1.1 aaf4c79" [EXTENSION] PGSQL="130"
> GEOS="3.9.0-CAPI-1.16.2" PROJ="6.3.1" LIBXML="2.9.10" LIBJSON="0.13.1"
> LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)"
> 
> I am not entirely sure why 'postgis_full_version' is showing 'PGSQL="130"'
> instead of 'PGSQL="132"', as I am definitely on 13.2, 'SELECT version()'
> returns:
> 
> PostgreSQL 13.2 (Ubuntu 13.2-1.pgdg20.04+1) on x86_64-pc-linux-gnu, compiled
> by gcc (Ubuntu 9.3.0-17ubuntu1~20.04) 9.3.0, 64-bit

It looks like that's trying to return the major version, where 9.6 => 96 and 10
=> 100.

I think this may be a better way - pg_control_system is available since v9.6
| SELECT pg_control_version FROM pg_control_system();

Note that uses an extra digit.  Maybe the next postgis version would switch to
using postgres own machine-readable format for "major versions", with v14 => 1400

-- 
Justin