Sphere based calculations for geography don't appear to be faster?

[Regina Obe]

This does not surprise me.  I think Paul wrote that note 15 years ago and even then I don't recall it making a significant difference and back then we weren't even using geographylib and think we are now even for sphere.
We should probably take that not out of the docs.

Paul you have anything to say about the below? Does it make a difference maybe if you have a narly multipolygon with 5,000,000 points?

> -----Original Message-----
> From: Marco Boeringa 
> Subject: Sphere based calculations for geography don't appear to be faster?
> 
> Hi,
> 
> After the PostGIS 3.4.3 release, that fixed an issue with sphere based
> calculations for geography type, I decided to run a quick test to see if sphere
> based calculations would give a performance benefit for my workflow. Due to
> the existing bug, I had been using spheroid based calculations exclusively up to
> now.
> 
> According to the Help (https://postgis.net/docs/ST_Area.html), the sphere
> based calculations should be faster. However, looking at the timings listed
> below, it appears there is no significant difference?
> 
> SQL used:
> 
> DROP MATERIALIZED VIEW IF EXISTS atest;
> CREATE MATERIALIZED VIEW atest AS SELECT
> ST_AREA(way::geography,true/false) FROM planet_osm_polygon
> 
> The test data was the Geofabrik Italy extract, and used the polygon table of an
> osm2pgsql import containing +/- 19M records, containing polygons of varying
> sizes up to country size. The tests were run on a local dedicated system with
> plenty of IO and CPU.
> 
> Marco
> 
> *** SPHEROID ***:
> Start time    2024-10-01 08:07:05.984
> Finish time    2024-10-01 08:07:15.248
> 
> Start time    2024-10-01 08:08:13.881
> Finish time    2024-10-01 08:08:24.362
> 
> Start time    2024-10-01 08:08:42.772
> Finish time    2024-10-01 08:08:51.998
> 
> Start time    2024-10-01 08:09:16.137
> Finish time    2024-10-01 08:09:26.484
> 
> *** SPHERE ***
> Start time    2024-10-01 08:10:35.261
> Finish time    2024-10-01 08:10:45.846
> 
> Start time    2024-10-01 08:11:05.856
> Finish time    2024-10-01 08:11:16.110
> 
> Start time    2024-10-01 08:11:35.278
> Finish time    2024-10-01 08:11:44.499
> 
> Start time    2024-10-01 08:12:18.769
> Finish time    2024-10-01 08:12:29.020