[postgis-devel] Making SFCGAL mandatory

[Regina Obe]

On Sun, Nov 25, 2018 at 1:12 AM Darafei "Komяpa" Praliaskouski <me at komzpa.net <mailto:me at komzpa.net> > wrote:

 

On Thu, Nov 22, 2018 at 10:57 PM Regina Obe <lr at pcorp.us <mailto:lr at pcorp.us> > wrote:

Not following how that helps getting rid of SFCGAL from the postgis library itself.  The GUC thing doesn't bother me that much and will annoy me even less when 3.0 comes out since we will not have two backends coexisting during upgrade for the life of PostGIS 3 major.

 

It's the fact it's part of postgis library and not a separate library like rtpostgis or postgis_topology that bugs me.

 

Because for packaging you can never cleanly with one compile a separate package for postgis_sfcgal that depends on postgis  and a package for just postgis.

Your postgis package will always be infected with postgis_sfcgal if it were ever to be used as a dependency in the postgis_sfcgal package.

 

1. we remove branching on postgis/sfcgal for same functions. They always go to postgis.
2. if SFCGAL func version adds some value or behavior change, we untangle them by names (not just adding _SFCGAL, but semantic difference) and put sfcgal version into postgis_sfcgal extension.
3. functions like ST_StraightSkeleton skeleton straight to postgis_sfcgal.so.
4. postgis.so has no linkage to sfcgal.
5. postgis_sfcgal.so may have linkage to whatever it needs.
6. if there is a difference in implementation (postgis knows no TIN, sfcgal knows no curve) that goes to each of untangled function's manual entry.

 

Does it look like a plan?

 

 

To me it looks like a plan. No more swappable back-end, distinct function names for cases where functionality overlaps but we want to retain access to both. Much simpler access to SFCGAL, and the ability to build a cleanly separable postgis_sfcgal, works for me.


P.

 

[Regina Obe] 

Paul,

 

Not sure I'm following.

 

I'm okay with the plan, as long as we don't need to rename existing SFCGAL functions where they don't overlap with PostGIS.  So ST_StraightSkeleton, ST_3DIntersection stays named the same, but ST_3DIntersects (implemented by SFCGAL) becomes something like  ST_3DIntersects_SFCGAL?  Or whatever we want to stuff at end.

 

Is that what you are proposing or are you proposing something else.

 

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