Have you looked at PostGIS?
Yeah, I still don't think that's the right way to do it. Storing the
bounding box seems right, but just do that for all the nodes. It's
probably worth looking at the implementation of these functions for,
say, the existing point, box, and polygon datatypes, which have
similar issues.
I intend to change the structure I describe in the future. So if it is not wrong and harmful to the implementation I want to keep that extra info in leaf node entries.
I have read src/backend/access/gist/gistproc.c I am aware of what it does.
According to the documentation, no. It takes a GISTENTRY and returns
a GISTENTRY. But you can extract the relevant key out of there. The
best way to do this, again, is to look at existing examples, like
gist_poly_compress.
Exactly what I am saying. I extract the key out of GISTENTRY of course but that key has to contain a value of some type. And my question is of what type if it is a leaf and of what if it is not a leaf entry?
Thank you for helping.