For PostGIS, what mechanism do they use within Postgres to store the low-level (physical, logical) data type? Is there a mechanism that Postgres exposes whereby a third-party extension may create new native Data Types? I know they have CREATE TYPE at the SQL level, but I've been having difficulty locating the lower-level version of this if it exists.

CodePudding user response：

It is well documented how you can extend the PostgreSQL type system in C.