Ken Tanzer <ken.tanzer@xxxxxxxxx> writes: > Presumably the complete command would let you figure out it's a rename, and > the old and new tables. But I found this message ( > https://postgrespro.com/list/thread-id/1561932) stating that a > pg_ddl_command could only be processed in C, not in a procedural language. > I'm wondering if that just hasn't been implemented yet and is likely to > change at some point, or if there is some kind of inherent limitation > involved. That's basically the missing infrastructure I referred to. The parse tree data structures are reasonably well-documented internally (look under src/include/nodes/), but there's not a lot of mechanism in place for displaying them to high-level code. We do have decent support for reverse-compiling DML statements (select/insert/update/delete), but not for utility commands which is what you're interested in. There's no inherent reason we couldn't get there, it's just that it'd be a lot of work to get to reasonable coverage, and probably a lot of code to maintain going forward. It looks like src/test/modules/test_ddl_deparse/ contains the beginnings of a facility of this sort ... but it's only test code and doesn't necessarily have anybody's blessing as to being a good basis for moving forward. regards, tom lane
