On Fri, May 23, 2025 at 4:29 PM Tomas Vondra <tomas@vondra.me> wrote:
Also, Alvaro seemed to think TAM is the way to go, and in order to keep the OLTP performance he suggested to use both heap and VCI at the same time, in different "forks". I'm not sure how would that work, or if we can already do that - AFAIK we can't, because ForkNumber does not allow adding custom forks. We'd have to relax that, or invent some sort of federated TAM (that just multiplexes it to two TAMs). Maybe.
But it's not like the IAM approach doesn't need to do this. The first patch had to add stuff to a lot of random places to make this work. And some of the places touch stuff that we don't expect indexes to worry about, like ALTER TABLE, etc.
I suspect another option would be to handle this with table inheritance: have one child that is heap-based, a second that's VCI, and a background job to move data from heap to VCI (and vice-versa for updates and maybe deletes).
Note that you could actually implement all that in user-space. Personally I'd much rather have a way to do pure VCI / column-store sooner and manage it myself than have to wait another release (or more) to get a complete solution...
