On Mon, Apr 15, 2019 at 9:16 AM Ashwin Agrawal <aagra...@pivotal.io> wrote: > Would like to know more specifics on this Peter. We may be having different > context on hybrid row/column design.
I'm confused about how close your idea of a TID is to the traditional definition from heapam (and even zheap). If it's a purely logical identifier, then why would it have two components like a TID? Is that just a short-term convenience or something? > Yes, the plan to optimize out TID space per datum, either by prefix > compression or delta compression or some other trick. It would be easier to do this if you knew for sure that the TID behaves almost the same as a bigserial column -- a purely logical monotonically increasing identifier. That's why I'm interested in what exactly you mean by TID, the stability of a TID value, etc. If a leaf page almost always stores a range covering no more than few hundred contiguous logical values, you can justify aggressively compressing the representation in the B-Tree entries. Compression would still be based on prefix compression, but the representation itself can be specialized. -- Peter Geoghegan
