Re: [PoC] Improve dead tuple storage for lazy vacuum

Hi,

On 2022-07-08 11:09:44 +0900, Masahiko Sawada wrote:
> I think that at this stage it's better to define the design first. For
> example, key size and value size, and these sizes are fixed or can be
> set the arbitary size? Given the use case of buffer mapping, we would
> need a wider key to store RelFileNode, ForkNumber, and BlockNumber. On
> the other hand, limiting the key size is 64 bit integer makes the
> logic simple, and possibly it could still be used in buffer mapping
> cases by using a tree of a tree. For value size, if we support
> different value sizes specified by the user, we can either embed
> multiple values in the leaf node (called Multi-value leaves in ART
> paper) or introduce a leaf node that stores one value (called
> Single-value leaves).

FWIW, I think the best path forward would be to do something similar to the
simplehash.h approach, so it can be customized to the specific user.

Greetings,

Andres Freund