On Mon, Feb 14, 2022 at 2:19 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > No, at least not unless you plan to reimplement much of the WAL > mechanism. You do need at least an LSN in the right place. > I kinda doubt that you can get away with ignoring checksumming, > either. On the whole, I think you'd be best off to use a standard > page header; the amount you're saving by avoiding that will be > minuscule, and the amount of work you cause for yourself probably > not so much.
It isn't actually necessary for an index AM to use the standard slotted page format to get the benefits that you mention, of course -- whether or not an index AM that uses standard page headers *also* uses slotted pages with standard line pointers is a separate question. For example, GIN posting tree pages don't use standard line pointers, but still have a standard page header (and a generic GIN special area in the opaque space). I agree that it's hard to imagine that opting out of using the standard page header format could ever make much sense. Principally because the restrictions imposed on an index AM that uses the standard page header format are very minimal, while the benefits are substantial. -- Peter Geoghegan
