Re: What is an item pointer, anyway?

On Fri, Apr 26, 2019 at 4:23 PM Ashwin Agrawal <aagrawal(at)pivotal(dot)io> wrote:
> How about we rename ItemPointerData to TupleIdentifier or ItemIdentifier instead and leave ItemPointer or Item confined to AM term, where item can be tuple, datum or anything else ?

I'm not a fan of that idea, because the reality is that an
ItemPointerData is quite explicitly supposed to be a physiological
identifier (TID) used by heapam, or a similar heap-like access method
such as zheap. This is baked into a number of things.

The limitation that pluggable storage engines have to work in terms of
item pointers is certainly a problem, especially for things like the
Zedstore column store project you're working on. However, I suspect
that that problem is best solved by accommodating other types of
identifiers that don't work like TIDs.

I understand why you've adopted ItemPointerData as a fully-logical
identifier in your prototype, but it's not a great long term solution.

--
Peter Geoghegan