Re: Remove HeapTuple and Buffer dependency for predicate locking functions

Hi,

On 2019-07-31 09:57:58 +1200, Thomas Munro wrote:
> On Tue, Jun 25, 2019 at 6:02 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> > Hm. I wonder if we somehow ought to generalize the granularity scheme
> > for predicate locks to not be tuple/page/relation. But even if, that's
> > probably a separate patch.
>
> What do you have in mind?

My concern is that continuing to inferring the granularity levels from
the tid doesn't seem like a great path forward. An AMs use of tids might
not necessarily be very amenable to that, if the mapping isn't actually
block based.

> Perhaps you just want to give those things different labels, "TID
> range" instead of page, for the benefit of "logical" TID users?
> Perhaps you want to permit more levels? That seems premature as long
> as TIDs are defined in terms of blocks and offsets, so this stuff is
> reflected all over the source tree...

I'm mostly wondering if the different levels shouldn't be computed
outside of predicate.c.

Greetings,

Andres Freund