Re: HOT readme missing documentation on summarizing index handling

On Fri, 7 Jul 2023 at 00:14, Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com> wrote:
>
> Yeah, README.HOT should have been updated, and I see no reason not to
> backpatch this to v16. Barring objections, I'll do that tomorrow.
>
> I have two suggesting regarding the README.HOT changes:
>
> 1) I'm not entirely sure it's very clear what "referential integrity of
> indexes across tuple updates" actually means. I'm afraid "referential
> integrity" may lead readers to think about foreign keys. Maybe it'd be
> better to explain this is about having index pointers to the new tuple
> version, etc.
>
> 2) Wouldn't it be good to make it a bit more explicit we now have three
> "levels" of HOT:
>
> (a) no indexes need update
> (b) update only summarizing indexes
> (c) update all indexes
>
> The original text was really about on/off, and I'm not quite sure the
> part about "exception" makes this very clear.

Agreed on both points. Attached an updated version which incorporates
your points.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech)