Re: preserving db/ts/relfilenode OIDs across pg_upgrade (was Re: storing an explicit nonce)

On Tue, Jan 18, 2022 at 12:35 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Tue, Dec 14, 2021 at 1:21 PM Shruthi Gowda <gowdashru(at)gmail(dot)com> wrote:
> > Thanks, Robert for the updated version. I reviewed the changes and it
> > looks fine.
> > I also tested the patch. The patch works as expected.
>
> Thanks.
>
> > > - I adjusted the function header comment for heap_create. Your
> > > proposed comment seemed like it was pretty detailed but not 100%
> > > correct. It also made one of the lines kind of long because you didn't
> > > wrap the text in the surrounding style. I decided to make it simpler
> > > and shorter instead of longer still and 100% correct.
> >
> > The comment update looks fine. However, I still feel it would be good to
> > mention on which (rare) circumstance a valid relfilenode can get passed.
>
> In general, I think it's the job of a function parameter comment to
> describe what the parameter does, not how the callers actually use it.
> One problem with describing the latter is that, if someone later adds
> another caller, there is a pretty good chance that they won't notice
> that the comment needs to be changed. More fundamentally, the
> parameter function comments should be like an instruction manual for
> how to use the function. If you are trying to figure out how to use
> this function, it is not helpful to know that "most callers like to
> pass false" for this parameter. What you need to know is what value
> your new call site should pass, and knowing what "most callers" do or
> that something is "rare" doesn't really help. If we want to make this
> comment more detailed, we should approach it from the point of view of
> explaining how it ought to be set.

It's clear now. Thanks for clarifying.

> I've committed the v8-0001 patch you attached. I'll write separately
> about v8-0002.

Sure. Thank you.