Re: relpages in pg_class

On Fri, Aug 19, 2022 at 11:25:52AM -0700, Peter Geoghegan wrote:
> On Fri, Aug 19, 2022 at 9:40 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Yeah, we use "blocks" and "pages" interchangeably, which is something
> > I don't feel a need to change; but evidently the OP didn't realize that.
> > This is a job for the glossary, perhaps?
>
> I think that they're synonyms that can often (but not always) be used
> interchangeably. I *think* that this understanding is shared by other
> people, though I should check. Here goes:
>
> To me, "block" emphasizes on-disk/relfilenode storage. Something that
> exists at a particular physical offset in a particular file (a
> BlockNumber + relfilenode). On the other hand, the term "page"
> emphasizes the in-memory format, and the indirection provided by the
> bufpage.c slotted page format (i.e. line pointer array indirection).

Yes, I have heard the block-disk, page-memory explanation before.

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