On 2021-Nov-24, Alvaro Herrera wrote:
> On 2021-Nov-24, Robert Haas wrote:
>
> > Hmm. I think in my model an item and an item pointer and a line
> > pointer are all the same thing, but a TID is different. When I talk
> > about a TID, I mean the location of an item pointer, not its contents.
> > So a TID is what tells me that I want block 5 and the 4th slot in the
> > item pointer array. The item pointer tells me that the associate tuple
> > is at a certain position in the page and has a certain length.
>
> OK, but you can have item pointers that don't have any item.
> LP_REDIRECT, LP_DEAD, LP_UNUSED item pointers don't have items.
Sorry to reply to myself, but I realized that I forgot to return to the
main point of this thread. If we agree that "an LP_DEAD item pointer
does not point to any item" (an assertion that gives a precise meaning
to both those terms), then a patch that renames "tuples" to "items" is
not doing anything useful IMO, because those two terms are synonyms.
Now maybe Peter doesn't agree with the definitions I suggest, in which
case I would like to know what his definitions are.
--
Álvaro Herrera PostgreSQL Developer — https://www.EnterpriseDB.com/
"How strange it is to find the words "Perl" and "saner" in such close
proximity, with no apparent sense of irony. I doubt that Larry himself
could have managed it." (ncm, http://lwn.net/Articles/174769/)