Re: Rename dead_tuples to dead_items in vacuumlazy.c

On Wed, Nov 24, 2021 at 2:46 PM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
>
> Attached patch performs polishing within vacuumlazy.c, as follow-up
> work to the refactoring work in Postgres 14. This mainly consists of
> changing references of dead tuples to dead items, which reflects the
> fact that VACUUM no longer deals with TIDs that might point to
> remaining heap tuples with storage -- the TIDs in the array must now
> strictly point to LP_DEAD stub line pointers that remain in the heap,
> following pruning.

+1

> If there are no objections, I'll move on this soon. It's mostly just
> mechanical changes.

The patch renames dead tuples to dead items at some places and to
dead TIDs at some places. For instance, it renames dead tuples to dead
TIDs here:

- * Return the maximum number of dead tuples we can record.
+ * Computes the number of dead TIDs that VACUUM will have to store in the
+ * worst case, where all line pointers are allocated, and all are LP_DEAD

whereas renames to dead items here:

- * extra cost of bsearch(), especially if dead tuples on the heap are
+ * extra cost of bsearch(), especially if dead items on the heap are

I think it's more consistent if we change it to one side. I prefer "dead items".

---
There is one more place where we can rename "dead tuples":

/*
* Allocate the space for dead tuples. Note that this handles parallel
* VACUUM initialization as part of allocating shared memory space used
* for dead_items.
*/

Regards,

--
Masahiko Sawada
EDB: https://www.enterprisedb.com/