Re: [PoC] Improve dead tuple storage for lazy vacuum

On Wed, Dec 20, 2023 at 6:36 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> I've updated the new patch set that incorporated comments I got so
> far. 0007, 0008, and 0012 patches are updates from the v45 patch set.
> In addition to the review comments, I made some changes in tidstore to
> make it independent from heap. Specifically, it uses MaxOffsetNumber
> instead of MaxHeapTuplesPerPage. Now we don't need to include
> htup_details.h. It enlarged MaxBlocktableEntrySize but it's still 272
> bytes.

That's a good idea.

> BTW regarding the previous comment I got before:
>
> > - RT_PTR_ALLOC *slot;
> > + RT_PTR_ALLOC *slot = NULL;
> >
> > We have a macro for invalid pointer because of DSA.
>
> I think that since *slot is a pointer to a RT_PTR_ALLOC it's okay to set NULL.

Ah right, it's the address of the slot.

> I'm going to update RT_DUMP() and RT_DUMP_NODE() codes for the next step.

That could probably use some discussion. A few months ago, I found the
debugging functions only worked when everything else worked. When
things weren't working, I had to rip one of these functions apart so
it only looked at one node. If something is broken, we can't count on
recursion or iteration working, because we won't get that far. I don't
remember how things are in the current patch.

I've finished the node shrinking and addressed some fixme/todo areas
-- can I share these and squash your v46 changes first?