Re: New IndexAM API controlling index vacuum strategies

On Wed, Apr 7, 2021 at 12:50 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> Thank you for updating the patches!
>
> I've done the final round of review:

All of the changes from your fixup patch are clear improvements, and
so I'll include them in the final commit. Thanks!

> For 0001 patch, we call PageTruncateLinePointerArray() only in the
> second pass over heap. I think we should note that the second pass is
> called only when we found/made LP_DEAD on the page. That is, if all
> dead tuples have been marked as LP_UNUSED by HOT pruning, the page
> would not be processed by the second pass, resulting in not removing
> LP_UNUSED at the end of line pointer array. So think we can call it in
> this case, i.g., when lpdead_items is 0 and tuples_deleted > 0 in
> lazy_scan_prune().

Maybe it would be beneficial to do that, but I haven't done it in the
version of the patch that I just pushed. We have run out of time to
consider calling PageTruncateLinePointerArray() in more places. I
think that the most important thing is that we have *some* protection
against line pointer bloat.

--
Peter Geoghegan