Re: [WIP] [B-Tree] Retail IndexTuple deletion

On Mon, Jul 2, 2018 at 7:29 AM, Andrey V. Lepikhov
<a(dot)lepikhov(at)postgrespro(dot)ru> wrote:
> In the new version the patch [1] was used in cooperation with 'retail
> indextuple deletion' and 'quick vacuum strategy' patches (see
> '0004-Retail-IndexTuple-Deletion-with-TID-sorting-in-leaf-.patch'.

Cool.

I'm going to post a revised version of the unique key patch soon. I've
found that it's slightly faster to use DESC ordering for the implicit
heap TID attribute. Doing so also restores the old user-visible
behavior for DROP dependency management, which allows me to remove all
changes to the regression test output

> Execution time of last "VACUUM test;" command on my notebook was:
>
> with bulk deletion: 1.6 s;
> with Quick Vacuum Strategy: 5.2 s;
> with Quick Vacuum Strategy & TID sorting: 0.6 s.

I'm glad that you looked into this. You could make this faster still,
by actually passing the lowest heap TID in the list of TIDs to kill to
_bt_search() and _bt_binsrch(). You might have to work through several
extra B-Tree leaf pages per bttargetdelete() call without this (you'll
move right multiple times within bttargetdelete()).

--
Peter Geoghegan