Re: Vacuum: allow usage of more than 1GB of work mem

On Fri, Apr 6, 2018 at 4:25 PM, Claudio Freire <klaussfreire(at)gmail(dot)com> wrote:
>> True all that. My point is that the multi-segmented array isn't all that
>> simple and proven, compared to an also straightforward B-tree. It's pretty
>> similar to a B-tree, actually, except that it has exactly two levels, and
>> the node (= segment) sizes grow exponentially. I'd rather go with a true
>> B-tree, than something homegrown that resembles a B-tree, but not quite.
>
> I disagree.

Yeah, me too. I think a segmented array is a lot simpler than a
home-grown btree. I wrote a home-grown btree that ended up becoming
src/backend/utils/mmgr/freepage.c and it took me a long time to get
rid of all the bugs. Heikki is almost certainly better at coding up a
bug-free btree than I am, but a segmented array is a dead simple data
structure, or should be if done properly, and a btree is not.

--
Robert Haas
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