Re: [PATCH] bms_prev_member() can read beyond the end of the array of allocated words - Mailing list pgsql-hackers

> On Aug 14, 2025, at 3:45 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>
> Greg Burd <greg@burd.me> writes:
>> Spoiler alert, I have larger plans[2] for Bitmapset which is why I
>> started down this road to begin with as I wanted to capture the existing
>> API/contract for it before I proposed changes to it.
>
> FWIW, I'd be seriously resistant to simply replacing Bitmapset with
> something like that, as I think the present implementation is about
> right for the planner's uses and complicating it would just slow
> things down.  There may be specific places where a compressed
> implementation could win, though.

Well, I get that and I know I’m battling uphill.  :)  Can’t hurt to
measure and see if there is a benefit or not.  If not, I’ll just propose
a different Sparsemapset (or other reasonable name) in addition to the
existing Bitmapset for the use case that pushed me in this direction.
No reason not to explore options, right?

> Anyway, that's off-topic for the present thread.  I believe it's
> middle-of-the-night in Rowley's time zone, so I was waiting for
> further comment from him before taking any action.

Makes perfect sense, sorry to rush the process.

>             regards, tom lane

best,

-greg