Re: [PATCH] bms_prev_member() can read beyond the end of the array of allocated words
Greg Burd <greg@burd.me>
From: Greg Burd <greg@burd.me>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: David Rowley <dgrowleyml@gmail.com>,
PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-08-14T22:12:08Z
Lists: 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
Commits
-
Add Asserts to validate prevbit values in bms_prev_member
- b4632883d44e 19 (unreleased) landed