| From: | Nathan Bossart <nathandbossart(at)gmail(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)anarazel(dot)de> |
| Cc: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Mats Kindahl <mats(at)timescale(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)lists(dot)postgresql(dot)org |
| Subject: | Re: glibc qsort() vulnerability |
| Date: | 2024-02-07 22:21:24 |
| Message-ID: | 20240207222124.GA382832@nathanxps13 |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Feb 07, 2024 at 01:48:57PM -0800, Andres Freund wrote:
> Now, in most cases this won't matter, the sorting isn't performance
> critical. But I don't think it's a good idea to standardize on a generally
> slower pattern.
>
> Not that that's a good test, but I did quickly benchmark [1] this with
> intarray. There's about a 10% difference in performance between using the
> existing compASC() and one using
> return (int64) *(const int32 *) a - (int64) *(const int32 *) b;
>
>
> Perhaps we could have a central helper for this somewhere?
Maybe said helper could use __builtin_sub_overflow() and fall back to the
slow "if" version only if absolutely necessary. The assembly for that
looks encouraging, but I still need to actually test it...
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Peter Smith | 2024-02-07 23:04:16 | Re: Question about behavior of deletes with REPLICA IDENTITY NOTHING |
| Previous Message | James Coleman | 2024-02-07 22:03:43 | Re: Question about behavior of deletes with REPLICA IDENTITY NOTHING |