Re: Add bms_offset_members() function for bitshifting Bitmapsets

From: Peter Eisentraut <peter(at)eisentraut(dot)org>
To: David Rowley <dgrowleyml(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, PostgreSQL Developers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Add bms_offset_members() function for bitshifting Bitmapsets
Date: 2026-04-15 19:17:12
Message-ID: ee61a3c6-5d99-4b3e-87de-4a01eed449b2@eisentraut.org
Views: Whole Thread | Raw Message | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 15.04.26 04:33, David Rowley wrote:
> On Wed, 15 Apr 2026 at 14:30, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>
>> David Rowley <dgrowleyml(at)gmail(dot)com> writes:
>>> I'd not considered surprise-prone as an aspect. I understand we have
>>> bms_join and bms_union, which do the same thing if you only care about
>>> the value of the result and not what happens to the inputs.
>>
>> Sure, but bms_join is an optional optimization of the far safer
>> bms_union operation. It bothers me to create the optimized case
>> but not the base case.
>
> Hmm, yeah. That seems like a good argument for making a new set. I'll
> go make it so.

Depending on what you end up doing, maybe a sprinkling of pg_nodiscard
could be appropriate.

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Bruce Momjian 2026-04-15 19:27:06 Re: First draft of PG 19 release notes
Previous Message Peter Eisentraut 2026-04-15 19:12:51 Re: Reduce build times of pg_trgm GIN indexes