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help / color / mirror / Atom feedFrom: David Rowley <[email protected]>
To: Greg Burd <[email protected]>
Cc: Tom Lane <[email protected]>
Cc: Chao Li <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Add bms_offset_members() function for bitshifting Bitmapsets
Date: Tue, 21 Apr 2026 13:40:17 +1200
Message-ID: <CAApHDvqPRUqTVU0=Ewm38UKWOV5Ak1mQXg=+L98Mm9CVpyAmLQ@mail.gmail.com> (raw)
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On Tue, 21 Apr 2026 at 02:55, Greg Burd <[email protected]> wrote:
> Were you planning on writing the optimized non-copy version as well? I don't think it is strictly necessary, more a curiosity.
>
> bms_offset_members() -> new bms, might repalloc() replaces existing loops you've found
> bms_shift_members() -> bms is modified in place and fits your new use case a bit better
Not at this stage. The v1 patch did modify the set in-place, so the
code is there if we ever need it. I didn't find any need for it in our
current code. The selective tuple deforming patch I'm working on could
use it, but I doubt it's worth the trouble for 1 caller. It's just for
something that happens during create_plan(), so 1 more allocation in
that code likely isn't going to be noticed.
David
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To: [email protected]
Cc: [email protected], [email protected], [email protected], [email protected], [email protected]
Subject: Re: Add bms_offset_members() function for bitshifting Bitmapsets
In-Reply-To: <CAApHDvqPRUqTVU0=Ewm38UKWOV5Ak1mQXg=+L98Mm9CVpyAmLQ@mail.gmail.com>
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