Re: Trivial Fix: use palloc_array/repalloc_array for BufFile file arrays - Mailing list pgsql-hackers

From Masahiko Sawada
Subject Re: Trivial Fix: use palloc_array/repalloc_array for BufFile file arrays
Date
Msg-id CAD21AoDwp1D6-xm3p28RvUJKHcZM+9YtjUzNk38kLitN_Nbq4Q@mail.gmail.com
Whole thread
In response to Re: Trivial Fix: use palloc_array/repalloc_array for BufFile file arrays  (Chao Li <li.evan.chao@gmail.com>)
Responses Re: Trivial Fix: use palloc_array/repalloc_array for BufFile file arrays
List pgsql-hackers
Hi,

On Tue, Mar 3, 2026 at 5:31 PM Chao Li <li.evan.chao@gmail.com> wrote:
>
>
>
> > On Dec 25, 2025, at 11:34, Chao Li <li.evan.chao@gmail.com> wrote:
> >
> >
> >
> >> On Dec 25, 2025, at 11:12, Chao Li <li.evan.chao@gmail.com> wrote:
> >>
> >> Hi Hackers,
> >>
> >> I noticed this error while working on [1].
> >>
> >> In BufFile, the fields is claimed as an array:
> >> ```
> >> struct BufFile
> >> {
> >>    File *files; /* palloc'd array with numFiles entries */
> >> ```
> >>
> >> However, it’s allocated by palloc_object():
> >> ```
> >> file->files = palloc_object(File);
> >> ```
> >>
> >> And reallocated by repalloc():
> >> ```
> >>    file->files = (File *) repalloc(file->files,
> >>        (file->numFiles + 1) * sizeof(File));
> >> ```
> >>
> >> This trivial patch just changes to use palloc_array/repalloc_array, which makes the intent clearer.
> >>
> >> Best regards,
> >> --
> >> Chao Li (Evan)
> >> HighGo Software Co., Ltd.
> >> https://www.highgo.com/
> >>
> >>
> >>
> >>
> >> <v1-0001-Use-palloc_array-repalloc_array-for-BufFile-file-.patch>
> >
> >
> > Sorry for missing the reference of [1]:
> >
> > [1] https://postgr.es/m/aUStrqoOCDRFAq1M@paquier.xyz
> >
> > Best regards,
> > --
> > Chao Li (Evan)
> > HighGo Software Co., Ltd.
> > https://www.highgo.com/
> >
>
> PFA v2:
>  * Rebased
>  * Updated the commit message

I've reviewed the v2 patch and here is a comment:

- file->files = palloc_object(File);
+ file->files = palloc_array(File, 1);

I'm not a fan of this change. This change looks like trying to
distinguish allocated memory by palloc_object() and palloc_array()
even though underlying memory is identical. I'm concerned about this
change creating unnecessary coding conventions.

Regards,

--
Masahiko Sawada
Amazon Web Services: https://aws.amazon.com



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