Re: [PATCH] Add array_reverse() function

From: Aleksander Alekseev <aleksander(at)timescale(dot)com>
To: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Cc: Ashutosh Bapat <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: [PATCH] Add array_reverse() function
Date: 2024-10-22 13:27:30
Message-ID: CAJ7c6TMuPDMp2KxORDLT9+2Ggu47ye0X_VGyGYB5_F3NM-kb4A@mail.gmail.com
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Hi everyone,

Thanks for the feedback!

> > But it returns the input array as is. I think it should at least make
> > a new copy of input array.
>
> I don't think that's really necessary. We have other functions that
> will return an input value unchanged without copying it. A
> longstanding example is array_larger. Also, this code looks to be
> copied from array_shuffle.

It was indeed copied from array_shuffle().

Makes me wonder if we should have an utility function which would
contain common code for array_shuffle() and array_reverse().
Considering inconveniences such an approach caused in case of common
code for text and bytea types [1] I choose to copy the code and modify
it for the task.

> +
> + /* If the target array is empty, exit fast */
> + if (ndim < 1 || dims[0] < 1)
> + return construct_empty_array(elmtyp);
>
> This is taken care by the caller, at least the ndim < 1 case.

Agree. Here is the corrected patch.

[1]: https://postgr.es/m/CAJ7c6TO3X88dGd8C4Tb-Eq2ZDPz+9mP+KOwdzK_82BEz_cMPZg@mail.gmail.com

--
Best regards,
Aleksander Alekseev

Attachment Content-Type Size
v2-0001-Add-array_reverse-function.patch application/x-patch 7.1 KB

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