Feedback-ID: ic6394509:Fastmail
MIME-Version: 1.0
Date: Wed, 14 Aug 2024 17:39:32 +0200
From: "Joel Jacobson" <joel@compiler.org>
To: "David Fetter" <david@fetter.org>
Cc: "Aleksander Alekseev" <aleksander@timescale.com>,
 pgsql-hackers@lists.postgresql.org
Message-Id: <7b4236b7-079d-4f10-b2aa-efc83955f6df@app.fastmail.com>
In-Reply-To: <ZrzCpy36C9w/X87C@fetter.org>
References: 
 <CAJ7c6TPtOp6+kFX5QX3fH1SVr7v65uHr-7yEJ=GMGQi5uhGtcA@mail.gmail.com>
 <7882ebcf-4f1f-4f57-afeb-e1301dd6c9d3@app.fastmail.com>
 <CAJ7c6TNVbeNsxbbj1QJTcjdkHRmJUBfF=iv_dOMDAGxoKY9CyQ@mail.gmail.com>
 <a3531c01-f6a9-4c85-be86-8df932b78400@app.fastmail.com>
 <ZrzCpy36C9w/X87C@fetter.org>
Subject: Re: [PATCH] Add get_bytes() and set_bytes() functions
Content-Type: text/plain
Content-Transfer-Encoding: 7bit
Archived-At: <https://www.postgresql.org/message-id/7b4236b7-079d-4f10-b2aa-efc83955f6df%40app.fastmail.com>
Precedence: bulk

On Wed, Aug 14, 2024, at 16:43, David Fetter wrote:
>> I also think it would be nice to provide these convenience functions:
>> to_bytes(bigint) -> bytea
>> from_bytes(bytea) -> bigint
>
> Along with these, would it make sense to have other forms of these
> that won't choke at 63 bits, e.g. NUMERIC or TEXT?

I wonder what would be good names for such functions though?

Since NUMERIC can have decimal digits, and since BYTEA can already be casted to
TEXT, which will just be \x followed by the hex digits, maybe such names should
include "integer" or some other word, to indicate what is being returned?

It's already quite easy to convert to NUMERIC though,
for users who are aware of tricks like this:
SELECT ('0x'||encode('\xCAFEBABEDEADBEEF'::bytea,'hex'))::numeric;
       numeric
----------------------
 14627333968688430831
(1 row)

But, I think it would be better to provide functions,
since many users probably have to google+stackoverflow or gpt
to learn such tricks, which are not in the official documentation.

Regards,
Joel