From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: Ron Johnson <ronljohnsonjr@gmail.com>,
        "pgsql-generallists.postgresql.org" <pgsql-general@lists.postgresql.org>
Subject: Re: Postgres do not support tinyint?
In-reply-to: <CAKFQuwYYgPxUSvo2UzOty5Cd1xw5+2q1bg3+zY-nsXNZyq+_4g@mail.gmail.com>
References: <CA+FnnTzfvgVdptHcLBFPrq_Q+xPes-Bhjiw_xFiooq4VqhqyrQ@mail.gmail.com> <CANzqJaCxZK0j8fL-riZpX+AV+kyo9PcAvgF=H5DgaWK+C+66Vw@mail.gmail.com> <CAKFQuwYYgPxUSvo2UzOty5Cd1xw5+2q1bg3+zY-nsXNZyq+_4g@mail.gmail.com>
Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
	message dated "Tue, 07 Jan 2025 23:44:21 -0700"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <1590895.1736319214.1@sss.pgh.pa.us>
Date: Wed, 08 Jan 2025 01:53:34 -0500
Message-ID: <1590896.1736319214@sss.pgh.pa.us>
Archived-At: <https://www.postgresql.org/message-id/1590896.1736319214%40sss.pgh.pa.us>
Precedence: bulk

"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Tuesday, January 7, 2025, Ron Johnson <ronljohnsonjr@gmail.com> wrote:
>> 3. The "bit" type might serve your needs.

> You suggest a type with a minimum size of 6 bytes when the complaint is
> that the otherwise acceptable 2 byte data type is too large?

I think the point here is that there's zero value in trying to pack a
small integer value into 1 byte (let alone 4 bits) if it's all by
its lonesome in the row.  Alignment padding will eat whatever gain
you thought you had.  If you want a win, you need to store a lot of
such values in one field.  Ron's suggesting that you pack them into
bit arrays and manually insert/extract individual values.  That could
be worth doing if you were sufficiently desperate, but you'd have to
value compact storage over access simplicity quite a lot.

Perhaps a "char"[] array (note the quotes) would provide an
intermediate level of compactness versus pain.

			regards, tom lane