MIME-Version: 1.0
From: Chris Cleveland <ccleveland@dieselpoint.com>
Date: Mon, 29 Apr 2024 11:17:15 -0500
Message-ID: <CABSN6VcacvmoVog6x3ueEk1X4iw_4SzHPiKe82JvsrEdwpH2Mg@mail.gmail.com>
Subject: Possible to get LIMIT in an index access method?
To: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Content-Type: multipart/alternative; boundary="000000000000e3c42806173e96d8"
Archived-At: <https://www.postgresql.org/message-id/CABSN6VcacvmoVog6x3ueEk1X4iw_4SzHPiKe82JvsrEdwpH2Mg%40mail.gmail.com>
Precedence: bulk

--000000000000e3c42806173e96d8
Content-Type: text/plain; charset="UTF-8"

I'm developing an index access method.

SELECT *
FROM foo
WHERE col <=> constant
ORDER BY col <==> constant
LIMIT 10;

I'm successfully getting the WHERE and the ORDER BY clauses in my
beginscan() method. Is there any way to get the LIMIT (or OFFSET, for that
matter)?

My access method is designed such that you have to fetch the entire result
set in one go. It's not streaming, like most access methods. As such, it
would be very helpful to know up front how many items I need to fetch from
the index.

-- 
Chris Cleveland
312-339-2677 mobile

--000000000000e3c42806173e96d8
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr"><div>I&#39;m developing an index access method.</div><div>=
<br></div><div>SELECT *</div><div>FROM foo</div><div>WHERE col &lt;=3D&gt; =
constant</div><div>ORDER BY col &lt;=3D=3D&gt; constant</div><div>LIMIT 10;=
</div><div><br></div><div>I&#39;m successfully getting the WHERE and the OR=
DER BY clauses in my beginscan() method. Is there any way to get the LIMIT =
(or OFFSET, for that matter)?</div><div><br></div><div>My access method is =
designed such that you have to fetch the entire result set in one go. It=
9;s not streaming, like most access methods. As such, it would be very help=
ful to know up front how many items I need to fetch from the index.<br></di=
v><br><div><span class=3D"gmail_signature_prefix">-- </span><br><div dir=3D=
"ltr" class=3D"gmail_signature" data-smartmail=3D"gmail_signature"><div dir=
=3D"ltr"><div><div dir=3D"ltr"><span><div><div dir=3D"ltr">Chris Cleveland<=
div>312-339-2677 mobile</div></div></div></span></div></div></div></div></d=
iv></div>

--000000000000e3c42806173e96d8--