From: Antonin Houska <ah@cybertec.at>
To: alvherre@kurilemu.de
cc: Chao Li <li.evan.chao@gmail.com>, Andres Freund <andres@anarazel.de>,
    Pg Hackers <pgsql-hackers@lists.postgresql.org>,
    Zsolt Parragi <zsolt.parragi@percona.com>,
    Nathan Bossart <nathandbossart@gmail.com>
Subject: Re: table AM option passing
In-reply-to: <202604011827.p4mx4bh2ti46@alvherre.pgsql>
References: <202604011827.p4mx4bh2ti46@alvherre.pgsql>
Comments: In-reply-to =?us-ascii?Q?=3D=3Futf-8=3FQ=3F=3DC3=3D81lvaro=3F=3D?=
 Herrera <alvherre@kurilemu.de>
   message dated "Wed, 01 Apr 2026 20:41:01 +0200."
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Date: Thu, 02 Apr 2026 07:39:43 +0200
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=C3=81lvaro Herrera <alvherre@kurilemu.de> wrote:

> On 2026-Apr-01, Antonin Houska wrote:

> I realized that patch 0003 is doing two different things, and they
> should each be their own patch which can be rejected if we don't like
> them; so I split it in two.  One moves the heapam.h-private bit to the
> 32th bit.

I'm sorry I haven't recalled yesterday, but this technique resembles the
DSM keys in parallel.c:


  /*
   * Magic numbers for per-context parallel state sharing.  Higher-level co=
de
   * should use smaller values, leaving these very large ones for use by th=
is
   * module.
   */
  #define PARALLEL_KEY_FIXED		UINT64CONST(0xFFFFFFFFFFFF0001)
  ...


What I found inspiring here is that the "core" uses the high bits while use=
rs
of the API use the lower ones. Perhaps it'd be appropriate in v6-0001 to
reserve the high bits for the TABLE_ options and leave the lower ones for t=
he
HEAP_ options. If someone implements a new AM (possibly as an extension), it
should be more comfortable for him.

--=20
Antonin Houska
Web: https://www.cybertec-postgresql.com