From: Tom Lane <tgl@sss.pgh.pa.us>
To: Corey Huinker <corey.huinker@gmail.com>
cc: Jeff Davis <pgsql@j-davis.com>, Andres Freund <andres@anarazel.de>,
        Michael Paquier <michael@paquier.xyz>,
        jian he <jian.universality@gmail.com>,
        Nathan Bossart <nathandbossart@gmail.com>,
        Bruce Momjian <bruce@momjian.us>,
        Matthias van de Meent <boekewurm+postgres@gmail.com>,
        Magnus Hagander <magnus@hagander.net>,
        Stephen Frost <sfrost@snowman.net>,
        Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>,
        Peter Smith <smithpb2250@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
        alvherre@alvh.no-ip.org
Subject: Re: Statistics Import and Export
In-reply-to: <CADkLM=cCJFH7DE1W+nT4uAxgEL-gOBoKMQORJTnzmoXTFw231w@mail.gmail.com>
References: <sdno5atrplq5b67vcx7x6fkzevwkzojd23izbguy2yma424wmp@siwbi3ijxdxs> <x5yo5ly5u3dhzfaq3hrzeqhju3io5zmwk4yqrkge3ywcflffck@ghbbgsfv56yb> <3670503.1740173078@sss.pgh.pa.us> <blezfpeafycxlizyynwvwzh2vywmklhvfqudhicjrccu4raqpx@4ttfufowc2vo> <3728741.1740178078@sss.pgh.pa.us> <CADkLM=f0a43aTd88xW4xCFayEF25g-7hTrHX_WhV40HyocsUGg@mail.gmail.com> <97b451228227c555be1a4f79c4a62ddec9a74f06.camel@j-davis.com> <CADkLM=ckXu5wzSQZ3Y_fvAaL8rZ+upZdSecBLf5FCTMj7M6T-A@mail.gmail.com> <b227c4fca29dfb893bb414ce6d84fc2377489ecc.camel@j-davis.com> <CADkLM=dRMC6t8gp9GVf6y6E_r5EChQjMAAh_vPyih_zMiq0zvA@mail.gmail.com> <y2d36zf6pl3n6ni6e4ctblu3a5iazi2dycknq53h2mjvp7lto4@hhww3h2qgdrw> <6af48508a32499a8be3398cafffd29fb6188c44b.camel@j-davis.com> <CADkLM=cG8=gde_KjGiQC_wt0K3knJCy_mwvd-sW=f=3M2eSrEg@mail.gmail.com> <1698502.1740541206@sss.pgh.pa.us> <CADkLM=fZWAPyDxmHqxiJMUvrjbi2Fo1pHr+63_1d8yhStZ=sXQ@mail.gmail.com> <1704472.1740544569@sss.pgh.pa.us> <CADkLM=cCJFH7DE1W+nT4uAxgEL-gOBoKMQORJTnzmoX!
 TFw231w@mail.gmail.com>
Comments: In-reply-to Corey Huinker <corey.huinker@gmail.com>
	message dated "Tue, 25 Feb 2025 23:57:40 -0500"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <1707556.1740546344.1@sss.pgh.pa.us>
Date: Wed, 26 Feb 2025 00:05:44 -0500
Message-ID: <1707557.1740546344@sss.pgh.pa.us>
Archived-At: <https://www.postgresql.org/message-id/1707557.1740546344%40sss.pgh.pa.us>
Precedence: bulk

Corey Huinker <corey.huinker@gmail.com> writes:
> Just to confirm, we ARE able to assume dense packing of attributes in an
> index, and thus we can infer the attnum from the position of the attname in
> the aggregated array, and there's no need to do a parallel array_agg of
> attnums, yes?

Yes, absolutely, there are no dropped columns in indexes.  See
upthread discussion.

We could have avoided two sub-selects for attstattarget too,
on the same principle: just collect them all and sort it out
later.  That'd risk bloating pg_dump's storage, although maybe
we could have handled that by doing additional processing
while inspecting the results of getIndexes' query, so as not
to store anything in the common case.

			regards, tom lane