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Subject: Re: PostgreSQL 15-->18 slowdown?
From: Israel Brewster <ijbrewster@alaska.edu>
In-Reply-To: <1207571.1782499465@sss.pgh.pa.us>
Date: Fri, 26 Jun 2026 10:58:09 -0800
Cc: Ruben Morais <ruben.gmorais@gmail.com>,
 PostgreSQL General <pgsql-general@lists.postgresql.org>
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 <1207571.1782499465@sss.pgh.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
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> On Jun 26, 2026, at 10:44=E2=80=AFAM, Tom Lane <tgl@sss.pgh.pa.us> =
wrote:
>=20
> Israel Brewster <ijbrewster@alaska.edu> writes:
>=20
>>         SubPlan 1
>>           ->  Limit  (cost=3D0.00..0.48 rows=3D1 width=3D1)
>>                 ->  Nested Loop  (cost=3D0.00..13833793.79 =
rows=3D29105774 width=3D1)
>>                       ->  Seq Scan on tilt_data  =
(cost=3D0.00..13469970.40 rows=3D29105774 width=3D16)
>>                             Filter: (station =3D stations.id)
>>                       ->  Materialize  (cost=3D0.00..1.22 rows=3D1 =
width=3D16)
>>                             ->  Seq Scan on tilt_orientation  =
(cost=3D0.00..1.21 rows=3D1 width=3D16)
>>                                   Filter: (station =3D stations.id)
>=20
> Can you show us the EXPLAIN output for this part of the plan in v15?

I wish I could - I was wanting to see that myself. Unfortunately, I =
upgraded to 18 using =E2=80=94link, so by the time I discovered this =
issue, I had no way to go back to 15 (other than restoring from backups =
or the like), at least to the best of my knowledge.=20

---
Israel Brewster
Software Engineer
Alaska Volcano Observatory=20
Geophysical Institute - UAF=20
2156 Koyukuk Drive=20
Fairbanks AK 99775-7320
Work: 907-474-5172
cell:  907-328-9145=20

>=20
> 			regards, tom lane