Re: PSQL error: total cell count of XXX exceeded

From: Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Michael Paquier <michael(at)paquier(dot)xyz>, Hongxu Ma <interma(at)outlook(dot)com>, Jelte Fennema <postgres(at)jeltef(dot)nl>, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: PSQL error: total cell count of XXX exceeded
Date: 2023-11-20 20:48:35
Message-ID: 202311202048.n2a3dsjldhne@alvherre.pgsql
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

On 2023-Sep-12, Tom Lane wrote:

> I'm more than a bit skeptical about trying to do something about this,
> simply because this range of query result sizes is far past what is
> practical. The OP clearly hasn't tested his patch on actually
> overflowing query results, and I don't care to either.

I think we're bound to hit this limit at some point in the future, and
it seems easy enough to solve. I propose the attached, which is pretty
much what Hongxu last submitted, with some minor changes.

Having this make a difference requires some 128GB of RAM, so it's not a
piece of cake, but it's an amount that can be reasonably expected to be
physically installed in real machines nowadays.

(I first thought we could just use pg_mul_s32_overflow during
printTableInit and raise an error if that returns true, but that just
postpones the problem.)

Álvaro Herrera 48°01'N 7°57'E —
Subversion to GIT: the shortest path to happiness I've ever heard of
(Alexey Klyukin)

Attachment Content-Type Size
v5-0001-Avoid-overflow-in-fe_utils-printTable-API.patch text/x-diff 3.7 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Robert Haas 2023-11-20 20:51:33 Re: Partial aggregates pushdown
Previous Message Andres Freund 2023-11-20 20:41:10 Re: Add recovery to pg_control and remove backup_label