Horton

Re: Fix overflow of nbatch

David Rowley <dgrowleyml@gmail.com>

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From: David Rowley <dgrowleyml@gmail.com>
To: Tomas Vondra <tomas@vondra.me>
Cc: Vaibhav Jain <jainva@google.com>, pgsql-hackers@postgresql.org, Madhukar <madhukarprasad@google.com>, Sangeetha Seshadri <sangsesh@google.com>
Date: 2025-09-23T00:02:42Z
Lists: pgsql-hackers 
On Tue, 23 Sept 2025 at 09:31, Tomas Vondra <tomas@vondra.me> wrote:
> On 9/22/25 22:45, David Rowley wrote:
> > I think a1b4f289b mistakenly thought that there'd be size_t arithmetic
> > in the following two lines because the final result is a size_t:
> >
> > size_t current_space = hash_table_bytes + (2 * nbatch * BLCKSZ);
> > size_t new_space = hash_table_bytes * 2 + (nbatch * BLCKSZ);
> >
>
> Yeah, I failed to notice this part of the formula can overflow.

Ok cool. We're just in the freeze for 18.0 at the moment. Once that's
over, should I take care of this, or do you want to?

David

Commits

  1. Fix hashjoin memory balancing logic