Re: parallel data loading for pgbench -i

Hi Lakshmi,

On 19/01/2026 09:25, lakshmi wrote:
>
> Hi Mircea,
>
> I tested the patch on 19devel and it worked well for me.
> Before applying it, |-j| is rejected in pgbench initialization mode as
> expected. After applying the patch, |pgbench -i -s 100 -j 10| runs
> successfully and shows a clear speedup.
> On my system the total runtime dropped to about 9.6s, with client-side
> data generation around 3.3s.
> I also checked correctness after the run — row counts for
> pgbench_accounts, pgbench_branches, and pgbench_tellers all match the
> expected values.
>
> Thanks for working on this, the improvement is very noticeable.
>
> Best regards,
> lakshmi
>
Thanks for having a look and trying it out!

FYI this is one of Tomas Vondra's patch ideas from his blog [1].

I have attached a new version which now includes docs, tests, a proposed
commit message, and an attempt to fix the current CI failures (Windows).

[1] - https://vondra.me/posts/patch-idea-parallel-pgbench-i

--
Thanks,
Mircea Cadariu