Re: Issues with blocksize smaller than 8KB

On Sat, Oct 18, 2025 at 10:02 AM Casey Shobe <casey(dot)allen(dot)shobe(at)icloud(dot)com>
wrote:

> I have been comparing performance of postgresql (18.0) compiled for
> various block sizes etc., and found that while 8kb and 16kb builds work
> fine, a 4kb build does not, with identical configuration. When I try to
> initialize pgbench, --scale=10 works fine, but the --scale=100 I was trying
> and even just --scale=20 result in a long delay on the vacuum analyze step
> followed by Postgres crashing due to a segmentation fault.
>
> I also found that initdb fails when I compile for a blocksize of either
> 1KB or 2KB build:
>
> 2025-10-17 15:39:13.182 UTC [97433] DETAIL: The database cluster was
> initialized with RELSEG_SIZE 1895825408, but the server was compiled with
> RELSEG_SIZE 1895825408.
> 2025-10-17 15:39:13.182 UTC [97433] HINT: It looks like you need to
> recompile or initdb.
>

Like Tom, I can't reproduce any of these problems. If the problem exists
after cleaning the build tree and repeating, then please let us know your
hardware, OS and version, and the command lines you used to configure and
to build.

Cheers,

Jeff