Re: PostgreSQL 18 GA press release draft

Jonathan S. Katz <jkatz@postgresql.org>

From: "Jonathan S. Katz" <jkatz@postgresql.org>
To: John Naylor <johncnaylorls@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2025-09-12T01:55:07Z
Lists: pgsql-hackers
On 9/10/25 9:52 AM, John Naylor wrote:
> On Wed, Sep 10, 2025 at 10:13 AM Jonathan S. Katz <jkatz@postgresql.org> wrote:
> 
>> PostgreSQL 18 also supports using x86 AVX-512 instructions for CRC32 calculations, which are used in page checksums and are also available in the new [`crc32`](https://www.postgresql.org/docs/18/functions-binarystring.html#FUNCTIONS-BINARYSTRING-OTHER) function.
> 
> Hi Jon,
> 
> The checksum stored in the page header is not actually a CRC but
> something else entirely. WAL records are a convenient example of
> something that uses CRC.
> 
> Also, CRC32 is not hardware accelerated, only CRC32C is. We have two
> SQL-callable functions.  To avoid confusion maybe they can be omitted
> from this longer-than-usual announcement -- they seem like a niche
> feature anyway.

Thanks; I've removed the reference.

Jonathan