Re: PG17 optimizations to vacuum

On 03/09/2024 00:01, Peter Geoghegan wrote:
> On Mon, Sep 2, 2024 at 4:58 PM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>> Do you have any non-default settings? "select name,
>> current_setting(name), source  from pg_settings where setting <>
>> boot_val;" would show that.
> 
> What about page checksums?
> 
> One simple explanation is that we're writing extra FPIs to set hint
> bits. But that explanation only works if you assume that page-level
> checksums are in use (or that wal_log_hints is turned on).

Hmm, yeah, that might be it. With chceksums enabled, I see ~120k WAL 
records, vs ~90k without checksums. But there's no difference between 
v16 and master.

Pavel, did you test v17 with checksums enabled and v16 with checksums 
disabled, by any chance?

-- 
Heikki Linnakangas
Neon (https://neon.tech)