spamd does not update /var/db/spamd

Hi,

I'm trying to use spamd to block spam using graylisting, but the spamd
database is not updated.

I run /usr/libexec/spamd -v -d to see what's happening and I definitely
see hosts connecting to it:

(GREY) 209.85.219.176: mytestemail@gmail.com> -> <hello@ezaquarii.com>
Got Grey HELO mail-yb1-f176.google.com, IP 209.85.219.176 from
<mytestemail@gmail.com> to <hello@ezaquarii.com>
added 209.85.219.176
mail-yb1-f176.google.com
<mytestemail@gmail.com>
<hello@ezaquarii.com>
209.85.219.176 connected for 11 seconds.

I also tried to submit an email using Python SMTP library and I
confirmed 451 Temporary failure response.

But when I browse /var/db/spamd, there is nothing there.

My spamd is running and is referring to a correct file:

# ps aux | grep spamd
_spamd 93211 0.0 0.1 9672 1492 ?? Isp 5:29AM 0:00.00 spamd:
(pf <spamd-white> update) (spamd)
_spamd 59023 0.0 0.5 10012 4836 ?? Ip 5:29AM 0:00.02 spamd:
[priv] (greylist) (spamd)
_spamd 13468 0.0 0.1 9640 1172 ?? Ip 5:29AM 0:00.00 spamd:
(/var/db/spamd update) (spamd)

Database file has correct perms:

# ls- l /var/db/spamd
-rw-r--r-- 1 _spamd _spamd 65536 Oct 30 05:30 /var/db/spamd

# spamdb /var/db/spamd
<empty output>

My spamd config is default.
OpenBSD 6.3.

What is wrong with it?

Best regards,
Chris