Viktor Dukhovni:
> > On Jul 26, 2016, at 5:12 PM, Peter <pe...@pajamian.dhs.org> wrote:
> >
> > Would doing another cache read right before the update be an easy fix
> > for this? I do realize this would add additional latency to postscreen,
> > hopefully not too much.
>
> This still leaves a race condition in place, though it would be for a shorter
> time.
Yes, I would not want to double the number of database accesses.
It was easy enough to share one in-memory copy of postscreen cache
data among multiple SMTP sessions, by introducing one more level
of indirection.
Now it is a matter of carefully reading and updating that shared
state, and avoiding unnecessary postscreen cache lookups and updates
when SMTP sessions from the same client overlap in time.
Wietse
