Noah Misch <noah@leadboat.com> writes:
> ... agreed. In general, recycling SLRU space entails three steps that shall
> not overlap:
> 1. Stop reading data in the space, regulated by some "logical tail".
> 2. Unlink files wholly within the bounds of the space.
> 3. Start writing data into the space, regulated by some "physical tail" (most
> often called a "stop limit").
Check.
> Commit d4031d7 fixed overlap of (2) and (3). For pg_notify, though, it
> introduced overlap of (1) and (2). I've now checked the other SLRUs for
> similar problems, but I found nothing urgent:
Good, I was wondering if we had any similar issues elsewhere.
> I think we don't yet have the right name here, seeing QUEUE_TAIL_PAGE !=
> QUEUE_POS_PAGE(QUEUE_TAIL) sounds paradoxical, yet happens regularly. How
> about naming it QUEUE_STOP_PAGE?
Hmm, it's not very clear what "stop" means here. What do you think of
QUEUE_OLDEST_PAGE?
regards, tom lane