4 ms·
>Within the keyspace, identifiers are well-ordered [6]. That means each ID has a successor and a predecessor. Minor nitpick, but really it only guarantees a su
by contravariant 10y ago
>Within the keyspace, identifiers are well-ordered [6]. That means each ID has a successor and a predecessor.
Minor nitpick, but really it only guarantees a successor. In particular the natural numbers are well ordered, but 0 (or 1, depending on what convention you're using) doesn't have a predecessor.
Edit: worse the keyspace depicted doesn't appear to be well ordered since it doesn't seem to have a lower limit. It's possible the author meant "totally ordered" although strictly speaking that also doesn't guarantee a predecessor or successor.
- rdtsc 10y ago> Minor nitpick, but really it only guarantees a successor. That's from the consistent hashing chapter. That uses a ring usually [0,2^p-1]. With p=160 if SHA is the hash algorithm. Then the predecessor of 0 is then 2^p-1.
- contravariant 10y agoIn that case it's still neither well ordered, or even 'ordered' in any mathematical sense. I was merely pointing out that 'well ordered' doesn't convey whatever it was the author was trying to say.
- dozzie 10y ago>> Within the keyspace, identifiers are well-ordered [6]. That means each ID has a successor and a predecessor. > Minor nitpick, but really it only guarantees a successor. Not really. Finite sets can be well-ordered, too.