Re: Potential G2-item cycles under serializable isolation

On Thu, Jun 4, 2020 at 5:20 PM Peter Geoghegan <pg@bowt.ie> wrote:
> On Thu, Jun 4, 2020 at 3:11 PM Kyle Kingsbury <aphyr@jepsen.io> wrote:
> > Yes! It's not always this obvious--G2-item encompasses any dependency cycle
> > between transactions such that at least one dependency involves a transaction
> > writing state which was not observed by some (ostensibly prior) transaction's
> > read. We call these "rw dependencies" in the paper, because they involve a read
> > which must have occurred before a write. Another way to think of G2-item is "A
> > transaction failed to see something that happened in its logical past".
>
> Are you familiar with the paper "Serializable Snapshot Isolation in
> PostgreSQL"? You might find it helpful:
>
> http://vldb.org/pvldb/vol5/p1850_danrkports_vldb2012.pdf
>
> Is there a difference between "rw dependencies" as you understand the
> term, and what the paper calls "rw-antidependencies"?

"3.2 Serializability Theory" has some stuff about Adya et al, but also
talks about the work of Fekete et al -- apparently they built on the
Adya paper (both papers share one author). Are you familiar with the
Fekete paper?


-- 
Peter Geoghegan