Re: Potential G2-item cycles under serializable isolation

On 6/3/20 10:20 AM, Kyle Kingsbury wrote:
> On 6/2/20 7:17 PM, Peter Geoghegan wrote: >> It seems kind of inconvenient to run Jepsen -- I suppose I could >> use
Docker or something like that, but I don't have experience >> with it. What do
you think is the simplest workflow for somebody >> that just wants to recreate
your result on a Debian system? > > I'll see about writing a version of the test
that doesn't use any of > the automation, so you can point it at a local
postgres instance. > Then all you'll need is lein and a jdk.
OK, I think we're all set. With Jepsen 0ec25ec3, you should be able to run:

cd stolon;

lein run test-all -w append --max-writes-per-key 4 --concurrency 50 -r 500
--isolation serializable --time-limit 60 --nemesis none --existing-postgres
--node localhost --no-ssh --postgres-user jepsen --postgres-password pw

... and it'll connect to an already-running instance of Postgres on localhost
(or whatever you want to connect to) using the provided username and password.
It expects a DB with the same name as the user. You'll need a JDK (1.8 or
higher), and Leiningen (https://leiningen.org/) which should be pretty easy to
install. :)

> Could you test Postgres 9.5? It would be nice to determine if this > is a new issue, or a regression.

I can also confirm that Postgres 9.5.22, 10.13, and 11.8 all exhibit the same
G2-item anomalies as 12.3. It looks like this issue has been here a while!
(Either that, or... my transactions are malformed?).

Is there additional debugging data I can get you that'd be helpful? Or if you'd
like, I can hop in an IRC or whatever kind of chat/video session you'd like to
help you get these Jepsen tests running.

--Kyle