Re: isolation tester limitation in case of multiple injection points in a single command

On Sun, Oct 19, 2025 at 03:41:00PM +0200, Mihail Nikalayeu wrote:
> Hello, everyone!
>
> While stabilizing tests for [0] I realized I have no idea how to set
> up a pretty simple scenario using an isolation tester.
>
> It looks like this:
> * session S1 start long running query (CREATE INDEX CONCURRENTLY) and
> traps into injection point X
> * session S2 executes some command
> * session S2 wakes up S1
> * now S2 needs to run one more command BUT only AFTER S1 traps into
> another injection point Y (and it is still the same CREATE INDEX)
> <------- tricky part here

Ah, OK. So you want to have one single command, still wait through
two injection points inside it. I am wondering about one thing: do
you really require that? Could it be simpler to have two
permutations, each one of them using one wait point to check your two
scenarios?

> So, my proposal options:
> a) tell me if there's a clear solution I missed
> b) for 'wait' injection_point - learn isolation tester to detect it
> and implement logic like 'S2_query(S1 traps Y)'
> c) learn isolation tester to treat 'notice' from injection_point the
> same way as RAISE NOTICE + (preferable) add possibility to
> apply 'notice' and 'wait' for the same injection point (like
> 'wait+notice')
> d) add injection_point_await - utility to wait until injected point is not
> "waited" by some backend
>
> What do you think? Any other ideas?

Something close to what you are suggested in b), that can be defined
in the specs, sounds like a natural solution to me. It also feels
like a better approach from the spec's reader perspective, as well:
this would document multiple wait steps in the test itself.
--
Michael