Re: Testing LISTEN/NOTIFY more effectively - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Testing LISTEN/NOTIFY more effectively
Date
Msg-id 25695.1564276130@sss.pgh.pa.us
Whole thread Raw
In response to Re: Testing LISTEN/NOTIFY more effectively  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Andres Freund <andres@anarazel.de> writes:
> I wonder if there aren't similar dangers around the notify handling. In
> your patch we don't print them particularly eagerly. Doesn't that also
> open us up to timing concerns?

I think probably not, because of the backend-side restrictions on when
notify messages will be sent.  The corresponding case for the NOTICE
bug we just fixed would be if a backend sent a NOTIFY before blocking;
but it can't do that internally to a transaction, and anyway the proposed
test script isn't doing anything that tricky.

I did spend some time thinking about how isolationtester might report
notifys that are sent spontaneously (without any "triggering" query)
but I didn't feel that that was worth messing with.  We'd have to
have the program checking all the connections not just the one that's
running what it thinks is the currently active step.

We might be approaching a time where it's worth scrapping the
isolationtester logic and starting over.  I'm not volunteering though.

            regards, tom lane



pgsql-hackers by date:

Previous
From: Andres Freund
Date:
Subject: Re: Testing LISTEN/NOTIFY more effectively
Next
From: Tom Lane
Date:
Subject: Re: pg_upgrade fails with non-standard ACL