On 2020-May-12, Peter Geoghegan wrote:
> > The point is that when checking the table for corruption I avoid
> > calling anything that might assert (or segfault, or whatever).
>
> I don't think that you can expect to avoid assertion failures in
> general.
Hmm. I think we should (try to?) write code that avoids all crashes
with production builds, but not extend that to assertion failures.
Sticking again with the provided example,
> I'll stick with your example. You're calling
> TransactionIdDidCommit() from check_tuphdr_xids(), which will
> interrogate the commit log and pg_subtrans. It's just not under your
> control.
in a production build this would just fail with an error that the
pg_xact file cannot be found, which is fine -- if this happens in a
production system, you're not disturbing any other sessions. Or maybe
the file is there and the byte can be read, in which case you would get
the correct response; but that's fine too.
I don't know to what extent this is possible.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services