On Fri, Aug 11, 2023 at 11:18:09AM +0530, Amit Kapila wrote: > On Fri, Aug 11, 2023 at 10:43 AM Julien Rouhaud <rjuju...@gmail.com> wrote: > > I disagree. As I mentioned before any module registered in > > shared_preload_libraries can spawn background workers which can perform any > > activity. There were previous reports of corruption because of multi-xact > > being generated by such bgworkers during pg_upgrade, I'm pretty sure that > > there > > are some modules that create objects (automatic partitioning tools for > > instance). It's also unclear to me what would happen if some writes are > > performed by such module at various points of the pg_upgrade process. > > Couldn't > > that lead to either data loss or broken slot (as it couldn't stream changes > > from older major version)? > > It won't be any bad than what can happen to tables. If we know that > such bgworkers can cause corruption if they do writes during the > upgrade, I don't think it is the job of this patch to prevent the > related scenarios. We can probably disallow the creation of new slots > during the binary upgrade but that also I am not sure. I guess it > would be better to document such hazards as a first step and then > probably write a patch to prevent WAL writes or something along those > lines.
Yes, if users are connecting to the clusters during pg_upgrade, we have many more problems than slots. -- Bruce Momjian <br...@momjian.us> https://momjian.us EDB https://enterprisedb.com Only you can decide what is important to you.
