On Wednesday, May 19, 2021 1:52 PM Amit Kapila <amit.kapila16@gmail.com> wrote:
> > > I am not sure but I
> > > > think we should prohibit truncate on user_catalog_tables as we
> > > > prohibit truncate on system catalog tables (see below [1]) if we
> > > > want plugin to lock them, otherwise, as you said it might lead to
> deadlock.
> > > > For the matter, I think we should once check all other operations
> > > > where we can take an exclusive lock on [user]_catalog_table, say
> > > > Cluster command, and compare the behavior of same on system
> > > > catalog tables.
> > > >
> > > > [1]
> > > > postgres=# truncate pg_class;
> > > > ERROR: permission denied: "pg_class" is a system catalog
> > > > postgres=# cluster pg_class;
> > > > ERROR: there is no previously clustered index for table "pg_class"
> > > >
> > >
> > > Please ignore the cluster command as we need to use 'using index'
> > > with that command to make it successful. I just want to show the
> > > truncate command behavior for which you have asked the question.
> > Thank you so much for clarifying the direction.
> > I agree with the changing the TRUNCATE side.
> > I'll make a patch based on this.
> >
>
> Isn't it a better idea to start a new thread where you can summarize whatever
> we have discussed here about user_catalog_tables? We might get the opinion
> from others about the behavior change you are proposing.
You are right. So, I've launched it with the patch for this.
Best Regards,
Takamichi Osumi