Re: [PATCH] Improve REPACK (CONCURRENTLY) error messages for unsupported configurations

On 2026-May-27, Chao Li wrote:

> > On May 27, 2026, at 11:06, Baji Shaik <baji(dot)pgdev(at)gmail(dot)com> wrote:

> >
> > 0001 -- When wal_level < replica, REPACK (CONCURRENTLY) currently
> > surfaces generic "replication slots ... wal_level" error
> > from CheckSlotRequirements(), with a CONTEXT line referring
> > to an internal worker. Add an upfront check that reports a
> > REPACK-specific error.
>
> LGTM

Pushed this one earlier. I changed the errcode though, because in my
mind "object" is a database object, and the server configuration is not
an object. So I used INVALID_PARAMETER_VALUE instead. I also don't
think it makes sense to say "cannot repack table X", so the user leaves
thinking they could repack table Y instead. The whole point being that
you cannot vacuum _any_ tables. So I made the errmsg() say that.

> When I was working on 832e220d99a, I actually considered for more
> detailed error messages, but I ended up giving up. I think we should
> be careful about adding more branches here unless the existing message
> is causing significant confusion in practice.
>
> So, I personally don’t like 0002.

I'll give this a look after some icecream.

> > 0003 -- Four ereport(ERROR) calls in the REPACK CONCURRENTLY code
> > path lack errcode() and default to ERRCODE_INTERNAL_ERROR.
> > Add appropriate errcodes; in particular, the
> > apply_concurrent_update/delete failures map cleanly to
> > ERRCODE_T_R_SERIALIZATION_FAILURE.

Also pushed, with additional editorialization. I have recollections of
out message policy saying something about "could not do X" instead of
"failed to do X", so I changed it that way. (But I couldn't find that
in the style guide.)

--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/