Re: Can the backend return more than one error message per PQexec?

Tom Lane writes:

> Since there will always be asynchronous conditions to deal with, it'd
> be pretty foolish to design a protocol that assumes that exactly one
> 'E' message will arrive during a PQexec cycle.

Reasonable.

> > I am currently looking into extending the protocol so that more fields can
> > be in an ErrorResponse (e.g., error codes).  If this were to happen then
> > we'd need a smarter way of handling more than one error message per cycle.
>
> Only if you want to overload ErrorResponse so that successive 'E'
> messages mean different things.  I do not think that would be a good
> design.  It'd be better to allow ErrorResponse to carry multiple fields.

That's the idea.  But I can hardly concatenate the error codes, can I?  I
looks as though we need an API where all the messages (errors + notices)
from each query cycle are collected and can be cycled through after
completion.

> This'd imply a protocol version bump, but so what?  Changing the
> semantics of ErrorResponse probably ought to require that anyway.

I think I could have done with a minor bump, but if you have some plans,
too, the easier.

-- 
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter