The PostgreSQL COPY protocol requires an explicit initialization phase
that may fail, and in this case the Postmodern driver transaction is
already dead, so there's no way we can even send ABORT to it.
Review the error handling of our copy-batch function to cope with that
fact, and add some logging of non-retryable errors we may have.
Also improve the thread error reporting when using a binary image from
where it might be difficult to open an interactive debugger, while still
having the full blown Common Lisp debugging experience for the project
developers.
Add a test case for a missing column as in issue #339.
Fix#339, see #337.