I looked through the patch. Sources are OK. However I didn't find any docs and test cases. Would you please provide me with short description on this feature and why it is important. Because I didn't manage to find the old Andrew Dunstan's post either.
I wrote a prototype of this patch, and it works well
postgres=# set client_encoding to 'latin2'; SET Time: 1.488 ms postgres=# \copy (select xmlelement(name xx, d) from d) to ~/d.xml (format 'raw') COPY 1 Time: 1.108 ms postgres=# copy (select xmlelement(name xx, d) from d) to stdout (format 'raw') ; <?xml version="1.0" encoding="LATIN2"?><xx>příliš žluťoučký kůň</xx>Time: 1.000 ms
