Hi. I just tried adding the xmin pseudo-column to my COPY, and I get an error. Using a regular SELECT works fine.
Is that normal? that's a `COPY tab(xmin, cols...) ...` Do I need to switch to a `COPY (select xmin, cols... from tab) ...` to access xmin? And if I do that, any performance implications for the COPY? The reason I'm using COPY is performance and its "streaming" behavior. (modulo the "big row" non-streaming issue from my as-yet unanswered post from today). I'm thus interested in how a `COPY tab(cols...)` differs from a `COPY (select cols from tab ...)` in terms of implementation and performance. Thanks, --DD
