A semantic that came up in discussions about Riak: we could return the current value if we're failing a WT_CURSOR::insert call with key-exist.

One risk: we'd be discarding the application-set value of the WT_CURSOR::insert call, replacing it with something else.

This means loops like:

ret = WT_CURSOR::insert()
if (ret == WT_DUPLICATE_KEY) {
        ret = WT_CURSOR::get()
        /* muck about with the value */
        ret = WT_CURSOR::update()
}

would require one less engine call.

Michael, I didn't want this one to get lost, kill it if you don't like it.