/* Update the oldest ID. */
if (WT_TXNID_LT(prev_oldest_id, oldest_id) || last_running_moved) {
        /*
         * We know we want to update.  Check if we're racing.
         */
         ...
} else {
        if (WT_VERBOSE_ISSET(session, WT_VERB_TRANSACTION) &&
            current_id - oldest_id > 10000 && last_running_moved &&
            oldest_session != NULL) {
                (void)__wt_verbose(session, WT_VERB_TRANSACTION,
                    "old snapshot %" PRIu64
                    " pinned in session %d [%s]"
                    " with snap_min %" PRIu64 "\n",
                    oldest_id, oldest_session->id,
                    oldest_session->lastop,
                    oldest_session->txn.snap_min);
        }
        WT_ASSERT(session, txn_global->scan_count > 0);
        (void)__wt_atomic_subiv32(&txn_global->scan_count, 1);
}