private static void println(PrintWriter pw, String msg) {
    if (pw != null) {
      pw.println(msg);
    }
  }
count some heuristics - num files in {@link AcidUtils#ORIGINAL_PATTERN_COPY} format.  These
are supported but if there are a lot of them there will be a perf hit on read until
major compaction
ql/src/java/org/apache/hadoop/hive/ql/util/UpgradeTool.java