private void logDelete(String qual, long ts, String delType) {
    if (VERBOSE) {
      LOG.info("del " + delType + ": row " + Bytes.toStringBinary(put.getRow()) + ", cf " + FAMILY
        + ", qualifier " + qual + ", ts " + ts);
    }
  }
Disable this when this test fails hopelessly and you need to debug a simpler case.
hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestSeekOptimizations.java