private String samplePartitionValues(List<String> partVals) {
    if (CollectionUtils.isEmpty(partVals)) {
      return ": Partitions = []";
    }
    StringBuilder sb = new StringBuilder(": Number of Partitions = " + partVals.size());
    sb.append(": Partitions = [");
    if (partVals.size() > LOG_SAMPLE_PARTITIONS_MAX_SIZE) {
      // extracting starting 2 values, and ending 2 values
      sb.append(join(partVals.subList(0, LOG_SAMPLE_PARTITIONS_HALF_SIZE), LOG_SAMPLE_PARTITIONS_SEPARATOR));
      sb.append(" .... ");
      sb.append(join(partVals.subList(partVals.size() - LOG_SAMPLE_PARTITIONS_HALF_SIZE, partVals.size()),
              LOG_SAMPLE_PARTITIONS_SEPARATOR));
    } else {
      sb.append(join(partVals, LOG_SAMPLE_PARTITIONS_SEPARATOR));
    }
    sb.append("]");
    return sb.toString();
  }
add admin users if they don't exist.

This is a potential contention when HiveServer2 using embedded metastore and Metastore
Server try to concurrently invoke addAdminUsers. If one failed, JDOException was caught for
one more time try, if failed again, simply ignored by warning, which meant another succeeds.

@throws MetaException
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/HMSHandler.java