public static Counter getOpenConnectionsCounter() {
    return getOrCreateCounter(MetricsConstants.OPEN_CONNECTIONS);
  }
Get a Map that represents a multi-field metric,
or create a new one if it does not already exist.
@param name Name of map metric.  This should come from MetricConstants
@return MapMetric .
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/metastore/metrics/Metrics.java