@Override
  public boolean isMergeable() {
    if (!isAvailable()) {
      LOG.debug("Region " + this + " is not mergeable because it is closing or closed");
      return false;
    }
    if (hasReferences()) {
      LOG.debug("Region " + this + " is not mergeable because it has references");
      return false;
    }

    return true;
  }
Returns store services for this region, to access services required by store level needs
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java