public List<RegionInfo> getMergeRegions(RegionInfo region) throws IOException {
    return CatalogFamilyFormat.getMergeRegions(getRegionCatalogResult(region).rawCells());
  }
Returns Return all regioninfos listed in the 'info:merge*' columns of the given {@code region}.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/RegionStateStore.java