public static Set<String> getNamespaceSnapshots(Connection conn) throws IOException {
    try (Table quotaTable = conn.getTable(QUOTA_TABLE_NAME);
      ResultScanner rs = quotaTable.getScanner(createScanForNamespaceSnapshotSizes())) {
      Set<String> snapshots = new HashSet<>();
      for (Result r : rs) {
        CellScanner cs = r.cellScanner();
        while (cs.advance()) {
          cs.current();
          snapshots.add(getNamespaceFromRowKey(r.getRow()));
        }
      }
      return snapshots;
    }
  }
Returns a set of the names of all namespaces containing snapshot entries.
@param conn connection to re-use
hbase-client/src/main/java/org/apache/hadoop/hbase/quotas/QuotaTableUtil.java