private static void deleteQuotas(final Connection connection, final byte[] rowKey,
    final byte[] qualifier) throws IOException {
    Delete delete = new Delete(rowKey);
    if (qualifier != null) {
      delete.addColumns(QUOTA_FAMILY_INFO, qualifier);
    }
    if (isNamespaceRowKey(rowKey)) {
      String ns = getNamespaceFromRowKey(rowKey);
      Quotas namespaceQuota = getNamespaceQuota(connection, ns);
      if (namespaceQuota != null && namespaceQuota.hasSpace()) {
        // When deleting namespace space quota, also delete table usage(u:p) snapshots
        deleteTableUsageSnapshotsForNamespace(connection, ns);
      }
    }
    doDelete(connection, delete);
  }
Returns true if the support for quota is enabled
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaUtil.java