@Override
    void perform() throws IOException {
      HTableDescriptor selected = selectTable(disabledTables);
      if (selected == null) {
        return;
      }
      HColumnDescriptor columnDesc = selectFamily(selected);
      if (columnDesc == null) {
        return;
      }

      Admin admin = connection.getAdmin();
      int versions = RandomUtils.nextInt(10) + 3;
      try {
        TableName tableName = selected.getTableName();
        LOG.info(
            "Altering versions of column family: "
                + columnDesc
                + " to: "
                + versions
                + " in table: "
                + tableName);
        columnDesc.setMinVersions(versions);
        columnDesc.setMaxVersions(versions);
        admin.modifyTable(tableName, selected);
        // assertion
        HTableDescriptor freshTableDesc = admin.getTableDescriptor(tableName);
        HColumnDescriptor freshColumnDesc = freshTableDesc.getFamily(columnDesc.getName());
        Assert.assertEquals(
            "Column family: " + columnDesc + " was not altered",
            freshColumnDesc.getMaxVersions(),
            versions);
        Assert.assertEquals(
            "Column family: " + freshColumnDesc + " was not altered",
            freshColumnDesc.getMinVersions(),
            versions);
        LOG.info(
            "Altered versions of column family: "
                + columnDesc
                + " to: "
                + versions
                + " in table: "
                + tableName);
        disabledTables.put(tableName, freshTableDesc);
      } catch (Exception e) {
        LOG.warn("Caught exception in action: " + this.getClass());
        throw e;
      } finally {
        admin.close();
      }
      verifyTables();
    }
    @Override
    void perform() throws IOException {
      HTableDescriptor selected = selectTable(disabledTables);
      if (selected == null) {
        return;
      }
      HColumnDescriptor columnDesc = selectFamily(selected);
      if (columnDesc == null) {
        return;
      }

      Admin admin = connection.getAdmin();
      try {
        TableName tableName = selected.getTableName();
        // possible DataBlockEncoding ids
        int[] possibleIds = {0, 2, 3, 4, 6};
        short id = (short) possibleIds[RandomUtils.nextInt(possibleIds.length)];
        LOG.info(
            "Altering encoding of column family: "
                + columnDesc
                + " to: "
                + id
                + " in table: "
                + tableName);
        columnDesc.setDataBlockEncoding(DataBlockEncoding.getEncodingById(id));
        admin.modifyTable(tableName, selected);
        // assertion
        HTableDescriptor freshTableDesc = admin.getTableDescriptor(tableName);
        HColumnDescriptor freshColumnDesc = freshTableDesc.getFamily(columnDesc.getName());
        Assert.assertEquals(
            "Encoding of column family: " + columnDesc + " was not altered",
            freshColumnDesc.getDataBlockEncoding().getId(),
            id);
        LOG.info(
            "Altered encoding of column family: "
                + freshColumnDesc
                + " to: "
                + id
                + " in table: "
                + tableName);
        disabledTables.put(tableName, freshTableDesc);
      } catch (Exception e) {
        LOG.warn("Caught exception in action: " + this.getClass());
        throw e;
      } finally {
        admin.close();
      }
      verifyTables();
    }