private KeyIterator executeKeySliceQuery(@Nullable byte[] startKey,
                                        @Nullable byte[] endKey,
                                        FilterList filters,
                                        @Nullable SliceQuery columnSlice) throws BackendException {
    Scan scan = new Scan().addFamily(columnFamilyBytes);

    try {
        scan.setTimeRange(0, Long.MAX_VALUE);
    } catch (IOException e) {
        throw new PermanentBackendException(e);
    }

    if (startKey != null)
        scan.setStartRow(startKey);

    if (endKey != null)
        scan.setStopRow(endKey);

    if (columnSlice != null) {
        filters.addFilter(getFilter(columnSlice));
    }

    TableMask table = null;

    try {
        table = cnx.getTable(tableName);
        return new RowIterator(table, table.getScanner(scan.setFilter(filters)), columnFamilyBytes);
    } catch (IOException e) {
        IOUtils.closeQuietly(table);
        throw new PermanentBackendException(e);
    }
}