presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/RaptorMetadata.java/RaptorMetadata/getColumnHandles
class RaptorMetadata:    @Override
    public Map<String, ColumnHandle> getColumnHandles(ConnectorSession session, ConnectorTableHandle tableHandle)
    {
        RaptorTableHandle raptorTableHandle = (RaptorTableHandle) tableHandle;
        ImmutableMap.Builder<String, ColumnHandle> builder = ImmutableMap.builder();
        for (TableColumn tableColumn : dao.listTableColumns(raptorTableHandle.getTableId())) {
            builder.put(tableColumn.getColumnName(), getRaptorColumnHandle(tableColumn));
        }

        RaptorColumnHandle uuidColumn = shardUuidColumnHandle();
        builder.put(uuidColumn.getColumnName(), uuidColumn);

        if (raptorTableHandle.isBucketed()) {
            RaptorColumnHandle bucketNumberColumn = bucketNumberColumnHandle();
            builder.put(bucketNumberColumn.getColumnName(), bucketNumberColumn);
        }

        return builder.build();
    }