presto-iceberg/src/main/java/io/prestosql/plugin/iceberg/IcebergMetadata.java/IcebergMetadata/addColumn
class IcebergMetadata:    @Override
    public void addColumn(ConnectorSession session, ConnectorTableHandle tableHandle, ColumnMetadata column)
    {
        IcebergTableHandle handle = (IcebergTableHandle) tableHandle;
        org.apache.iceberg.Table icebergTable = getIcebergTable(metastore, hdfsEnvironment, session, handle.getSchemaTableName());
        icebergTable.updateSchema().addColumn(column.getName(), toIcebergType(column.getType())).commit();
    }