presto-main/src/main/java/io/prestosql/metadata/MetadataManager.java/MetadataManager/getColumnMetadata
class MetadataManager:    @Override
    public ColumnMetadata getColumnMetadata(Session session, TableHandle tableHandle, ColumnHandle columnHandle)
    {
        requireNonNull(tableHandle, "tableHandle is null");
        requireNonNull(columnHandle, "columnHandle is null");

        CatalogName catalogName = tableHandle.getCatalogName();
        ConnectorMetadata metadata = getMetadata(session, catalogName);
        return metadata.getColumnMetadata(session.toConnectorSession(catalogName), tableHandle.getConnectorHandle(), columnHandle);
    }