presto-kudu/src/main/java/io/prestosql/plugin/kudu/KuduMetadata.java/KuduMetadata/listTableColumns
class KuduMetadata:    @Override
    public Map<SchemaTableName, List<ColumnMetadata>> listTableColumns(ConnectorSession session, SchemaTablePrefix prefix)
    {
        requireNonNull(prefix, "SchemaTablePrefix is null");

        List<SchemaTableName> tables;
        if (!prefix.getTable().isPresent()) {
            tables = listTables(session, prefix.getSchema());
        }
        else {
            tables = ImmutableList.of(prefix.toSchemaTableName());
        }

        ImmutableMap.Builder<SchemaTableName, List<ColumnMetadata>> columns = ImmutableMap.builder();
        for (SchemaTableName tableName : tables) {
            KuduTableHandle tableHandle = getTableHandle(session, tableName);
            if (tableHandle != null) {
                ConnectorTableMetadata tableMetadata = getTableMetadata(tableHandle);
                columns.put(tableName, tableMetadata.getColumns());
            }
        }
        return columns.build();
    }