---
sidebar:
  label: roboto.formats.parquet
  order: 2
title: roboto.formats.parquet
---
Fetching and decoding topic data stored in Parquet files.

Covers cache-policy-driven opening of remote Parquet files (local cache reuse, atomic download, or HTTP streaming), row-group time filtering, column projection from schema field paths, and timestamp extraction.

## Submodules

- [roboto.formats.parquet.arrow_to_roboto](/docs/reference/python-sdk/roboto/formats/parquet/arrow_to_roboto)
- [roboto.formats.parquet.fetch](/docs/reference/python-sdk/roboto/formats/parquet/fetch)
- [roboto.formats.parquet.parquet_parser](/docs/reference/python-sdk/roboto/formats/parquet/parquet_parser)
- [roboto.formats.parquet.table_transforms](/docs/reference/python-sdk/roboto/formats/parquet/table_transforms)
- [roboto.formats.parquet.timestamp](/docs/reference/python-sdk/roboto/formats/parquet/timestamp)

## Package Contents

- [ParquetParser](/reference/python-sdk/roboto/formats/parquet/parquet_parser#roboto.formats.parquet.parquet_parser.ParquetParser) (class)

- [Timestamp](/reference/python-sdk/roboto/formats/parquet/timestamp#roboto.formats.parquet.timestamp.Timestamp) (class): The timestamp field of a Parquet file, the field holding each row's timestamp.

- [compute_time_filter_mask()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.compute_time_filter_mask) (function): Compute a boolean mask indicating which rows fall within the specified time range.

- [extract_timestamp_field()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.extract_timestamp_field) (function): Find a Parquet file's timestamp field and describe it as a [`Timestamp`](/reference/python-sdk/roboto/formats/parquet/timestamp#roboto.formats.parquet.timestamp.Timestamp).

- [extract_timestamps()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.extract_timestamps) (function): Extract timestamps in nanoseconds since Unix epoch from the table's timestamp field.

- [generate_message_path_requests()](/reference/python-sdk/roboto/formats/parquet/arrow_to_roboto#roboto.formats.parquet.arrow_to_roboto.generate_message_path_requests) (function): Generate AddMessagePathRequest objects for all fields in a Parquet schema.

- [narrow_list_nested_fields()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.narrow_list_nested_fields) (function): Prune list-of-struct columns to the projected leaves inside each element.

- [open_parquet_file()](/reference/python-sdk/roboto/formats/parquet/fetch#roboto.formats.parquet.fetch.open_parquet_file) (function): Open a remote Parquet file under a cache policy, from the cheapest available source.

- [parquet_file_from_url()](/reference/python-sdk/roboto/formats/parquet/fetch#roboto.formats.parquet.fetch.parquet_file_from_url) (function): Open a Parquet file over HTTP via a signed URL (no local download).

- [resolve_columns()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.resolve_columns) (function): Build a deduplicated list of column names safe for `read_row_group(columns=...)`.

- [select_fields()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.select_fields) (function): Keep only the fields `fields` names, found by walking their path components, in the table's order.

- [should_narrow_list_nested_fields()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.should_narrow_list_nested_fields) (function): Return whether [`narrow_list_nested_fields()`](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.narrow_list_nested_fields) would change the table.

- [should_read_row_group()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.should_read_row_group) (function): Determine whether a Parquet row group contains data within the requested time range.

- [timestamp_statistics()](/reference/python-sdk/roboto/formats/parquet/table_transforms#roboto.formats.parquet.table_transforms.timestamp_statistics) (function): The statistics of the timestamp's column chunk in a row group, or `None` when there are none to use.