Client for interacting with BigQuery Storage API.

The BigQuery storage API can be used to read data stored in BigQuery.

Instantiate the big query read client.

Creates a new read session. A read session divides the contents of a BigQuery table into one or more streams, which can then be used to read data from the table. The read session also specifies properties of the data to be read, such as a list of columns or a push- down filter describing the rows to be returned.

A particular row can be read by at most one stream. When the caller has reached the end of each stream in the session, then all the data in the table has been read.

Data is assigned to each stream such that roughly the same number of rows can be read from each stream. Because the server-side unit for assigning data is collections of rows, the API does not guarantee that each stream will return the same number or rows. Additionally, the limits are enforced based on the number of pre-filtered rows, so some filters can lead to lopsided assignments.

Read sessions automatically expire 24 hours after they are created and do not require manual clean-up by the caller.

Creates an instance of this client using the provided credentials file.

Creates an instance of this client using the provided credentials file.

Parse a read_session path into its component segments.

Parse a read_stream path into its component segments.

Reads rows from the table in the format prescribed by the read session. Each response contains one or more table rows, up to a maximum of 10 MiB per response; read requests which attempt to read individual rows larger than this will fail.

Each request also returns a set of stream statistics reflecting the estimated total number of rows in the read stream. This number is computed based on the total table size and the number of active streams in the read session, and may change as other streams continue to read data.

.. rubric:: Example

from google.cloud import bigquery_storage

client = bigquery_storage.BigQueryReadClient()

TODO: Initialize table:

table = "projects/{}/datasets/{}/tables/{}".format( ... 'project_id': 'your-data-project-id', ... 'dataset_id': 'your_dataset_id', ... 'table_id': 'your_table_id', ... )

TODO: Initialize parent:

parent = 'projects/your-billing-project-id'

requested_session = bigquery_storage.types.ReadSession( ... table=table, ... data_format=bigquery_storage.types.DataFormat.AVRO, ... ) session = client.create_read_session( ... parent=parent, read_session=requested_session ... )

stream = session.streams[0], # TODO: Also read any other streams. read_rows_stream = client.read_rows(stream.name)

for element in read_rows_stream.rows(session): ... # process element ... pass

Return a fully-qualified read_session string.

Return a fully-qualified read_stream string.

Splits a given ReadStream into two ReadStream objects. These ReadStream objects are referred to as the primary and the residual streams of the split. The original ReadStream can still be read from in the same manner as before. Both of the returned ReadStream objects can also be read from, and the rows returned by both child streams will be the same as the rows read from the original stream.

Moreover, the two child streams will be allocated back-to-back in the original ReadStream. Concretely, it is guaranteed that for streams original, primary, and residual, that original[0-j] = primary[0-j] and original[j-n] = residual[0-m] once the streams have been read to completion.