BigQueryReadClient(*, credentials: Optional[google.auth.credentials.Credentials] = None, transport: Optional[Union[str, google.cloud.bigquery_storage_v1beta2.services.big_query_read.transports.base.BigQueryReadTransport]] = None, client_options: Optional[google.api_core.client_options.ClientOptions] = None, client_info: google.api_core.gapic_v1.client_info.ClientInfo = <google.api_core.gapic_v1.client_info.ClientInfo object>)Client for interacting with BigQuery Storage API.
The BigQuery storage API can be used to read data stored in BigQuery.
Properties
transport
Returns the transport used by the client instance.
| Type | Description |
BigQueryReadTransport | The transport used by the client instance. |
Methods
BigQueryReadClient
BigQueryReadClient(*, credentials: Optional[google.auth.credentials.Credentials] = None, transport: Optional[Union[str, google.cloud.bigquery_storage_v1beta2.services.big_query_read.transports.base.BigQueryReadTransport]] = None, client_options: Optional[google.api_core.client_options.ClientOptions] = None, client_info: google.api_core.gapic_v1.client_info.ClientInfo = <google.api_core.gapic_v1.client_info.ClientInfo object>)Instantiates the big query read client.
| Name | Description |
credentials |
Optional[google.auth.credentials.Credentials]
The authorization credentials to attach to requests. These credentials identify the application to the service; if none are specified, the client will attempt to ascertain the credentials from the environment. |
transport |
Union[str, BigQueryReadTransport]
The transport to use. If set to None, a transport is chosen automatically. |
client_options |
google.api_core.client_options.ClientOptions
Custom options for the client. It won't take effect if a |
client_info |
google.api_core.gapic_v1.client_info.ClientInfo
The client info used to send a user-agent string along with API requests. If |
| Type | Description |
google.auth.exceptions.MutualTLSChannelError | If mutual TLS transport creation failed for any reason. |
__exit__
__exit__(type, value, traceback)Releases underlying transport's resources.
common_billing_account_path
common_billing_account_path(billing_account: str)Returns a fully-qualified billing_account string.
common_folder_path
common_folder_path(folder: str)Returns a fully-qualified folder string.
common_location_path
common_location_path(project: str, location: str)Returns a fully-qualified location string.
common_organization_path
common_organization_path(organization: str)Returns a fully-qualified organization string.
common_project_path
common_project_path(project: str)Returns a fully-qualified project string.
create_read_session
create_read_session(request: Optional[Union[google.cloud.bigquery_storage_v1beta2.types.storage.CreateReadSessionRequest, dict]] = None, *, parent: Optional[str] = None, read_session: Optional[google.cloud.bigquery_storage_v1beta2.types.stream.ReadSession] = None, max_stream_count: Optional[int] = None, retry: Union[google.api_core.retry.Retry, google.api_core.gapic_v1.method._MethodDefault] = <_MethodDefault._DEFAULT_VALUE: <object object>>, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = ())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 6 hours after they are created and do not require manual clean-up by the caller.
| Name | Description |
request |
Union[google.cloud.bigquery_storage_v1beta2.types.CreateReadSessionRequest, dict]
The request object. Request message for |
parent |
str
Required. The request project that owns the session, in the form of |
read_session |
google.cloud.bigquery_storage_v1beta2.types.ReadSession
Required. Session to be created. This corresponds to the |
max_stream_count |
int
Max initial number of streams. If unset or zero, the server will provide a value of streams so as to produce reasonable throughput. Must be non- negative. The number of streams may be lower than the requested number, depending on the amount parallelism that is reasonable for the table. Error will be returned if the max count is greater than the current system max limit of 1,000. Streams must be read starting from offset 0. This corresponds to the |
retry |
google.api_core.retry.Retry
Designation of what errors, if any, should be retried. |
timeout |
float
The timeout for this request. |
metadata |
Sequence[Tuple[str, str]]
Strings which should be sent along with the request as metadata. |
| Type | Description |
google.cloud.bigquery_storage_v1beta2.types.ReadSession | Information about the ReadSession. |
from_service_account_file
from_service_account_file(filename: str, *args, **kwargs)Creates an instance of this client using the provided credentials file.
| Name | Description |
filename |
str
The path to the service account private key json file. |
| Type | Description |
BigQueryReadClient | The constructed client. |
from_service_account_info
from_service_account_info(info: dict, *args, **kwargs)Creates an instance of this client using the provided credentials info.
| Name | Description |
info |
dict
The service account private key info. |
| Type | Description |
BigQueryReadClient | The constructed client. |
from_service_account_json
from_service_account_json(filename: str, *args, **kwargs)Creates an instance of this client using the provided credentials file.
| Name | Description |
filename |
str
The path to the service account private key json file. |
| Type | Description |
BigQueryReadClient | The constructed client. |
parse_common_billing_account_path
parse_common_billing_account_path(path: str)Parse a billing_account path into its component segments.
parse_common_folder_path
parse_common_folder_path(path: str)Parse a folder path into its component segments.
parse_common_location_path
parse_common_location_path(path: str)Parse a location path into its component segments.
parse_common_organization_path
parse_common_organization_path(path: str)Parse a organization path into its component segments.
parse_common_project_path
parse_common_project_path(path: str)Parse a project path into its component segments.
parse_read_session_path
parse_read_session_path(path: str)Parses a read_session path into its component segments.
parse_read_stream_path
parse_read_stream_path(path: str)Parses a read_stream path into its component segments.
parse_table_path
parse_table_path(path: str)Parses a table path into its component segments.
read_rows
read_rows(name, offset=0, retry=<_MethodDefault._DEFAULT_VALUE: <object object>>, timeout=<_MethodDefault._DEFAULT_VALUE: <object object>>, metadata=(), retry_delay_callback=None)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
| Name | Description |
name |
str
Required. Name of the stream to start reading from, of the form |
offset |
Optional[int]
The starting offset from which to begin reading rows from in the stream. The offset requested must be less than the last row read from ReadRows. Requesting a larger offset is undefined. |
retry |
Optional[google.api_core.retry.Retry]
A retry object used to retry requests. If |
timeout |
Optional[float]
The amount of time, in seconds, to wait for the request to complete. Note that if |
metadata |
Optional[Sequence[Tuple[str, str]]]
Additional metadata that is provided to the method. |
retry_delay_callback |
Optional[Callable[[float], None]]
If the client receives a retryable error that asks the client to delay its next attempt and retry_delay_callback is not None, BigQueryReadClient will call retry_delay_callback with the delay duration (in seconds) before it starts sleeping until the next attempt. |
| Type | Description |
google.api_core.exceptions.GoogleAPICallError | If the request failed for any reason. |
google.api_core.exceptions.RetryError | If the request failed due to a retryable error and retry attempts failed. |
ValueError | If the parameters are invalid. |
| Type | Description |
ReadRowsStream | An iterable of ReadRowsResponse. |
read_session_path
read_session_path(project: str, location: str, session: str)Returns a fully-qualified read_session string.
read_stream_path
read_stream_path(project: str, location: str, session: str, stream: str)Returns a fully-qualified read_stream string.
split_read_stream
split_read_stream(request: Optional[Union[google.cloud.bigquery_storage_v1beta2.types.storage.SplitReadStreamRequest, dict]] = None, *, retry: Union[google.api_core.retry.Retry, google.api_core.gapic_v1.method._MethodDefault] = <_MethodDefault._DEFAULT_VALUE: <object object>>, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = ())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.
| Name | Description |
request |
Union[google.cloud.bigquery_storage_v1beta2.types.SplitReadStreamRequest, dict]
The request object. Request message for |
retry |
google.api_core.retry.Retry
Designation of what errors, if any, should be retried. |
timeout |
float
The timeout for this request. |
metadata |
Sequence[Tuple[str, str]]
Strings which should be sent along with the request as metadata. |
table_path
table_path(project: str, dataset: str, table: str)Returns a fully-qualified table string.