Class BigQueryReadClient (2.8.0)

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>)

BigQuery Read API. The Read API can be used to read data from BigQuery. New code should use the v1 Read API going forward, if they don't use Write API at the same time.

Properties

transport

Returns the transport used by the client instance.

Returns

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.

Parameters

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 `transport` instance is provided. (1) The `api_endpoint` property can be used to override the default endpoint provided by the client. GOOGLE_API_USE_MTLS_ENDPOINT environment variable can also be used to override the endpoint: "always" (always use the default mTLS endpoint), "never" (always use the default regular endpoint) and "auto" (auto switch to the default mTLS endpoint if client certificate is present, this is the default value). However, the `api_endpoint` property takes precedence if provided. (2) If GOOGLE_API_USE_CLIENT_CERTIFICATE environment variable is "true", then the `client_cert_source` property can be used to provide client certificate for mutual TLS transport. If not provided, the default SSL client certificate will be used if present. If GOOGLE_API_USE_CLIENT_CERTIFICATE is "false" or not set, no client certificate will be used.
`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 `None`, then default info will be used. Generally, you only need to set this if you're developing your own client library.

Exceptions

Type	Description
`google.auth.exceptions.MutualTLSChannelError`	If mutual TLS transport creation failed for any reason.

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[google.cloud.bigquery_storage_v1beta2.types.storage.CreateReadSessionRequest] = None, *, parent: Optional[str] = None, read_session: Optional[google.cloud.bigquery_storage_v1beta2.types.stream.ReadSession] = None, max_stream_count: Optional[int] = None, retry: google.api_core.retry.Retry = <_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.

Parameters

Name	Description
`request`	`google.cloud.bigquery_storage_v1beta2.types.CreateReadSessionRequest` The request object. Request message for `CreateReadSession`.
`parent`	`str` Required. The request project that owns the session, in the form of `projects/{project_id}`. This corresponds to the `parent` field on the `request` instance; if `request` is provided, this should not be set.
`read_session`	`google.cloud.bigquery_storage_v1beta2.types.ReadSession` Required. Session to be created. This corresponds to the `read_session` field on the `request` instance; if `request` is provided, this should not be set.
`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 `max_stream_count` field on the `request` instance; if `request` is provided, this should not be set.
`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.

Returns

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.

Parameter

Name	Description
`filename`	`str` The path to the service account private key json file.

Returns

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.

Parameter

Name	Description
`info`	`dict` The service account private key info.

Returns

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.

Parameter

Name	Description
`filename`	`str` The path to the service account private key json file.

Returns

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(request: Optional[google.cloud.bigquery_storage_v1beta2.types.storage.ReadRowsRequest] = None, *, read_stream: Optional[str] = None, offset: Optional[int] = None, retry: google.api_core.retry.Retry = <_MethodDefault._DEFAULT_VALUE: <object object>>, timeout: Optional[float] = None, metadata: Sequence[Tuple[str, str]] = ())

Reads rows from the stream in the format prescribed by the ReadSession. Each response contains one or more table rows, up to a maximum of 100 MiB per response; read requests which attempt to read individual rows larger than 100 MiB will fail.

Each request also returns a set of stream statistics reflecting the current state of the stream.

Parameters

Name	Description
`request`	`google.cloud.bigquery_storage_v1beta2.types.ReadRowsRequest` The request object. Request message for `ReadRows`.
`read_stream`	`str` Required. Stream to read rows from. This corresponds to the `read_stream` field on the `request` instance; if `request` is provided, this should not be set.
`offset`	`int` The offset requested must be less than the last row read from Read. Requesting a larger offset is undefined. If not specified, start reading from offset zero. This corresponds to the `offset` field on the `request` instance; if `request` is provided, this should not be set.
`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.

Returns

Type	Description
`Iterable[google.cloud.bigquery_storage_v1beta2.types.ReadRowsResponse]`	Response from calling ReadRows may include row data, progress and throttling information.

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[google.cloud.bigquery_storage_v1beta2.types.storage.SplitReadStreamRequest] = None, *, retry: google.api_core.retry.Retry = <_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.

Parameters

Name	Description
`request`	`google.cloud.bigquery_storage_v1beta2.types.SplitReadStreamRequest` The request object. Request message for `SplitReadStream`.
`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.