Class BigQueryStorageClient (3.5.2)

Service Description: BigQuery storage API.

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

This class provides the ability to make remote calls to the backing service through method calls that map to API methods. Sample code to get started:

 
 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   TableReference tableReference = TableReference.newBuilder().build();
   String parent = "";
   int requestedStreams = 0;
   ReadSession response = bigQueryStorageClient.createReadSession(tableReference, parent, requestedStreams);
 }

Note: close() needs to be called on the bigQueryStorageClient object to clean up resources such as threads. In the example above, try-with-resources is used, which automatically calls close().

The surface of this class includes several types of Java methods for each of the API's methods:

A "flattened" method. With this type of method, the fields of the request type have been converted into function parameters. It may be the case that not all fields are available as parameters, and not every API method will have a flattened method entry point.
A "request object" method. This type of method only takes one parameter, a request object, which must be constructed before the call. Not every API method will have a request object method.
A "callable" method. This type of method takes no parameters and returns an immutable API callable object, which can be used to initiate calls to the service.

See the individual methods for example code.

Many parameters require resource names to be formatted in a particular way. To assist with these names, this class includes a format method for each type of name, and additionally a parse method to extract the individual identifiers contained within names that are returned.

This class can be customized by passing in a custom instance of BigQueryStorageSettings to create(). For example:

To customize credentials:

 
 BigQueryStorageSettings bigQueryStorageSettings =
     BigQueryStorageSettings.newBuilder()
         .setCredentialsProvider(FixedCredentialsProvider.create(myCredentials))
         .build();
 BigQueryStorageClient bigQueryStorageClient =
     BigQueryStorageClient.create(bigQueryStorageSettings);

To customize the endpoint:

 
 BigQueryStorageSettings bigQueryStorageSettings =
     BigQueryStorageSettings.newBuilder().setEndpoint(myEndpoint).build();
 BigQueryStorageClient bigQueryStorageClient =
     BigQueryStorageClient.create(bigQueryStorageSettings);

Inheritance

java.lang.Object > BigQueryStorageClient

Static Methods

create()

public static final BigQueryStorageClient create()

Constructs an instance of BigQueryStorageClient with default settings.

Returns
Type	Description
`BigQueryStorageClient`

Exceptions
Type	Description
`IOException`

create(BigQueryStorageSettings settings)

public static final BigQueryStorageClient create(BigQueryStorageSettings settings)

Constructs an instance of BigQueryStorageClient, using the given settings. The channels are created based on the settings passed in, or defaults for any settings that are not set.

Parameter
Name	Description
`settings`	`BigQueryStorageSettings`

Returns
Type	Description
`BigQueryStorageClient`

Exceptions
Type	Description
`IOException`

create(EnhancedBigQueryStorageStub stub)

public static final BigQueryStorageClient create(EnhancedBigQueryStorageStub stub)

Constructs an instance of BigQueryStorageClient, using the given stub for making calls. This is for advanced usage - prefer to use BigQueryStorageSettings}.

Parameter
Name	Description
`stub`	`EnhancedBigQueryStorageStub`

Returns
Type	Description
`BigQueryStorageClient`

Constructors

BigQueryStorageClient(BigQueryStorageSettings settings)

protected BigQueryStorageClient(BigQueryStorageSettings settings)

Constructs an instance of BigQueryStorageClient, using the given settings. This is protected so that it is easy to make a subclass, but otherwise, the static factory methods should be preferred.

Parameter
Name	Description
`settings`	`BigQueryStorageSettings`

BigQueryStorageClient(EnhancedBigQueryStorageStub stub)

protected BigQueryStorageClient(EnhancedBigQueryStorageStub stub)

Parameter
Name	Description
`stub`	`EnhancedBigQueryStorageStub`

Methods

awaitTermination(long duration, TimeUnit unit)

public boolean awaitTermination(long duration, TimeUnit unit)

Parameters
Name	Description
`duration`	`long`
`unit`	`TimeUnit`

Returns
Type	Description
`boolean`

Exceptions
Type	Description
`InterruptedException`

batchCreateReadSessionStreams(Storage.BatchCreateReadSessionStreamsRequest request)

public final Storage.BatchCreateReadSessionStreamsResponse batchCreateReadSessionStreams(Storage.BatchCreateReadSessionStreamsRequest request)

Creates additional streams for a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task upwards by adding additional workers.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   ReadSession session = ReadSession.newBuilder().build();
   int requestedStreams = 0;
   BatchCreateReadSessionStreamsRequest request = BatchCreateReadSessionStreamsRequest.newBuilder()
     .setSession(session)
     .setRequestedStreams(requestedStreams)
     .build();
   BatchCreateReadSessionStreamsResponse response = bigQueryStorageClient.batchCreateReadSessionStreams(request);
 }

Parameter
Name	Description
`request`	`Storage.BatchCreateReadSessionStreamsRequest` The request object containing all of the parameters for the API call.

Returns
Type	Description
`Storage.BatchCreateReadSessionStreamsResponse`

batchCreateReadSessionStreams(Storage.ReadSession session, int requestedStreams)

public final Storage.BatchCreateReadSessionStreamsResponse batchCreateReadSessionStreams(Storage.ReadSession session, int requestedStreams)

Creates additional streams for a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task upwards by adding additional workers.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   ReadSession session = ReadSession.newBuilder().build();
   int requestedStreams = 0;
   BatchCreateReadSessionStreamsResponse response = bigQueryStorageClient.batchCreateReadSessionStreams(session, requestedStreams);
 }

Parameters
Name	Description
`session`	`Storage.ReadSession` Required. Must be a non-expired session obtained from a call to CreateReadSession. Only the name field needs to be set.
`requestedStreams`	`int` Required. Number of new streams requested. Must be positive. Number of added streams may be less than this, see CreateReadSessionRequest for more information.

Returns
Type	Description
`Storage.BatchCreateReadSessionStreamsResponse`

batchCreateReadSessionStreamsCallable()

public final UnaryCallable<Storage.BatchCreateReadSessionStreamsRequest,Storage.BatchCreateReadSessionStreamsResponse> batchCreateReadSessionStreamsCallable()

Creates additional streams for a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task upwards by adding additional workers.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   ReadSession session = ReadSession.newBuilder().build();
   int requestedStreams = 0;
   BatchCreateReadSessionStreamsRequest request = BatchCreateReadSessionStreamsRequest.newBuilder()
     .setSession(session)
     .setRequestedStreams(requestedStreams)
     .build();
   ApiFuture<BatchCreateReadSessionStreamsResponse> future = bigQueryStorageClient.batchCreateReadSessionStreamsCallable().futureCall(request);
   // Do something
   BatchCreateReadSessionStreamsResponse response = future.get();
 }

Returns
Type	Description
`UnaryCallable<BatchCreateReadSessionStreamsRequest,BatchCreateReadSessionStreamsResponse>`

close()

public final void close()

createReadSession(Storage.CreateReadSessionRequest request)

public final Storage.ReadSession createReadSession(Storage.CreateReadSessionRequest request)

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.

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

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   TableReference tableReference = TableReference.newBuilder().build();
   String parent = "";
   CreateReadSessionRequest request = CreateReadSessionRequest.newBuilder()
     .setTableReference(tableReference)
     .setParent(parent)
     .build();
   ReadSession response = bigQueryStorageClient.createReadSession(request);
 }

Parameter
Name	Description
`request`	`Storage.CreateReadSessionRequest` The request object containing all of the parameters for the API call.

Returns
Type	Description
`Storage.ReadSession`

createReadSession(TableReferenceProto.TableReference tableReference, String parent, int requestedStreams)

public final Storage.ReadSession createReadSession(TableReferenceProto.TableReference tableReference, String parent, int requestedStreams)

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.

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

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   TableReference tableReference = TableReference.newBuilder().build();
   String parent = "";
   int requestedStreams = 0;
   ReadSession response = bigQueryStorageClient.createReadSession(tableReference, parent, requestedStreams);
 }

Parameters
Name	Description
`tableReference`	`TableReferenceProto.TableReference` Required. Reference to the table to read.
`parent`	`String` Required. String of the form "projects/your-project-id" indicating the project this ReadSession is associated with. This is the project that will be billed for usage.
`requestedStreams`	`int` Optional. Initial number of streams. If unset or 0, we 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 and the maximum amount of parallelism allowed by the system. Streams must be read starting from offset 0.

Returns
Type	Description
`Storage.ReadSession`

createReadSessionCallable()

public final UnaryCallable<Storage.CreateReadSessionRequest,Storage.ReadSession> createReadSessionCallable()

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.

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

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   TableReference tableReference = TableReference.newBuilder().build();
   String parent = "";
   CreateReadSessionRequest request = CreateReadSessionRequest.newBuilder()
     .setTableReference(tableReference)
     .setParent(parent)
     .build();
   ApiFuture<ReadSession> future = bigQueryStorageClient.createReadSessionCallable().futureCall(request);
   // Do something
   ReadSession response = future.get();
 }

Returns
Type	Description
`UnaryCallable<CreateReadSessionRequest,ReadSession>`

finalizeStream(Storage.FinalizeStreamRequest request)

public final void finalizeStream(Storage.FinalizeStreamRequest request)

Triggers the graceful termination of a single stream in a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task downwards without losing data.

This API does not delete the stream -- it remains visible in the ReadSession, and any data processed by the stream is not released to other streams. However, no additional data will be assigned to the stream once this call completes. Callers must continue reading data on the stream until the end of the stream is reached so that data which has already been assigned to the stream will be processed.

This method will return an error if there are no other live streams in the Session, or if SplitReadStream() has been called on the given Stream.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream stream = Stream.newBuilder().build();
   FinalizeStreamRequest request = FinalizeStreamRequest.newBuilder()
     .setStream(stream)
     .build();
   bigQueryStorageClient.finalizeStream(request);
 }

Parameter
Name	Description
`request`	`Storage.FinalizeStreamRequest` The request object containing all of the parameters for the API call.

finalizeStream(Storage.Stream stream)

public final void finalizeStream(Storage.Stream stream)

Triggers the graceful termination of a single stream in a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task downwards without losing data.

This method will return an error if there are no other live streams in the Session, or if SplitReadStream() has been called on the given Stream.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream stream = Stream.newBuilder().build();
   bigQueryStorageClient.finalizeStream(stream);
 }

Parameter
Name	Description
`stream`	`Storage.Stream` Stream to finalize.

finalizeStreamCallable()

public final UnaryCallable<Storage.FinalizeStreamRequest,Empty> finalizeStreamCallable()

Triggers the graceful termination of a single stream in a ReadSession. This API can be used to dynamically adjust the parallelism of a batch processing task downwards without losing data.

This method will return an error if there are no other live streams in the Session, or if SplitReadStream() has been called on the given Stream.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream stream = Stream.newBuilder().build();
   FinalizeStreamRequest request = FinalizeStreamRequest.newBuilder()
     .setStream(stream)
     .build();
   ApiFuture<Void> future = bigQueryStorageClient.finalizeStreamCallable().futureCall(request);
   // Do something
   future.get();
 }

Returns
Type	Description
`UnaryCallable<FinalizeStreamRequest,Empty>`

getSettings()

public final BigQueryStorageSettings getSettings()

Returns
Type	Description
`BigQueryStorageSettings`

getStub()

public EnhancedBigQueryStorageStub getStub()

Returns
Type	Description
`EnhancedBigQueryStorageStub`

isShutdown()

public boolean isShutdown()

Returns
Type	Description
`boolean`

isTerminated()

public boolean isTerminated()

Returns
Type	Description
`boolean`

readRowsCallable()

public final ServerStreamingCallable<Storage.ReadRowsRequest,Storage.ReadRowsResponse> readRowsCallable()

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.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   StreamPosition readPosition = StreamPosition.newBuilder().build();
   ReadRowsRequest request = ReadRowsRequest.newBuilder()
     .setReadPosition(readPosition)
     .build();

   ServerStream<ReadRowsResponse> stream = bigQueryStorageClient.readRowsCallable().call(request);
   for (ReadRowsResponse response : stream) {
     // Do something when receive a response
   }
 }

Returns
Type	Description
`ServerStreamingCallable<ReadRowsRequest,ReadRowsResponse>`

shutdown()

public void shutdown()

shutdownNow()

public void shutdownNow()

splitReadStream(Storage.SplitReadStreamRequest request)

public final Storage.SplitReadStreamResponse splitReadStream(Storage.SplitReadStreamRequest request)

Splits a given read stream into two Streams. These streams are referred to as the primary and the residual of the split. The original stream can still be read from in the same manner as before. Both of the returned streams can also be read from, and the total rows return 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 Stream. 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.

This method is guaranteed to be idempotent.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream originalStream = Stream.newBuilder().build();
   SplitReadStreamRequest request = SplitReadStreamRequest.newBuilder()
     .setOriginalStream(originalStream)
     .build();
   SplitReadStreamResponse response = bigQueryStorageClient.splitReadStream(request);
 }

Parameter
Name	Description
`request`	`Storage.SplitReadStreamRequest` The request object containing all of the parameters for the API call.

Returns
Type	Description
`Storage.SplitReadStreamResponse`

splitReadStream(Storage.Stream originalStream)

public final Storage.SplitReadStreamResponse splitReadStream(Storage.Stream originalStream)

This method is guaranteed to be idempotent.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream originalStream = Stream.newBuilder().build();
   SplitReadStreamResponse response = bigQueryStorageClient.splitReadStream(originalStream);
 }

Parameter
Name	Description
`originalStream`	`Storage.Stream` Stream to split.

Returns
Type	Description
`Storage.SplitReadStreamResponse`

splitReadStreamCallable()

public final UnaryCallable<Storage.SplitReadStreamRequest,Storage.SplitReadStreamResponse> splitReadStreamCallable()

This method is guaranteed to be idempotent.

Sample code:


 try (BigQueryStorageClient bigQueryStorageClient = BigQueryStorageClient.create()) {
   Stream originalStream = Stream.newBuilder().build();
   SplitReadStreamRequest request = SplitReadStreamRequest.newBuilder()
     .setOriginalStream(originalStream)
     .build();
   ApiFuture<SplitReadStreamResponse> future = bigQueryStorageClient.splitReadStreamCallable().futureCall(request);
   // Do something
   SplitReadStreamResponse response = future.get();
 }

Returns
Type	Description
`UnaryCallable<SplitReadStreamRequest,SplitReadStreamResponse>`