Class BigQueryStorageClient (2.44.1)

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:

1. 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.
2. 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.
3. 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);
 
 

Constructs an instance of BigQueryStorageClient with default 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.

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

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.

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);
 }
 

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);
 }
 

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();
 }
 

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);
 }
 

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 = "";
   int requestedStreams = 0;
   ReadSession response = bigQueryStorageClient.createReadSession(tableReference, parent, requestedStreams);
 }
 

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();
   ApiFuture<ReadSession> future = bigQueryStorageClient.createReadSessionCallable().futureCall(request);
   // Do something
   ReadSession response = future.get();
 }
 

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);
 }
 

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();
   bigQueryStorageClient.finalizeStream(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 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();
   ApiFuture<Void> future = bigQueryStorageClient.finalizeStreamCallable().futureCall(request);
   // Do something
   future.get();
 }
 

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
   }
 }
 

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);
 }
 

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();
   SplitReadStreamResponse response = bigQueryStorageClient.splitReadStream(originalStream);
 }
 

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();
   ApiFuture<SplitReadStreamResponse> future = bigQueryStorageClient.splitReadStreamCallable().futureCall(request);
   // Do something
   SplitReadStreamResponse response = future.get();
 }