com.aliyun.odps.storage.read

Class InstanceReadSession

java.lang.Object

com.aliyun.odps.storage.read.InstanceReadSession

public class InstanceReadSession
extends Object

Implementation of a read session for the MaxCompute Storage API for Instances.

This class represents a read session for a MaxCompute Instance result, allowing clients to read data in a distributed manner using input splits. Each session is associated with a specific instance and provides methods to get the session ID, Arrow schema, and input splits for parallel processing.

Example usage:

 InstanceIdentifier instanceId = InstanceIdentifier.of("my_project", "my_instance_id");
 try (InstanceReadSession session = client.createInstanceReadSession(instanceId)) {
     List<InputSplit> splits = session.getSplits();
     for (InputSplit split : splits) {
         try (MaxInstanceArrowReader reader = session.createArrowReaderBuilder(split).build()) {
             // Process data from reader
         }
     }
 }
 

Constructor Summary

Constructors

Constructor and Description
InstanceReadSession(StorageStub storageStub, InstanceIdentifier instanceId, org.apache.arrow.memory.BufferAllocator allocator, CreateInstanceReadSessionResponse response) Constructs a new InstanceReadSession with the provided parameters.

Method Summary

Modifier and Type	Method and Description
InstanceReaderBuilder	createReaderBuilder() Creates a new builder for an Arrow reader for the specified input split.
org.apache.arrow.vector.types.pojo.Schema	getArrowSchema() Gets the Arrow schema for the data in this read session.
String	getId() Gets the unique identifier of this read session.
long	getRecordCount()
TableSchema	getTableSchema()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

InstanceReadSession

public InstanceReadSession(StorageStub storageStub,
                           InstanceIdentifier instanceId,
                           org.apache.arrow.memory.BufferAllocator allocator,
                           CreateInstanceReadSessionResponse response)

Constructs a new InstanceReadSession with the provided parameters.

Parameters:

storageStub - The storage stub for communicating with the MaxCompute service

instanceId - The identifier of the instance to read from

allocator - The buffer allocator for Arrow memory management

response - The response from the create instance read session API call

Method Detail

getId

public String getId()

Gets the unique identifier of this read session.

Returns:

The session ID

getArrowSchema

public org.apache.arrow.vector.types.pojo.Schema getArrowSchema()

Gets the Arrow schema for the data in this read session.

This method converts the MaxCompute table schema to an Arrow schema, which is used for efficient data processing and columnar format support.

Returns:

The Arrow schema representation of the instance data

getTableSchema

public TableSchema getTableSchema()

getRecordCount

public long getRecordCount()

createReaderBuilder

public InstanceReaderBuilder createReaderBuilder()

Creates a new builder for an Arrow reader for the specified input split.

This method initializes an Arrow reader builder that can be configured with various options before creating the actual Arrow reader. The reader allows reading data from a specific input split in Arrow format.

Returns:

A new InstanceReaderBuilder instance to configure the Arrow reader