Package org.apache.beam.sdk.io.gcp.spanner.changestreams.action

Class HeartbeatRecordAction

java.lang.Object

org.apache.beam.sdk.io.gcp.spanner.changestreams.action.HeartbeatRecordAction

public class HeartbeatRecordAction
extends java.lang.Object

This class is part of the process for ReadChangeStreamPartitionDoFn SDF. It is responsible for processing HeartbeatRecords. The records will be used to progress the watermark for the current element (partition).

Method Summary

Modifier and Type	Method	Description
java.util.Optional<org.apache.beam.sdk.transforms.DoFn.ProcessContinuation>	run(PartitionMetadata partition, HeartbeatRecord record, org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker<TimestampRange,com.google.cloud.Timestamp> tracker, RestrictionInterrupter<com.google.cloud.Timestamp> interrupter, org.apache.beam.sdk.transforms.splittabledofn.ManualWatermarkEstimator<org.joda.time.Instant> watermarkEstimator)	This is the main processing function for a HeartbeatRecord.

Methods inherited from class java.lang.Object

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

Method Detail

run

public java.util.Optional<org.apache.beam.sdk.transforms.DoFn.ProcessContinuation> run(PartitionMetadata partition,
                                                                                       HeartbeatRecord record,
                                                                                       org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker<TimestampRange,com.google.cloud.Timestamp> tracker,
                                                                                       RestrictionInterrupter<com.google.cloud.Timestamp> interrupter,
                                                                                       org.apache.beam.sdk.transforms.splittabledofn.ManualWatermarkEstimator<org.joda.time.Instant> watermarkEstimator)

This is the main processing function for a HeartbeatRecord. It returns an Optional of DoFn.ProcessContinuation to indicate if the calling function should stop or not. If the Optional returned is empty, it means that the calling function can continue with the processing. If an Optional of DoFn.ProcessContinuation.stop() is returned, it means that this function was unable to claim the timestamp of the HeartbeatRecord, so the caller should stop. If an Optional of DoFn.ProcessContinuation.resume() is returned, it means that this function should not attempt to claim further timestamps of the HeartbeatRecord, but instead should commit what it has processed so far.

When processing the HeartbeatRecord the following procedure is applied:

1. We try to claim the heartbeat record timestamp. If it is not possible, we stop here and return.
2. We update the necessary metrics.
3. We update the watermark to the heartbeat record timestamp.