org.apache.flink.table.runtime.operators.join.temporal

Class TemporalRowTimeJoinOperator

java.lang.Object

org.apache.flink.streaming.api.operators.AbstractStreamOperator<org.apache.flink.table.data.RowData>

org.apache.flink.table.runtime.operators.join.temporal.BaseTwoInputStreamOperatorWithStateRetention

org.apache.flink.table.runtime.operators.join.temporal.TemporalRowTimeJoinOperator

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.state.CheckpointListener, org.apache.flink.streaming.api.operators.KeyContext, org.apache.flink.streaming.api.operators.KeyContextHandler, org.apache.flink.streaming.api.operators.SetupableStreamOperator<org.apache.flink.table.data.RowData>, org.apache.flink.streaming.api.operators.StreamOperator<org.apache.flink.table.data.RowData>, org.apache.flink.streaming.api.operators.StreamOperatorStateHandler.CheckpointedStreamOperator, org.apache.flink.streaming.api.operators.Triggerable<Object,org.apache.flink.runtime.state.VoidNamespace>, org.apache.flink.streaming.api.operators.TwoInputStreamOperator<org.apache.flink.table.data.RowData,org.apache.flink.table.data.RowData,org.apache.flink.table.data.RowData>

public class TemporalRowTimeJoinOperator
extends BaseTwoInputStreamOperatorWithStateRetention

The operator for temporal join (FOR SYSTEM_TIME AS OF o.rowtime) on row time, it has no limitation about message types of the left input and right input, this means the operator deals changelog well.

For Event-time temporal join, its probe side is a regular table, its build side is a versioned table, the version of versioned table can extract from the build side state. This operator works by keeping on the state collection of probe and build records to process on next watermark. The idea is that between watermarks we are collecting those elements and once we are sure that there will be no updates we emit the correct result and clean up the expired data in state.

Cleaning up the state drops all of the "old" values from the probe side, where "old" is defined as older then the current watermark. Build side is also cleaned up in the similar fashion, however we always keep at least one record - the latest one - even if it's past the last watermark.

One more trick is how the emitting results and cleaning up is triggered. It is achieved by registering timers for the keys. We could register a timer for every probe and build side element's event time (when watermark exceeds this timer, that's when we are emitting and/or cleaning up the state). However this would cause huge number of registered timers. For example with following evenTimes of probe records accumulated: {1, 2, 5, 8, 9}, if we had received Watermark(10), it would trigger 5 separate timers for the same key. To avoid that we always keep only one single registered timer for any given key, registered for the minimal value. Upon triggering it, we process all records with event times older then or equal to currentWatermark.

See Also:

Serialized Form

Field Summary

Fields inherited from class org.apache.flink.table.runtime.operators.join.temporal.BaseTwoInputStreamOperatorWithStateRetention

stateCleaningEnabled

Fields inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

chainingStrategy, config, lastRecordAttributes1, lastRecordAttributes2, latencyStats, LOG, metrics, output, processingTimeService

Constructor Summary

Constructors

Constructor and Description
TemporalRowTimeJoinOperator(InternalTypeInfo<org.apache.flink.table.data.RowData> leftType, InternalTypeInfo<org.apache.flink.table.data.RowData> rightType, GeneratedJoinCondition generatedJoinCondition, int leftTimeAttribute, int rightTimeAttribute, long minRetentionTime, long maxRetentionTime, boolean isLeftOuterJoin)

Method Summary

Modifier and Type	Method and Description
void	cleanupState(long time) The method to be called when a cleanup timer fires.
void	close()
void	onEventTime(org.apache.flink.streaming.api.operators.InternalTimer<Object,org.apache.flink.runtime.state.VoidNamespace> timer)
void	open()
void	processElement1(org.apache.flink.streaming.runtime.streamrecord.StreamRecord<org.apache.flink.table.data.RowData> element)
void	processElement2(org.apache.flink.streaming.runtime.streamrecord.StreamRecord<org.apache.flink.table.data.RowData> element)

Methods inherited from class org.apache.flink.table.runtime.operators.join.temporal.BaseTwoInputStreamOperatorWithStateRetention

cleanupLastTimer, onProcessingTime, registerProcessingCleanupTimer

Methods inherited from class org.apache.flink.streaming.api.operators.AbstractStreamOperator

finish, getChainingStrategy, getContainingTask, getCurrentKey, getExecutionConfig, getInternalTimerService, getKeyedStateBackend, getKeyedStateStore, getMetricGroup, getOperatorConfig, getOperatorID, getOperatorName, getOperatorStateBackend, getOrCreateKeyedState, getPartitionedState, getPartitionedState, getProcessingTimeService, getRuntimeContext, getTimeServiceManager, getUserCodeClassloader, hasKeyContext1, hasKeyContext2, initializeState, initializeState, isUsingCustomRawKeyedState, notifyCheckpointAborted, notifyCheckpointComplete, prepareSnapshotPreBarrier, processLatencyMarker, processLatencyMarker1, processLatencyMarker2, processRecordAttributes, processRecordAttributes1, processRecordAttributes2, processWatermark, processWatermark1, processWatermark2, processWatermarkStatus, processWatermarkStatus1, processWatermarkStatus2, reportOrForwardLatencyMarker, setChainingStrategy, setCurrentKey, setKeyContextElement1, setKeyContextElement2, setProcessingTimeService, setup, snapshotState, snapshotState

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.flink.streaming.api.operators.TwoInputStreamOperator

processLatencyMarker1, processLatencyMarker2, processRecordAttributes1, processRecordAttributes2, processWatermark1, processWatermark2, processWatermarkStatus1, processWatermarkStatus2

Methods inherited from interface org.apache.flink.streaming.api.operators.StreamOperator

finish, getMetricGroup, getOperatorID, initializeState, prepareSnapshotPreBarrier, setKeyContextElement1, setKeyContextElement2, snapshotState

Methods inherited from interface org.apache.flink.api.common.state.CheckpointListener

notifyCheckpointAborted, notifyCheckpointComplete

Methods inherited from interface org.apache.flink.streaming.api.operators.KeyContext

getCurrentKey, setCurrentKey

Methods inherited from interface org.apache.flink.streaming.api.operators.KeyContextHandler

hasKeyContext

Constructor Detail

TemporalRowTimeJoinOperator

public TemporalRowTimeJoinOperator(InternalTypeInfo<org.apache.flink.table.data.RowData> leftType,
                                   InternalTypeInfo<org.apache.flink.table.data.RowData> rightType,
                                   GeneratedJoinCondition generatedJoinCondition,
                                   int leftTimeAttribute,
                                   int rightTimeAttribute,
                                   long minRetentionTime,
                                   long maxRetentionTime,
                                   boolean isLeftOuterJoin)

Method Detail

open

public void open()
          throws Exception

Specified by:

open in interface org.apache.flink.streaming.api.operators.StreamOperator<org.apache.flink.table.data.RowData>

Overrides:

open in class BaseTwoInputStreamOperatorWithStateRetention

Throws:

Exception

processElement1

public void processElement1(org.apache.flink.streaming.runtime.streamrecord.StreamRecord<org.apache.flink.table.data.RowData> element)
                     throws Exception

Throws:

Exception

processElement2

public void processElement2(org.apache.flink.streaming.runtime.streamrecord.StreamRecord<org.apache.flink.table.data.RowData> element)
                     throws Exception

Throws:

Exception

onEventTime

public void onEventTime(org.apache.flink.streaming.api.operators.InternalTimer<Object,org.apache.flink.runtime.state.VoidNamespace> timer)
                 throws Exception

Throws:

Exception

close

public void close()
           throws Exception

Specified by:

close in interface org.apache.flink.streaming.api.operators.StreamOperator<org.apache.flink.table.data.RowData>

Overrides:

close in class org.apache.flink.streaming.api.operators.AbstractStreamOperator<org.apache.flink.table.data.RowData>

Throws:

Exception

cleanupState

public void cleanupState(long time)

The method to be called when a cleanup timer fires.

Specified by:

cleanupState in class BaseTwoInputStreamOperatorWithStateRetention

Parameters:

time - The timestamp of the fired timer.