Package org.pentaho.di.trans.steps.mergejoin

Class MergeJoin

java.lang.Object

org.pentaho.di.trans.step.BaseStep

org.pentaho.di.trans.steps.mergejoin.MergeJoin

All Implemented Interfaces:

org.pentaho.di.core.ExtensionDataInterface, HasLogChannelInterface, org.pentaho.di.core.logging.LoggingObjectInterface, org.pentaho.di.core.logging.LoggingObjectLifecycleInterface, org.pentaho.di.core.variables.VariableSpace, StepInterface

public class MergeJoin
extends BaseStep
implements StepInterface

Merge rows from 2 sorted streams and output joined rows with matched key fields. Use this instead of hash join is both your input streams are too big to fit in memory. Note that both the inputs must be sorted on the join key. This is a first prototype implementation that only handles two streams and inner join. It also always outputs all values from both streams. Ideally, we should: 1) Support any number of incoming streams 2) Allow user to choose the join type (inner, outer) for each stream 3) Allow user to choose which fields to push to next step 4) Have multiple output ports as follows: a) Containing matched records b) Unmatched records for each input port 5) Support incoming rows to be sorted either on ascending or descending order. The currently implementation only supports ascending

Since:

24-nov-2006

Author:

Biswapesh

Field Summary

Fields inherited from class org.pentaho.di.trans.step.BaseStep

deadLockCounter, extensionDataMap, first, linesInput, linesOutput, linesRead, linesRejected, linesSkipped, linesUpdated, linesWritten, log, metaStore, repository, rowListeners, safeStopped, terminator, terminator_rows, variables

Constructor Summary

Constructors

Constructor	Description
MergeJoin(StepMeta stepMeta, StepDataInterface stepDataInterface, int copyNr, TransMeta transMeta, Trans trans)

Method Summary

Modifier and Type	Method	Description
boolean	init(StepMetaInterface smi, StepDataInterface sdi)	Initialize and do work where other steps need to wait for...
protected boolean	isInputLayoutValid(org.pentaho.di.core.row.RowMetaInterface row1, org.pentaho.di.core.row.RowMetaInterface row2)	Checks whether incoming rows are join compatible.
boolean	processRow(StepMetaInterface smi, StepDataInterface sdi)	Perform the equivalent of processing one row.

Methods inherited from class org.pentaho.di.trans.step.BaseStep

addResultFile, addRowListener, addRowSetToInputRowSets, addRowSetToOutputRowSets, addStepListener, batchComplete, beforeStartProcessing, buildLog, canProcessOneRow, checkFeedback, cleanup, clearInputRowSets, clearOutputRowSets, closeQuietly, copyVariablesFrom, decrementLinesRead, decrementLinesWritten, dispatch, dispose, environmentSubstitute, environmentSubstitute, environmentSubstitute, fieldSubstitute, findInputRowSet, findInputRowSet, findOutputRowSet, findOutputRowSet, getBooleanValueOfVariable, getClusterSize, getContainerObjectId, getCopy, getCurrentInputRowSetNr, getCurrentOutputRowSetNr, getDispatcher, getErrorRowMeta, getErrors, getExtensionDataMap, getFilename, getFirstInputRowSet, getInputRowMeta, getInputRowSets, getLinesInput, getLinesOutput, getLinesRead, getLinesRejected, getLinesSkipped, getLinesUpdated, getLinesWritten, getLogChannel, getLogChannelId, getLogFields, getLogLevel, getMetaStore, getNextClassNr, getObjectCopy, getObjectId, getObjectName, getObjectRevision, getObjectType, getOutputRowSets, getParent, getParentVariableSpace, getPartitionID, getPartitionTargets, getPreviewRowMeta, getProcessed, getRegistrationDate, getRemoteInputSteps, getRemoteOutputSteps, getRepartitioning, getRepository, getRepositoryDirectory, getResultFiles, getRow, getRowFrom, getRowHandler, getRowListeners, getRuntime, getServerSockets, getSlaveNr, getSocketRepository, getStatus, getStatusDescription, getStepDataInterface, getStepID, getStepListeners, getStepMeta, getStepMetaInterface, getStepname, getTrans, getTransMeta, getTypeId, getUniqueStepCountAcrossSlaves, getUniqueStepNrAcrossSlaves, getVariable, getVariable, handleGetRowFrom, handlePutRowTo, identifyErrorOutput, incrementLinesInput, incrementLinesOutput, incrementLinesRead, incrementLinesRejected, incrementLinesSkipped, incrementLinesUpdated, incrementLinesWritten, initBeforeStart, initializeVariablesFrom, injectVariables, isBasic, isDebug, isDetailed, isDistributed, isForcingSeparateLogging, isGatheringMetrics, isInitialising, isMapping, isPartitioned, isPaused, isRowLevel, isRunning, isSafeStopped, isStopped, isUsingThreadPriorityManagment, listVariables, logBasic, logBasic, logDebug, logDebug, logDetailed, logDetailed, logError, logError, logError, logMinimal, logMinimal, logRowlevel, logRowlevel, logSummary, markStart, markStop, openRemoteInputStepSocketsOnce, openRemoteOutputStepSocketsOnce, outputIsDone, pauseRunning, putError, putRow, putRowTo, removeRowListener, resumeRunning, rowsetInputSize, rowsetOutputSize, safeModeChecking, safeModeChecking, setCarteObjectId, setCopy, setCurrentInputRowSetNr, setCurrentOutputRowSetNr, setDistributed, setErrorRowMeta, setErrors, setForcingSeparateLogging, setGatheringMetrics, setInputRowMeta, setInputRowSets, setInternalVariables, setLinesInput, setLinesOutput, setLinesRead, setLinesRejected, setLinesSkipped, setLinesUpdated, setLinesWritten, setLogLevel, setMetaStore, setOutputDone, setOutputRowSets, setParentVariableSpace, setPartitioned, setPartitionID, setPartitionTargets, setPaused, setPaused, setPreviewRowMeta, setRepartitioning, setRepository, setRowHandler, setRunning, setSafeStopped, setServerSockets, setSocketRepository, setStepDataInterface, setStepListeners, setStepMeta, setStepMetaInterface, setStepname, setStopped, setTransMeta, setUsingThreadPriorityManagment, setVariable, shareVariablesWith, stopAll, stopRunning, stopRunning, swapFirstInputRowSetIfExists, toString, verifyInputDeadLock, waitUntilTransformationIsStarted

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.pentaho.di.core.logging.LoggingObjectLifecycleInterface

callAfterLog, callBeforeLog

Methods inherited from interface org.pentaho.di.trans.step.StepInterface

addRowListener, addRowSetToInputRowSets, addRowSetToOutputRowSets, addStepListener, afterFinishProcessing, batchComplete, beforeStartProcessing, canProcessOneRow, cleanup, dispose, getCopy, getCurrentInputRowSetNr, getCurrentOutputRowSetNr, getErrors, getInputRowSets, getLinesInput, getLinesOutput, getLinesRead, getLinesRejected, getLinesUpdated, getLinesWritten, getLogChannel, getMetaStore, getOutputRowSets, getPartitionID, getProcessed, getRepository, getResultFiles, getRow, getRowListeners, getRuntime, getStatus, getStepID, getStepMeta, getStepname, getTrans, identifyErrorOutput, initBeforeStart, isMapping, isPartitioned, isPaused, isRunning, isSafeStopped, isStopped, isUsingThreadPriorityManagment, markStart, markStop, pauseRunning, putRow, removeRowListener, resumeRunning, rowsetInputSize, rowsetOutputSize, setCurrentInputRowSetNr, setCurrentOutputRowSetNr, setErrors, setLinesRejected, setMetaStore, setOutputDone, setPartitioned, setPartitionID, setRepartitioning, setRepository, setRunning, setSafeStopped, setStopped, setUsingThreadPriorityManagment, stopAll, stopRunning, subStatuses

Methods inherited from interface org.pentaho.di.core.variables.VariableSpace

copyVariablesFrom, environmentSubstitute, environmentSubstitute, environmentSubstitute, fieldSubstitute, getBooleanValueOfVariable, getParentVariableSpace, getVariable, getVariable, initializeVariablesFrom, injectVariables, listVariables, setParentVariableSpace, setVariable, shareVariablesWith

Constructor Details

MergeJoin

public MergeJoin(StepMeta stepMeta,
 StepDataInterface stepDataInterface,
 int copyNr,
 TransMeta transMeta,
 Trans trans)

Method Details

processRow

public boolean processRow(StepMetaInterface smi,
 StepDataInterface sdi)
                   throws org.pentaho.di.core.exception.KettleException

Description copied from interface: StepInterface

Perform the equivalent of processing one row. Typically this means reading a row from input (getRow()) and passing a row to output (putRow)).

Specified by:

processRow in interface StepInterface

Overrides:

processRow in class BaseStep

Parameters:

smi - The steps metadata to work with

sdi - The steps temporary working data to work with (database connections, result sets, caches, temporary variables, etc.)

Returns:

false if no more rows can be processed or an error occurred.

Throws:

org.pentaho.di.core.exception.KettleException

init

public boolean init(StepMetaInterface smi,
 StepDataInterface sdi)

Description copied from interface: StepInterface

Initialize and do work where other steps need to wait for...

Specified by:

init in interface StepInterface

Overrides:

init in class BaseStep

Parameters:

smi - The metadata to work with

sdi - The data to initialize

See Also:

• StepInterface.init(org.pentaho.di.trans.step.StepMetaInterface, org.pentaho.di.trans.step.StepDataInterface)

isInputLayoutValid

protected boolean isInputLayoutValid(org.pentaho.di.core.row.RowMetaInterface row1,
 org.pentaho.di.core.row.RowMetaInterface row2)

Checks whether incoming rows are join compatible. This essentially means that the keys being compared should be of the same datatype and both rows should have the same number of keys specified

Parameters:

row1 - Reference row

row2 - Row to compare to

Returns:

true when templates are compatible.