org.apache.hadoop.hive.ql.exec

Class TableScanOperator

java.lang.Object

org.apache.hadoop.hive.ql.exec.Operator<TableScanDesc>

org.apache.hadoop.hive.ql.exec.TableScanOperator

All Implemented Interfaces:

Serializable, Cloneable, Node

public class TableScanOperator
extends Operator<TableScanDesc>
implements Serializable

Table Scan Operator If the data is coming from the map-reduce framework, just forward it. This will be needed as part of local work when data is not being read as part of map-reduce framework

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.hive.ql.exec.Operator

Operator.OperatorFunc, Operator.State

Field Summary

Fields

Modifier and Type	Field and Description
protected org.apache.hadoop.mapred.JobConf	jc

Fields inherited from class org.apache.hadoop.hive.ql.exec.Operator

alias, childOperators, childOperatorsArray, childOperatorsTag, colExprMap, conf, CONTEXT_NAME_KEY, done, groupKeyObject, HIVECOUNTERCREATEDFILES, HIVECOUNTERFATAL, id, inputObjInspectors, isLogDebugEnabled, isLogInfoEnabled, isLogTraceEnabled, LOG, operatorId, out, outputObjInspector, parentOperators, PLOG, reporter, state, statsMap

Constructor Summary

Constructors

Constructor and Description
TableScanOperator()

Method Summary

Methods

Modifier and Type	Method and Description
void	cleanUpInputFileChangedOp()
Operator<? extends OperatorDesc>	clone()
void	closeOp(boolean abort) Operator specific close routine.
String	getName() The operator name for this operator type.
List<Integer>	getNeededColumnIDs()
List<String>	getNeededColumns()
static String	getOperatorName()
List<String>	getReferencedColumns()
TableDesc	getTableDesc()
OperatorType	getType() Return the type of the specific operator among the types in OperatorType.
protected Collection<Future<?>>	initializeOp(org.apache.hadoop.conf.Configuration hconf) Operator specific initialization.
void	process(Object row, int tag) Other than gathering statistics for the ANALYZE command, the table scan operator does not do anything special other than just forwarding the row.
void	setNeededColumnIDs(List<Integer> orign_columns)
void	setNeededColumns(List<String> columnNames)
void	setReferencedColumns(List<String> referencedColumns)
void	setTableDesc(TableDesc tableDesc)
boolean	supportAutomaticSortMergeJoin() Whether this operator supports automatic sort merge join.
boolean	supportSkewJoinOptimization()

Methods inherited from class org.apache.hadoop.hive.ql.exec.Operator

acceptLimitPushdown, allInitializedParentsAreClosed, areAllParentsInitialized, augmentPlan, cleanUpInputFileChanged, cloneOp, cloneRecursiveChildren, close, columnNamesRowResolvedCanBeObtained, completeInitializationOp, createDummy, defaultEndGroup, defaultStartGroup, dump, dump, endGroup, flush, forward, getAdditionalCounters, getChildOperators, getChildren, getColumnExprMap, getConf, getConfiguration, getDone, getExecContext, getGroupKeyObject, getIdentifier, getInputObjInspectors, getNextCntr, getNumChild, getNumParent, getOperatorId, getOpTraits, getOutputObjInspector, getParentOperators, getSchema, getStatistics, getStats, initEvaluators, initEvaluators, initEvaluatorsAndReturnStruct, initialize, initialize, initializeChildren, initializeLocalWork, initOperatorId, isUseBucketizedHiveInputFormat, jobClose, jobCloseOp, logStats, opAllowedAfterMapJoin, opAllowedBeforeMapJoin, opAllowedBeforeSortMergeJoin, opAllowedConvertMapJoin, passExecContext, preorderMap, processGroup, removeChild, removeChildAndAdoptItsChildren, removeChildren, removeParent, replaceChild, replaceParent, reset, resetId, resetStats, setAlias, setChildOperators, setColumnExprMap, setConf, setDone, setExecContext, setGroupKeyObject, setId, setInputContext, setInputObjInspectors, setOperatorId, setOpTraits, setOutputCollector, setParentOperators, setReporter, setSchema, setStatistics, setUseBucketizedHiveInputFormat, startGroup, supportUnionRemoveOptimization, toString, toString

Methods inherited from class java.lang.Object

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

Field Detail

jc

protected transient org.apache.hadoop.mapred.JobConf jc

Constructor Detail

TableScanOperator

public TableScanOperator()

Method Detail

getTableDesc

public TableDesc getTableDesc()

setTableDesc

public void setTableDesc(TableDesc tableDesc)

process

public void process(Object row,
           int tag)
             throws HiveException

Other than gathering statistics for the ANALYZE command, the table scan operator does not do anything special other than just forwarding the row. Since the table data is always read as part of the map-reduce framework by the mapper. But, when this assumption stops to be true, i.e table data won't be only read by the mapper, this operator will be enhanced to read the table.

Specified by:

process in class Operator<TableScanDesc>

Parameters:

row - The object representing the row.

tag - The tag of the row usually means which parent this row comes from. Rows with the same tag should have exactly the same rowInspector all the time.

Throws:

HiveException

cleanUpInputFileChangedOp

public void cleanUpInputFileChangedOp()
                               throws HiveException

Overrides:

cleanUpInputFileChangedOp in class Operator<TableScanDesc>

Throws:

HiveException

initializeOp

protected Collection<Future<?>> initializeOp(org.apache.hadoop.conf.Configuration hconf)
                                      throws HiveException

Description copied from class: Operator

Operator specific initialization.

Overrides:

initializeOp in class Operator<TableScanDesc>

Throws:

HiveException

closeOp

public void closeOp(boolean abort)
             throws HiveException

Description copied from class: Operator

Operator specific close routine. Operators which inherents this class should overwrite this funtion for their specific cleanup routine.

Overrides:

closeOp in class Operator<TableScanDesc>

Throws:

HiveException

getName

public String getName()

The operator name for this operator type. This is used to construct the rule for an operator

Specified by:

getName in interface Node

Overrides:

getName in class Operator<TableScanDesc>

Returns:

the operator name

getOperatorName

public static String getOperatorName()

setNeededColumnIDs

public void setNeededColumnIDs(List<Integer> orign_columns)

getNeededColumnIDs

public List<Integer> getNeededColumnIDs()

setNeededColumns

public void setNeededColumns(List<String> columnNames)

getNeededColumns

public List<String> getNeededColumns()

setReferencedColumns

public void setReferencedColumns(List<String> referencedColumns)

getReferencedColumns

public List<String> getReferencedColumns()

getType

public OperatorType getType()

Description copied from class: Operator

Return the type of the specific operator among the types in OperatorType.

Specified by:

getType in class Operator<TableScanDesc>

Returns:

OperatorType.*

supportSkewJoinOptimization

public boolean supportSkewJoinOptimization()

Overrides:

supportSkewJoinOptimization in class Operator<TableScanDesc>

supportAutomaticSortMergeJoin

public boolean supportAutomaticSortMergeJoin()

Description copied from class: Operator

Whether this operator supports automatic sort merge join. The stack is traversed, and this method is invoked for all the operators.

Overrides:

supportAutomaticSortMergeJoin in class Operator<TableScanDesc>

Returns:

TRUE if yes, FALSE otherwise.

clone

public Operator<? extends OperatorDesc> clone()
                                       throws CloneNotSupportedException

Overrides:

clone in class Operator<TableScanDesc>

Throws:

CloneNotSupportedException