org.apache.hadoop.hive.ql.exec
Class FetchTask

java.lang.Object
  org.apache.hadoop.hive.ql.exec.Task<FetchWork>
      org.apache.hadoop.hive.ql.exec.FetchTask

All Implemented Interfaces:

Serializable, Node

public class FetchTask
extends Task<FetchWork>
implements Serializable

FetchTask implementation.

See Also:

Serialized Form

Nested Class Summary

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

Task.FeedType

Field Summary

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

BACKUP_COMMON_JOIN, backupChildrenTasks, backupTask, childTasks, clonedConf, COMMON_JOIN, conf, console, CONVERTED_LOCAL_MAPJOIN, CONVERTED_MAPJOIN, db, driverContext, feedSubscribers, id, initialized, isdone, jobID, LOCAL_MAPJOIN, NO_TAG, parentTasks, queryPlan, queued, started, taskCounters, taskHandle, taskTag, work

Constructor Summary

FetchTask()

Method Summary

void	clearFetch() Clear the Fetch Operator.
int	execute(DriverContext driverContext) This method is overridden in each Task.
boolean	fetch(ArrayList<String> res)
int	getMaxRows() Return the maximum number of rows returned by fetch.
String	getName() Gets the name of the node.
TableDesc	getTblDesc() Return the tableDesc of the fetchWork.
StageType	getType() Should be overridden to return the type of the specific task among the types in StageType.
void	initialize(HiveConf conf, QueryPlan queryPlan, DriverContext ctx)
protected void	localizeMRTmpFilesImpl(Context ctx) If this task uses any map-reduce intermediate data (either for reading or for writing), localize them (using the supplied Context).
void	setMaxRows(int maxRows) Set the maximum number of rows returned by fetch.

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

addDependentTask, cloneConf, done, executeTask, getAndInitBackupTask, getBackupChildrenTasks, getBackupTask, getChildren, getChildTasks, getCounters, getDependentTasks, getFeedSubscribers, getId, getInitialized, getJobID, getParentTasks, getQueryPlan, getQueued, getReducer, getResultSchema, getTaskTag, getTopOperators, getWork, hasReduce, ifRetryCmdWhenFail, isLocalMode, isMapRedLocalTask, isMapRedTask, isRunnable, localizeMRTmpFiles, pushFeed, receiveFeed, removeDependentTask, removeFromChildrenTasks, requireLock, setBackupChildrenTasks, setBackupTask, setChildTasks, setDone, setFeedSubscribers, setId, setInitialized, setLocalMode, setParentTasks, setQueryPlan, setQueued, setRetryCmdWhenFail, setStarted, setTaskTag, setWork, started, subscribeFeed

Methods inherited from class java.lang.Object

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

Constructor Detail

FetchTask

public FetchTask()

Method Detail

initialize

public void initialize(HiveConf conf,
                       QueryPlan queryPlan,
                       DriverContext ctx)

Overrides:

initialize in class Task<FetchWork>

execute

public int execute(DriverContext driverContext)

Description copied from class: Task

This method is overridden in each Task. TODO execute should return a TaskHandle.

Specified by:

execute in class Task<FetchWork>

Returns:

status of executing the task

getTblDesc

public TableDesc getTblDesc()

Return the tableDesc of the fetchWork.

getMaxRows

public int getMaxRows()

Return the maximum number of rows returned by fetch.

setMaxRows

public void setMaxRows(int maxRows)

Set the maximum number of rows returned by fetch.

fetch

public boolean fetch(ArrayList<String> res)
              throws IOException,
                     CommandNeedRetryException

Overrides:

fetch in class Task<FetchWork>

Throws:

IOException

CommandNeedRetryException

getType

public StageType getType()

Description copied from class: Task

Should be overridden to return the type of the specific task among the types in StageType.

Specified by:

getType in class Task<FetchWork>

Returns:

StageType.* or null if not overridden

getName

public String getName()

Description copied from interface: Node

Gets the name of the node. This is used in the rule dispatchers.

Specified by:

getName in interface Node

Returns:

String

localizeMRTmpFilesImpl

protected void localizeMRTmpFilesImpl(Context ctx)

Description copied from class: Task

If this task uses any map-reduce intermediate data (either for reading or for writing), localize them (using the supplied Context). Map-Reduce intermediate directories are allocated using Context.getMRTmpFileURI() and can be localized using localizeMRTmpFileURI(). This method is declared abstract to force any task code to explicitly deal with this aspect of execution.

Specified by:

localizeMRTmpFilesImpl in class Task<FetchWork>

Parameters:

ctx - context object with which to localize

clearFetch

public void clearFetch()
                throws HiveException

Clear the Fetch Operator.

Throws:

HiveException