org.apache.pig.backend.hadoop.executionengine.mapReduceLayer

Class Launcher

java.lang.Object

org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.Launcher

Direct Known Subclasses:

MapReduceLauncher

public abstract class Launcher
extends Object

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Launcher()

Method Summary

Methods

Modifier and Type	Method and Description
protected double	calculateProgress(org.apache.hadoop.mapred.jobcontrol.JobControl jc, org.apache.hadoop.mapred.JobClient jobClient) Compute the progress of the current job submitted through the JobControl object jc to the JobClient jobClient
protected long	computeTimeSpent(org.apache.hadoop.mapred.TaskReport[] taskReports)
abstract void	explain(PhysicalPlan pp, PigContext pc, PrintStream ps, String format, boolean verbose) Explain how a pig job will be executed on the underlying infrastructure.
protected void	getErrorMessages(org.apache.hadoop.mapred.TaskReport[] reports, String type, boolean errNotDbg, PigContext pigContext)
StackTraceElement	getStackTraceElement(String line)
protected void	getStats(org.apache.hadoop.mapred.jobcontrol.Job job, org.apache.hadoop.mapred.JobClient jobClient, boolean errNotDbg, PigContext pigContext)
long	getTotalHadoopTimeSpent()
protected boolean	isComplete(double prog)
abstract PigStats	launchPig(PhysicalPlan php, String grpName, PigContext pc) Method to launch pig for hadoop either for a cluster's job tracker or for a local job runner.
protected double	progressOfRunningJob(org.apache.hadoop.mapred.jobcontrol.Job j, org.apache.hadoop.mapred.JobClient jobClient) Returns the progress of a Job j which is part of a submitted JobControl object.
void	reset() Resets the state after a launch

Methods inherited from class java.lang.Object

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

Constructor Detail

Launcher

protected Launcher()

Method Detail

reset

public void reset()

Resets the state after a launch

launchPig

public abstract PigStats launchPig(PhysicalPlan php,
                 String grpName,
                 PigContext pc)
                            throws PlanException,
                                   VisitorException,
                                   IOException,
                                   ExecException,
                                   JobCreationException,
                                   Exception

Method to launch pig for hadoop either for a cluster's job tracker or for a local job runner. THe only difference between the two is the job client. Depending on the pig context the job client will be initialize to one of the two. Launchers for other frameworks can overide these methods. Given an input PhysicalPlan, it compiles it to get a MapReduce Plan. The MapReduce plan which has multiple MapReduce operators each one of which has to be run as a map reduce job with dependency information stored in the plan. It compiles the MROperPlan into a JobControl object. Each Map Reduce operator is converted into a Job and added to the JobControl object. Each Job also has a set of dependent Jobs that are created using the MROperPlan. The JobControl object is obtained from the JobControlCompiler Then a new thread is spawned that submits these jobs while respecting the dependency information. The parent thread monitors the submitted jobs' progress and after it is complete, stops the JobControl thread.

Parameters:

php -

grpName -

pc -

Throws:

PlanException

VisitorException

IOException

ExecException

JobCreationException

Exception

explain

public abstract void explain(PhysicalPlan pp,
           PigContext pc,
           PrintStream ps,
           String format,
           boolean verbose)
                      throws PlanException,
                             VisitorException,
                             IOException

Explain how a pig job will be executed on the underlying infrastructure.

Parameters:

pp - PhysicalPlan to explain

pc - PigContext to use for configuration

ps - PrintStream to write output on.

format - Format to write in

verbose - Amount of information to print

Throws:

VisitorException

IOException

PlanException

isComplete

protected boolean isComplete(double prog)

getStats

protected void getStats(org.apache.hadoop.mapred.jobcontrol.Job job,
            org.apache.hadoop.mapred.JobClient jobClient,
            boolean errNotDbg,
            PigContext pigContext)
                 throws Exception

Throws:

Exception

computeTimeSpent

protected long computeTimeSpent(org.apache.hadoop.mapred.TaskReport[] taskReports)

getErrorMessages

protected void getErrorMessages(org.apache.hadoop.mapred.TaskReport[] reports,
                    String type,
                    boolean errNotDbg,
                    PigContext pigContext)
                         throws Exception

Throws:

Exception

calculateProgress

protected double calculateProgress(org.apache.hadoop.mapred.jobcontrol.JobControl jc,
                       org.apache.hadoop.mapred.JobClient jobClient)
                            throws IOException

Compute the progress of the current job submitted through the JobControl object jc to the JobClient jobClient

Parameters:

jc - - The JobControl object that has been submitted

jobClient - - The JobClient to which it has been submitted

Returns:

The progress as a precentage in double format

Throws:

IOException

progressOfRunningJob

protected double progressOfRunningJob(org.apache.hadoop.mapred.jobcontrol.Job j,
                          org.apache.hadoop.mapred.JobClient jobClient)
                               throws IOException

Returns the progress of a Job j which is part of a submitted JobControl object. The progress is for this Job. So it has to be scaled down by the num of jobs that are present in the JobControl.

Parameters:

j - - The Job for which progress is required

jobClient - - the JobClient to which it has been submitted

Returns:

Returns the percentage progress of this Job

Throws:

IOException

getTotalHadoopTimeSpent

public long getTotalHadoopTimeSpent()

getStackTraceElement

public StackTraceElement getStackTraceElement(String line)
                                       throws Exception

Parameters:

line - the string representation of a stack trace returned by printStackTrace

Returns:

the StackTraceElement object representing the stack trace

Throws:

Exception