Package org.apache.nemo.compiler.backend.nemo

Class NemoPlanRewriter

java.lang.Object

org.apache.nemo.compiler.backend.nemo.NemoPlanRewriter

All Implemented Interfaces:

PlanRewriter

public final class NemoPlanRewriter
extends Object
implements PlanRewriter

Rewrites the physical plan during execution, to enforce the optimizations of Nemo RunTimePasses.

A high-level flow of a rewrite is as follows: Runtime - (PhysicalPlan-level info) - NemoPlanRewriter - (IRDAG-level info) - NemoOptimizer - (new IRDAG) - NemoPlanRewriter - (new PhysicalPlan) - Runtime

Here, the NemoPlanRewriter acts as a translator between the Runtime that only understands PhysicalPlan-level info, and the NemoOptimizer that only understands IRDAG-level info.

This decoupling between the NemoOptimizer and the Runtime lets Nemo optimization policies dynamically control distributed execution behaviors, and at the same time enjoy correctness/reusability/composability properties that the IRDAG abstraction provides.

Constructor Summary

Constructors

Constructor	Description
NemoPlanRewriter(NemoOptimizer nemoOptimizer, NemoBackend nemoBackend)

Method Summary

Modifier and Type	Method	Description
void	accumulate(int messageId, Object data)
PhysicalPlan	rewrite(PhysicalPlan currentPhysicalPlan, int messageId)
void	setIRDAG(IRDAG irdag)

Methods inherited from class java.lang.Object

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

Constructor Detail

NemoPlanRewriter

@Inject
public NemoPlanRewriter(NemoOptimizer nemoOptimizer,
                        NemoBackend nemoBackend)

Method Detail

setIRDAG

public void setIRDAG(IRDAG irdag)

rewrite

public PhysicalPlan rewrite(PhysicalPlan currentPhysicalPlan,
                            int messageId)

Specified by:

rewrite in interface PlanRewriter

Parameters:

currentPhysicalPlan - to rewrite.

messageId - of the rewrite.

Returns:

physical plan.

accumulate

public void accumulate(int messageId,
                       Object data)

Specified by:

accumulate in interface PlanRewriter

Parameters:

messageId - of the rewrite.

data - to accumulate.