johnyangk closed pull request #142: [NEMO-257] Local combining only for
BinaryCombineFn
URL: https://github.com/apache/incubator-nemo/pull/142
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diff --git
a/compiler/frontend/beam/src/main/java/org/apache/nemo/compiler/frontend/beam/PipelineTranslator.java
b/compiler/frontend/beam/src/main/java/org/apache/nemo/compiler/frontend/beam/PipelineTranslator.java
index 7dc7af65a..d596f9f1a 100644
---
a/compiler/frontend/beam/src/main/java/org/apache/nemo/compiler/frontend/beam/PipelineTranslator.java
+++
b/compiler/frontend/beam/src/main/java/org/apache/nemo/compiler/frontend/beam/PipelineTranslator.java
@@ -58,7 +58,6 @@
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.BiFunction;
import java.util.stream.Collectors;
-import java.util.stream.Stream;
/**
* Converts DAG of Beam root to Nemo IR DAG.
@@ -314,23 +313,12 @@ private static void topologicalTranslator(final
TranslationContext ctx,
private static void combineTranslator(final TranslationContext ctx,
final CompositeTransformVertex
transformVertex,
final PTransform<?, ?> transform) {
- // No optimization for BeamSQL that handles Beam 'Row's.
- final boolean handlesBeamRow = Stream
- .concat(transformVertex.getNode().getInputs().values().stream(),
- transformVertex.getNode().getOutputs().values().stream())
- .map(pValue -> (KvCoder) getCoder(pValue, ctx.root)) // Input and output
of combine should be KV
- .map(kvCoder -> kvCoder.getValueCoder().getEncodedTypeDescriptor()) //
We're interested in the 'Value' of KV
- .anyMatch(valueTypeDescriptor ->
TypeDescriptor.of(Row.class).equals(valueTypeDescriptor));
- if (handlesBeamRow) {
- transformVertex.getDAG().topologicalDo(ctx::translate);
- return; // return early and give up optimization - TODO #209: Enable
Local Combiner for BeamSQL
- }
-
- // Local combiner optimization
final List<TransformVertex> topologicalOrdering =
transformVertex.getDAG().getTopologicalSort();
final TransformVertex groupByKeyBeamTransform = topologicalOrdering.get(0);
final TransformVertex last =
topologicalOrdering.get(topologicalOrdering.size() - 1);
- if (groupByKeyBeamTransform.getNode().getTransform() instanceof
GroupByKey) {
+ if (groupByKeyBeamTransform.getNode().getTransform() instanceof GroupByKey
+ && isBinaryCombine(extractCombineFn(transform))) {
+ // Local combiner optimization (only for binary combiners that are
guaranteed to be commutative/associative)
// Translate the given CompositeTransform under OneToOneEdge-enforced
context.
final TranslationContext oneToOneEdgeContext = new
TranslationContext(ctx,
OneToOneCommunicationPatternSelector.INSTANCE);
@@ -349,10 +337,30 @@ private static void combineTranslator(final
TranslationContext ctx,
// Translate the remaining vertices.
topologicalOrdering.stream().skip(1).forEach(ctx::translate);
} else {
+ // No optimization
transformVertex.getDAG().topologicalDo(ctx::translate);
}
}
+ private static boolean isBinaryCombine(final CombineFnBase.GlobalCombineFn
combineFn) {
+ return combineFn instanceof Combine.BinaryCombineFn
+ || combineFn instanceof Combine.BinaryCombineDoubleFn
+ || combineFn instanceof Combine.BinaryCombineIntegerFn
+ || combineFn instanceof Combine.BinaryCombineLongFn;
+ }
+
+ private static CombineFnBase.GlobalCombineFn extractCombineFn(final
PTransform<?, ?> combine) {
+ if (combine instanceof Combine.Globally) {
+ return ((Combine.Globally) combine).getFn();
+ } else if (combine instanceof Combine.PerKey) {
+ return ((Combine.PerKey) combine).getFn();
+ } else if (combine instanceof Combine.GroupedValues) {
+ return ((Combine.GroupedValues) combine).getFn();
+ } else {
+ throw new IllegalStateException(combine.toString());
+ }
+ }
+
/**
* Pushes the loop vertex to the stack before translating the inner DAG, and
pops it after the translation.
*
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