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https://issues.apache.org/jira/browse/BEAM-7013?focusedWorklogId=295598&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-295598
]
ASF GitHub Bot logged work on BEAM-7013:
----------------------------------------
Author: ASF GitHub Bot
Created on: 15/Aug/19 17:21
Start Date: 15/Aug/19 17:21
Worklog Time Spent: 10m
Work Description: robinyqiu commented on pull request #9144: [BEAM-7013]
Integrating ZetaSketch's HLL++ algorithm with Beam
URL: https://github.com/apache/beam/pull/9144#discussion_r314412303
##########
File path:
sdks/java/extensions/zetasketch/src/main/java/org/apache/beam/sdk/extensions/zetasketch/HllCountMergePartialFn.java
##########
@@ -44,109 +37,55 @@ private HllCountMergePartialFn() {}
return new HllCountMergePartialFn();
}
- /**
- * Accumulator for the {@link HllCount.MergePartial} combiner. Cannot use
{@link
- * HyperLogLogPlusPlus} directly because we need an "identity element" for
the {@code merge}
- * operation, and we are not able to create such "identity element" of type
{@link
- * HyperLogLogPlusPlus} without knowing the sketch precision and value type.
- */
- static final class HyperLogLogPlusPlusWrapper<T> {
- @Nullable private HyperLogLogPlusPlus<T> hll;
-
- private HyperLogLogPlusPlusWrapper(@Nullable HyperLogLogPlusPlus<T> hll) {
- this.hll = hll;
- }
- }
-
- /**
- * Coder for the {@link HyperLogLogPlusPlusWrapper} class with generic type
parameter {@code T}.
- */
- private static final class HyperLogLogPlusPlusWrapperCoder<T>
- extends AtomicCoder<HyperLogLogPlusPlusWrapper<T>> {
-
- private static final HyperLogLogPlusPlusWrapperCoder<?> INSTANCE =
- new HyperLogLogPlusPlusWrapperCoder<>();
-
- private final Coder<HyperLogLogPlusPlus<T>> nullableHllCoder =
- NullableCoder.of(HyperLogLogPlusPlusCoder.of());
-
- // Generic singleton factory pattern; the coder works for all
HyperLogLogPlusPlusWrapper objects
- // at runtime regardless of type T
- @SuppressWarnings("unchecked")
- static <T> HyperLogLogPlusPlusWrapperCoder<T> of() {
- return (HyperLogLogPlusPlusWrapperCoder<T>) INSTANCE;
- }
-
- @Override
- public void encode(HyperLogLogPlusPlusWrapper<T> value, OutputStream
outStream)
- throws IOException {
- nullableHllCoder.encode(value.hll, outStream);
- }
-
- @Override
- public HyperLogLogPlusPlusWrapper<T> decode(InputStream inStream) throws
IOException {
- return new
HyperLogLogPlusPlusWrapper<T>(nullableHllCoder.decode(inStream));
- }
-
- @Override
- public void verifyDeterministic() throws NonDeterministicException {
- nullableHllCoder.verifyDeterministic();
- }
- }
-
@Override
- public Coder<HyperLogLogPlusPlusWrapper<T>> getAccumulatorCoder(
+ public Coder<HyperLogLogPlusPlus<T>> getAccumulatorCoder(
CoderRegistry registry, Coder<byte[]> inputCoder) {
- return HyperLogLogPlusPlusWrapperCoder.of();
+ return NullableCoder.of(HyperLogLogPlusPlusCoder.of());
}
@Override
- public HyperLogLogPlusPlusWrapper<T> createAccumulator() {
- return new HyperLogLogPlusPlusWrapper<>(null);
+ public HyperLogLogPlusPlus<T> createAccumulator() {
+ return null;
}
@Override
- public HyperLogLogPlusPlusWrapper<T> addInput(
- HyperLogLogPlusPlusWrapper<T> accumulator, byte[] input) {
- if (accumulator.hll == null) {
+ public HyperLogLogPlusPlus<T> addInput(HyperLogLogPlusPlus<T> accumulator,
byte[] input) {
+ if (accumulator == null) {
@SuppressWarnings("unchecked")
- HyperLogLogPlusPlus<T> hll = (HyperLogLogPlusPlus<T>)
HyperLogLogPlusPlus.forProto(input);
- accumulator.hll = hll;
+ HyperLogLogPlusPlus<T> result = (HyperLogLogPlusPlus<T>)
HyperLogLogPlusPlus.forProto(input);
+ return result;
} else {
- accumulator.hll.merge(input);
+ accumulator.merge(input);
+ return accumulator;
}
- return accumulator;
}
@Override
- public HyperLogLogPlusPlusWrapper<T> mergeAccumulators(
- Iterable<HyperLogLogPlusPlusWrapper<T>> accumulators) {
- HyperLogLogPlusPlusWrapper<T> merged = createAccumulator();
- for (HyperLogLogPlusPlusWrapper<T> accumulator : accumulators) {
- if (accumulator.hll == null) {
+ public HyperLogLogPlusPlus<T>
mergeAccumulators(Iterable<HyperLogLogPlusPlus<T>> accumulators) {
+ HyperLogLogPlusPlus<T> merged = createAccumulator();
Review comment:
They are functionally equivalent. Calls `createAccumulator()` because
basically every implementation of `mergeAccumulators()` will start with that
(so it's like a paradigm?). Would leave it as it is.
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Issue Time Tracking
-------------------
Worklog Id: (was: 295598)
Time Spent: 19h 10m (was: 19h)
> A new count distinct transform based on BigQuery compatible HyperLogLog++
> implementation
> ----------------------------------------------------------------------------------------
>
> Key: BEAM-7013
> URL: https://issues.apache.org/jira/browse/BEAM-7013
> Project: Beam
> Issue Type: New Feature
> Components: extensions-java-sketching, sdk-java-core
> Reporter: Yueyang Qiu
> Assignee: Yueyang Qiu
> Priority: Major
> Fix For: 2.16.0
>
> Time Spent: 19h 10m
> Remaining Estimate: 0h
>
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