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ASF GitHub Bot logged work on BEAM-9346: ---------------------------------------- Author: ASF GitHub Bot Created on: 16/Mar/20 19:03 Start Date: 16/Mar/20 19:03 Worklog Time Spent: 10m Work Description: aaltay commented on issue #11122: [BEAM-9346] Improve the efficiency of TFRecordIO URL: https://github.com/apache/beam/pull/11122#issuecomment-599709980 If this is a common pattern (another one from: https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/io/WriteFiles.java#L412), should this be abstracted out to happen in a single place? /cc @chamikaramj @kennknowles ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org Issue Time Tracking ------------------- Worklog Id: (was: 404186) Time Spent: 2.5h (was: 2h 20m) > TFRecordIO inefficient read from sideinput causing pipeline to be slow > ---------------------------------------------------------------------- > > Key: BEAM-9346 > URL: https://issues.apache.org/jira/browse/BEAM-9346 > Project: Beam > Issue Type: Improvement > Components: sdk-java-core > Reporter: Ban Piao > Assignee: Piotr Szuberski > Priority: Major > Labels: dataflow, easyfix, performance > Fix For: Not applicable > > Time Spent: 2.5h > Remaining Estimate: 0h > > In TFRecordIO, Reify.viewInGlobalWindow(input.apply(View.asList()), > ListCoder.of(resultCoder)) is an inefficient way of reading large set of side > input. > Pipeline can be sped up significantly by combinging the PCollection<ResultT> > to a single element PCollection<List<ResultT>>. > Sample code: > > https://github.com/apache/beam/blob/master/sdks/java/core/src/main/java/org/apache/beam/sdk/io/WriteFiles.java#L412 > from > ``` > return input > .getPipeline() > .apply(Reify.viewInGlobalWindow(input.apply(View.asList()), > ListCoder.of(resultCoder))); > ``` > to > ``` > return input.apply("ToList", Combine.globally(new ToListCombineFn<>())); > ``` > where ToListCombineFn is defined as > ``` > public static class ToListCombineFn<ResultT> extends CombineFn<ResultT, > List<ResultT>, List<ResultT>> { > @Override > public List<ResultT> createAccumulator() { > return new ArrayList<>(); > } > @Override > public List<ResultT> addInput(List<ResultT> mutableAccumulator, ResultT > input) { > mutableAccumulator.add(input); > return mutableAccumulator; > } > @Override > public List<ResultT> mergeAccumulators(Iterable<List<ResultT>> > accumulators) { > Iterator<List<ResultT>> iter = accumulators.iterator(); > if (!iter.hasNext()) { > return new ArrayList<>(); > } > List<ResultT> merged = iter.next(); > while (iter.hasNext()) { > merged.addAll(iter.next()); > } > return merged; > } > @Override > public List<ResultT> extractOutput(List<ResultT> accumulator) { > return accumulator; > } > } > ``` -- This message was sent by Atlassian Jira (v8.3.4#803005)