[GitHub] [beam] damccorm opened a new issue, #20952: Implement destination-dependent sharding in FileIO.writeDynamic

[GitBox <gi...@apache.org>]

damccorm opened a new issue, #20952:
URL: https://github.com/apache/beam/issues/20952

   Destination dependent sharding feature is very much needed in order to maintain manageable files sizes and file counts in google storage especially when data volumes are very large.
   
   Current implementation doesn't allow that (per documentation ) [https://beam.apache.org/releases/javadoc/2.4.0/org/apache/beam/sdk/io/FileIO.html](https://beam.apache.org/releases/javadoc/2.4.0/org/apache/beam/sdk/io/FileIO.html)
   
    
   
   _*Note that currently sharding can not be destination-dependent: every window/pane for every destination will use the same number of shards specified via [`FileIO.Write.withNumShards(int)`|https://beam.apache.org/releases/javadoc/2.4.0/org/apache/beam/sdk/io/FileIO.Write.html#withNumShards-int-] or [`FileIO.Write.withSharding(org.apache.beam.sdk.transforms.PTransform<org.apache.beam.sdk.values.PCollection<UserT>, org.apache.beam.sdk.values.PCollectionView<java.lang.Integer>>)`|https://beam.apache.org/releases/javadoc/2.4.0/org/apache/beam/sdk/io/FileIO.Write.html#withSharding-org.apache.beam.sdk.transforms.PTransform-].*_
   
    
   
   **We use it as follows and end up with either very small or very large files per destination in the same window. Large files are not possible to open/process and small files clutter the bucket.
   
   ```
   
   Pipeline pipeline = Pipeline.create(options);
    pipeline.apply("Read PubSub Events", PubsubIO.readMessagesWithAttributes().fromSubscription(options.getInputSubscription()))
   
   .apply(options.getWindowDuration() + " Window",
    Window.<PubsubMessage>into(FixedWindows.of(parseDuration(options.getWindowDuration())))
   
   .triggering(AfterWatermark.pastEndOfWindow()) 
    .discardingFiredPanes()
    .withAllowedLateness(parseDuration("24h")).triggering(Repeatedly.forever(AfterWatermark.pastEndOfWindow())))
   
   .apply(FileIO.<String,PubsubMessage>writeDynamic()
   
   .by(new datePartition(options.getOutputFilenamePrefix(), options.getTimestampName()))
    .via(Contextful.fn(
   
   (SerializableFunction<PubsubMessage, String>) inputMsg -> new String(inputMsg.getPayload(), StandardCharsets.UTF_8)),
   
   TextIO.sink())
    .withDestinationCoder(StringUtf8Coder.of())
    .to(options.getOutputDirectory())
    .withNaming(type
   -> new CrowdStrikeFileNaming(type))
    .withNumShards(options.getNumShards())
    .withTempDirectory(options.getTempLocation()));
   
   pipeline.run();
   
   ```
     
   
   Imported from Jira [BEAM-12279](https://issues.apache.org/jira/browse/BEAM-12279). Original Jira may contain additional context.
   Reported by: inessa@cyber.nyc.gov.


-- 
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.

To unsubscribe, e-mail: github-unsubscribe@beam.apache.org.apache.org

For queries about this service, please contact Infrastructure at:
users@infra.apache.org