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Posted to issues@beam.apache.org by "Jeff Webb (Jira)" <ji...@apache.org> on 2021/09/14 23:23:00 UTC
[jira] [Updated] (BEAM-10596) Sharding with fileio.WriteToFiles
need to set `max_writers_per_bundle=0` when using InteractiveRunner or
DirectRunner?
[ https://issues.apache.org/jira/browse/BEAM-10596?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jeff Webb updated BEAM-10596:
-----------------------------
Status: Open (was: Triage Needed)
> Sharding with fileio.WriteToFiles need to set `max_writers_per_bundle=0` when using InteractiveRunner or DirectRunner?
> ----------------------------------------------------------------------------------------------------------------------
>
> Key: BEAM-10596
> URL: https://issues.apache.org/jira/browse/BEAM-10596
> Project: Beam
> Issue Type: Bug
> Components: sdk-py-core
> Affects Versions: 2.23.0
> Environment: - Python 3.7.6
> - `apache-beam==2.23.0`
> - Reproducing is done in GCP's jupyter notebook environment. https://cloud.google.com/dataflow/docs/guides/interactive-pipeline-development
> Reporter: gecko655
> Priority: P3
>
> h3. Description:
> `fileio.WriteToFiles` ignores the option `shards=3` given to its constructor unless I set `max_writers_per_bundle` to `0`.
> It reproduces with InteractiveRunner or DirectRunner, but does not reproduce with DataflowRunner.
> h3. Example:
> Suppose I have the following pipeline (with interactive runner):
> {code:python}
> import apache_beam as beam
> import apache_beam.io.fileio as fileio
> import apache_beam.runners.interactive.interactive_beam as ib
> user_ids = list(map(lambda x: 'user_id' + str(x), range(0, 10000)))
> with beam.Pipeline(InteractiveRunner()) as pipeline:
> user_list = pipeline | 'create pcollection' >> beam.Create(user_ids)
> write_sharded_csv = user_list | 'write sharded csv files' >> fileio.WriteToFiles(
> path='/tmp/data/',
> shards=3,
> file_naming=fileio.default_file_naming(prefix='userlist', suffix='.csv'),
> # max_writers_per_bundle=0,
> )
> ib.show(write_sharded_csv)
> {code}
> This pipeline is implemented to...
> - Creates PCollection of strings: 'user_id1', 'user_id2', ... 'user_id10000'
> - Writes the user ids to 3 local files with sharding.
> The code does not work as intended. It writes whole user ids to only 1 file.
> The code DOES work as intended after I added the `max_writers_per_bundle=0` argument to the `WriteToFiles` constructor.
> The code also works if I use GCP's DataflowRunner instead of InteractiveRunner.
> Is the behavior intentional or bug?
> I couldn't understand why `max_writers_per_bundle` is related to the sharding behavior. I couldn't find any documentation about this.
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