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https://issues.apache.org/jira/browse/FLINK-9113?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16425196#comment-16425196
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ASF GitHub Bot commented on FLINK-9113:
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GitHub user twalthr opened a pull request:
https://github.com/apache/flink/pull/5811
[FLINK-9113] [connectors] Fix flushing behavior of bucketing sink for local
filesystems
## What is the purpose of the change
This PR changes the flushing behavior for HDFS' local filesystem
abstraction. See also FLINK-9113 for more details.
## Brief change log
- Use `hsync` for local filesystems
- Add method to disable the new behavior
- Additional check for verifying correct valid length files
## Verifying this change
This fix is difficult to verify as it requires a OS process that is killed
before syncing. I added a dedicated local filesystem test.
## Does this pull request potentially affect one of the following parts:
- Dependencies (does it add or upgrade a dependency): no
- The public API, i.e., is any changed class annotated with
`@Public(Evolving)`: no
- The serializers: no
- The runtime per-record code paths (performance sensitive): yes
- Anything that affects deployment or recovery: JobManager (and its
components), Checkpointing, Yarn/Mesos, ZooKeeper: no
- The S3 file system connector: no
## Documentation
- Does this pull request introduce a new feature? no
- If yes, how is the feature documented? JavaDocs
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/twalthr/flink FLINK-9113
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/flink/pull/5811.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #5811
----
commit 543f206f0e9e8415468f5d1092553754a8869fc7
Author: Timo Walther <twalthr@...>
Date: 2018-04-04T08:29:57Z
[FLINK-9113] [connectors] Fix flushing behavior of bucketing sink for local
filesystems
----
> Data loss in BucketingSink when writing to local filesystem
> -----------------------------------------------------------
>
> Key: FLINK-9113
> URL: https://issues.apache.org/jira/browse/FLINK-9113
> Project: Flink
> Issue Type: Bug
> Components: Streaming Connectors
> Reporter: Timo Walther
> Assignee: Timo Walther
> Priority: Major
>
> This issue is closely related to FLINK-7737. By default the bucketing sink
> uses HDFS's {{org.apache.hadoop.fs.FSDataOutputStream#hflush}} for
> performance reasons. However, this leads to data loss in case of TaskManager
> failures when writing to a local filesystem
> {{org.apache.hadoop.fs.LocalFileSystem}}. We should use {{hsync}} by default
> in local filesystem cases and make it possible to disable this behavior if
> needed.
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