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https://issues.apache.org/jira/browse/SPARK-28025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16862908#comment-16862908
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Stavros Kontopoulos edited comment on SPARK-28025 at 6/13/19 10:35 AM:
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I just found out that the following config options would suffice to avoid
creating crcs:
--conf
spark.hadoop.spark.sql.streaming.checkpointFileManagerClass=org.apache.spark.sql.execution.streaming.FileSystemBasedCheckpointFileManager
--conf spark.hadoop.fs.file.impl=org.apache.hadoop.fs.RawLocalFileSystem
So need to make a PR to disable crc emission if user wants to in this case but
could make one for the generic case. Btw there is a nice summary on the topic
in chapter 5 of the book: hadoop the definitive guide.
So should we clean up things like in the old PR? I am not sure if the old PR
would work with the LocalFs as it seems that the crc file will be renamed by
default.
was (Author: skonto):
I just found out that the following config options would suffice to avoid
creating crcs:
--conf
spark.hadoop.spark.sql.streaming.checkpointFileManagerClass=org.apache.spark.sql.execution.streaming.FileSystemBasedCheckpointFileManager
--conf spark.hadoop.fs.file.impl=org.apache.hadoop.fs.RawLocalFileSystem
So should we clean up things like in the old PR? I am not sure if the old PR
would work with the LocalFs as it seems that the crc file will be renamed by
default.
> HDFSBackedStateStoreProvider should not leak .crc files
> --------------------------------------------------------
>
> Key: SPARK-28025
> URL: https://issues.apache.org/jira/browse/SPARK-28025
> Project: Spark
> Issue Type: Bug
> Components: Structured Streaming
> Affects Versions: 2.4.3
> Environment: Spark 2.4.3
> Kubernetes 1.11(?) (OpenShift)
> StateStore storage on a mounted PVC. Viewed as a local filesystem by the
> `FileContextBasedCheckpointFileManager` :
> {noformat}
> scala> glusterfm.isLocal
> res17: Boolean = true{noformat}
> Reporter: Gerard Maas
> Priority: Major
>
> The HDFSBackedStateStoreProvider when using the default CheckpointFileManager
> is leaving '.crc' files behind. There's a .crc file created for each
> `atomicFile` operation of the CheckpointFileManager.
> Over time, the number of files becomes very large. It makes the state store
> file system constantly increase in size and, in our case, deteriorates the
> file system performance.
> Here's a sample of one of our spark storage volumes after 2 days of execution
> (4 stateful streaming jobs, each on a different sub-dir):
> #
> {noformat}
> Total files in PVC (used for checkpoints and state store)
> $find . | wc -l
> 431796
> # .crc files
> $find . -name "*.crc" | wc -l
> 418053{noformat}
> With each .crc file taking one storage block, the used storage runs into the
> GBs of data.
> These jobs are running on Kubernetes. Our shared storage provider, GlusterFS,
> shows serious performance deterioration with this large number of files:
> {noformat}
> DEBUG HDFSBackedStateStoreProvider: fetchFiles() took 29164ms{noformat}
>
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