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https://issues.apache.org/jira/browse/SPARK-28025?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16862339#comment-16862339
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Stavros Kontopoulos edited comment on SPARK-28025 at 6/12/19 6:17 PM:
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There is a workaround by setting `--conf
spark.hadoop.spark.sql.streaming.checkpointFileManagerClass=org.apache.spark.sql.execution.streaming.FileSystemBasedCheckpointFileManager`
when using local fs
and modifying the FileSystemBasedCheckpointFileManager to run
`fs.setWriteChecksum(false)` after fs is created.
Reason is the FileContextBasedCheckpointFileManager will use ChecksumFS
([https://github.com/apache/hadoop/blob/73746c5da76d5e39df131534a1ec35dfc5d2529b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFs.java])
under the hoods which will ignore "
CreateOpts.checksumParam(ChecksumOpt.createDisabled())" passed. These settings
will only avoid creating checksums for the checksums themshelves.
FileSystemBasedCheckpointFileManager uses
[https://github.com/apache/hadoop/blob/73746c5da76d5e39df131534a1ec35dfc5d2529b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFileSystem.java]
which allows to avoid checksums when creating files.
Note that the crc is created when the tmp file is created not during rename or
mv.
I will create a PR shortly.
was (Author: skonto):
There is a workaround by setting `--conf
spark.hadoop.spark.sql.streaming.checkpointFileManagerClass=org.apache.spark.sql.execution.streaming.FileSystemBasedCheckpointFileManager`
when using local fs
and modifying the FileSystemBasedCheckpointFileManager to run
`fs.setWriteChecksum(false)` after fs is created.
Reason is the FileContextBasedCheckpointFileManager will use ChecksumFS
([https://github.com/apache/hadoop/blob/73746c5da76d5e39df131534a1ec35dfc5d2529b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFs.java])
under the hoods which will ignore "
CreateOpts.checksumParam(ChecksumOpt.createDisabled())" passed. These settings
will only avoid creating checksums for the checksums themshelves.
FileSystemBasedCheckpointFileManager uses
[https://github.com/apache/hadoop/blob/73746c5da76d5e39df131534a1ec35dfc5d2529b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ChecksumFileSystem.java]
which allows to avoid checksums when creating files.
Note that the crc is created when the tmp file is created not during rename or
mv.
> 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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