[jira] [Created] (SPARK-28025) HDFSBackedStateStoreProvider leaks .crc files

["Gerard Maas (JIRA)" <ji...@apache.org>]

Gerard Maas created SPARK-28025:
-----------------------------------

             Summary: HDFSBackedStateStoreProvider leaks .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


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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