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https://issues.apache.org/jira/browse/FLINK-30461?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17649696#comment-17649696
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Rui Fan commented on FLINK-30461:
---------------------------------
Hi [~pnowojski] , could you please help take a look in your free time? thanks :)
And I have a POC commit to fix this bug.
[https://github.com/1996fanrui/flink/commit/86a456b2bbdad6c032bf8e0bff71c4824abb3ce1]
BTW, FLINK-28984 is also a bug caused some checkpoint files remain forever. I
have fixed these 2 bugs in my test job, no files remain with these fixes.
> Some rocksdb sst files will remain forever
> ------------------------------------------
>
> Key: FLINK-30461
> URL: https://issues.apache.org/jira/browse/FLINK-30461
> Project: Flink
> Issue Type: Bug
> Components: Runtime / Checkpointing
> Affects Versions: 1.16.0, 1.17.0, 1.15.3
> Reporter: Rui Fan
> Priority: Major
> Attachments: image-2022-12-20-18-45-32-948.png,
> image-2022-12-20-18-47-42-385.png
>
>
> In rocksdb incremental checkpoint mode, during file upload, if some files
> have been uploaded and some files have not been uploaded, the checkpoint
> timeout is canceled at this time, and the uploaded files will remain.
>
> h2. Impact:
> The shared directory of a flink job has more than 1 million files. It
> exceeded the hdfs upper limit, causing new files not to be written.
> However only 50k files are available, the other 950k files should be cleaned
> up.
> !https://user-images.githubusercontent.com/38427477/207588272-dda7ba69-c84c-4372-aeb4-c54657b9b956.png|width=1962,height=364!
> h2. Root cause:
> If an exception is thrown during the checkpoint async phase, flink will clean
> up metaStateHandle, miscFiles and sstFiles.
> However, when all sst files are uploaded, they are added together to
> sstFiles. If some sst files have been uploaded and some sst files are still
> being uploaded, and the checkpoint timeout is canceled at this time, all sst
> files will not be added to sstFiles. The uploaded sst will remain on hdfs.
> [code
> link|https://github.com/apache/flink/blob/49146cdec41467445de5fc81f100585142728bdf/flink-state-backends/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/snapshot/RocksIncrementalSnapshotStrategy.java#L328]
> h2. Solution:
> Using the CloseableRegistry as the tmpResourcesRegistry. If the async phase
> is failed, the tmpResourcesRegistry will cleanup these temporary resources.
>
> POC code:
> https://github.com/1996fanrui/flink/commit/86a456b2bbdad6c032bf8e0bff71c4824abb3ce1
>
>
> !image-2022-12-20-18-45-32-948.png|width=1114,height=442!
> !image-2022-12-20-18-47-42-385.png|width=1332,height=552!
>
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