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https://issues.apache.org/jira/browse/HUDI-2925?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17453249#comment-17453249
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Prashant Wason commented on HUDI-2925:
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In the latest 0.10 release I see that the cleaner plan is created before the
previous unfinished clean are run. This is different from older versions where
the new cleaner plan will be created after the previous unfinished cleans are
completed.
So your understanding is right. The fix involves 2 parts:
1. Refreshing fsview during CleanActionExecutor forEach where the previous
cleans are completed
2. Creating the new clean plan post completion of unfinished cleans.
> Cleaner may attempt to delete the same file twice when metadata table is
> enabled
> --------------------------------------------------------------------------------
>
> Key: HUDI-2925
> URL: https://issues.apache.org/jira/browse/HUDI-2925
> Project: Apache Hudi
> Issue Type: Bug
> Reporter: Prashant Wason
> Assignee: Prashant Wason
> Priority: Blocker
> Fix For: 0.10.0
>
>
> This issue happens only when TimelineServer is disabled (reason in next
> comment). Our pipelines execute a write (insert or upsert) along with an
> asynchronous clean. Metadata table is enabled.
>
> Assume the timelines are as follows:
> Dataset: 100.commit 101.commit 102.clean.inflight
> Metadata: 100.deltacomit
> (this happened as the pipeline failed due to non-HUDI issues which executing
> 101 and 102)
>
> In the next run of the pipeline some more data is available so a commit will
> take place (103.commit.requested). Along with it, an asynchronous clean
> starts (104.clean.requested). The [BaseCleanActionExecutor detected
> previously unfinished
> clean|https://github.com/apache/hudi/blob/master/hudi-client/hudi-client-common/src/main/java/org/apache/hudi/table/action/clean/CleanActionExecutor.java#L231]
> (102.clean.inflight) and attempts to do it first. So the order of cleans
> will be 102.clean followed by 104.clean.
>
> 102.clean => Suppose this deletes files from 90.commit
> 104.clean => This should delete files from 91.commit
>
> The issue is that while executing 104.clean, the filesystemview is still the
> one which was used during 102.clean (i.e. post clean the file system view is
> not synced). When metadata table is enabled, HoodieMetadataFileSystemView is
> used which has the metadata reader inside it. This metadata reader opens the
> metadata table at a particular time instant (will be 101.commit as that was
> the last completed action). Even after 102.clean is completed, the
> HoodieMetadataFileSystemView is still using the cached metadata reader.
> Hence, the reader still returns files from 90.commit which have already been
> deleted by 102.clean.
>
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