[
https://issues.apache.org/jira/browse/HUDI-2925?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17453050#comment-17453050
]
sivabalan narayanan commented on HUDI-2925:
-------------------------------------------
I have some clarifications wrt the issue being very specific to metadata table.
The files to be cleaned up as part of a clean action is determined during
planning phase and is serialized in the requested instant. So, in above
scenario, if 102.clean is not complete when 104.clean is requested, during
planning phase of 104, we would still add files pertaining to 90.commit and not
91.commit to 104.clean.requested. So, we would still encounter the same problem
during action phase. Can you help throw some light here please.
> 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.
>
--
This message was sent by Atlassian Jira
(v8.20.1#820001)
