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https://issues.apache.org/jira/browse/HBASE-28884?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17885885#comment-17885885
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Wellington Chevreuil commented on HBASE-28884:
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Sure, have opened an addendum PR with comments.
> SFT's BrokenStoreFileCleaner may cause data loss
> ------------------------------------------------
>
> Key: HBASE-28884
> URL: https://issues.apache.org/jira/browse/HBASE-28884
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.6.0, 3.0.0-beta-1, 2.7.0, 2.5.10
> Reporter: Wellington Chevreuil
> Assignee: Wellington Chevreuil
> Priority: Major
> Labels: pull-request-available
> Fix For: 2.7.0, 3.0.0-beta-2
>
>
> When having this BrokenStoreFileCleaner enabled, one of our customers has run
> into a data loss situation, probably due to a race condition between regions
> getting moved out of the regionserver while the BrokenStoreFileCleaner was
> checking this region's files eligibility for deletion. We have seen that the
> file got deleted by the given region server, around the same time the region
> got closed on this region server. I believe a race condition during region
> close is possible here:
> 1) In BrokenStoreFileCleaner, for each region online on the given RS, we get
> the list of files in the store dirs, then iterate through it [1];
> 2) For each file listed, we perform several checks, including this one [2]
> that checks if the file is "active"
> The problem is, if the region for the file we are checking got closed between
> point #1 and #2, by the time we check if the file is active in [2], the store
> may have already been closed as part of the region closure, so this check
> would consider the file as deletable.
> One simple solution is to check if the store's region is still open before
> proceeding with deleting the file.
> [1]
> https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/BrokenStoreFileCleaner.java#L99
> [2]
> https://github.com/apache/hbase/blob/master/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/BrokenStoreFileCleaner.java#L133
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