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https://issues.apache.org/jira/browse/HBASE-16578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15571183#comment-15571183
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Jingcheng Du commented on HBASE-16578:
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The failures of the these unit tests are caused by the OOM, should not be
related with this patch.
I will commit this after [~mbertozzi] reviews or tomorrow. Thanks.
> Mob data loss after mob compaction and normal compcation
> --------------------------------------------------------
>
> Key: HBASE-16578
> URL: https://issues.apache.org/jira/browse/HBASE-16578
> Project: HBase
> Issue Type: Bug
> Components: mob
> Affects Versions: 2.0.0
> Reporter: huaxiang sun
> Assignee: Jingcheng Du
> Attachments: HBASE-16578-V2.patch, HBASE-16578.patch,
> TestMobCompaction.java, TestMobCompaction.java
>
>
> StoreFileScanners on MOB cells rely on the scannerOrder to find the latest
> cells after mob compaction. The value of scannerOrder is assigned by the
> order of maxSeqId of StoreFile, and this maxSeqId is valued only after the
> reader of the StoreFile is created.
> In {{Compactor.compact}}, the compacted store files are cloned and their
> readers are not created. And in {{StoreFileScanner.getScannersForStoreFiles}}
> the StoreFiles are sorted before the readers are created and at that time the
> maxSeqId for each file is -1 (the default value). This will lead to a chaos
> in scanners in the following normal compaction. Some older cells might be
> chosen during the normal compaction.
> We need to create readers either before the sorting in the method
> {{StoreFileScanner.getScannersForStoreFiles}}, or create readers just after
> the store files are cloned in {{Compactor.compact}}.
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