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https://issues.apache.org/jira/browse/HBASE-16578?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jingcheng Du updated HBASE-16578:
---------------------------------
    Description: 
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}}.

  was:
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 compaction. Some older cells might be chosen during 
the 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}}.


> 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: 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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