hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "huaxiang sun (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-16578) Mob data loss after mob compaction and normal compcation
Date Fri, 14 Oct 2016 01:20:20 GMT

    [ https://issues.apache.org/jira/browse/HBASE-16578?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15573760#comment-15573760
] 

huaxiang sun commented on HBASE-16578:
--------------------------------------

I reviewed  Jingcheng's fix. I have one case which I think it will not work.

1. put mob cell r1, flush, it will create ref1 and mobFile1.
2. put mob cell r2, flush, it will create ref2 and mobFile2.
3. put normal cell r3, flush, it will create hfile3.
4. minor or major compact, ref1, ref2, hfile3, it creates hfile4.
5. mob compact, it will create mobfile3 and bulkload ref3.
6. compact hfile4 and ref3, then again ref cells in hfile4 will win since hfile4 got a bigger
maxSeqId.

No?

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}}.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message