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https://issues.apache.org/jira/browse/BOOKKEEPER-572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13823711#comment-13823711
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Ivan Kelly commented on BOOKKEEPER-572:
---------------------------------------

Ya, I'll close for now. I think it could still have value, once the rest of the 
storage changes are in, but if that is the case, we can reopen.


> Make the journal a write ahead log
> ----------------------------------
>
>                 Key: BOOKKEEPER-572
>                 URL: https://issues.apache.org/jira/browse/BOOKKEEPER-572
>             Project: Bookkeeper
>          Issue Type: Bug
>            Reporter: Ivan Kelly
>            Assignee: Ivan Kelly
>         Attachments: 
> 0001-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> 0001-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> 0001-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> 0001-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> 0003-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> 0003-BOOKKEEPER-572-Write-to-the-journal-before-writing-t.patch, 
> BookieServer-2013-02-22.snapshot
>
>
> A bookie adds to the LedgerStorage before writing to the journal. This is the 
> fundamental problem behind BOOKKEEPER-447 and blocks a nice solution to 
> BOOKKEEPER-530. By writing to the memory state before the journal, we exposed 
> ourselves to bugs if the bookie crashed before we wrote to the journal. The 
> entry may exist in index, but not in the entrylog, a situation which cannot 
> be distinguished from an I/O error. The comments on BOOKKEEPER-447 goes into 
> more details. 



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