[
https://issues.apache.org/jira/browse/HADOOP-2330?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12623061#action_12623061
]
Hairong Kuang commented on HADOOP-2330:
---------------------------------------
Dhruba, this patch makes EditLogOutputStream to have two file handlers to the
edit log: a random access file handler and a file output stream. I think we
only need the file output stream handler. It would make the code more readable.
> Preallocate transaction log to improve namenode transaction logging
> performance
> -------------------------------------------------------------------------------
>
> Key: HADOOP-2330
> URL: https://issues.apache.org/jira/browse/HADOOP-2330
> Project: Hadoop Core
> Issue Type: Improvement
> Components: dfs
> Reporter: dhruba borthakur
> Assignee: dhruba borthakur
> Attachments: preallocateTransactionLog.patch,
> preallocateTransactionLog.patch, preallocateTransactionLog2.patch
>
>
> In the current implementation, the transaction log is opened in "append" mode
> and every new transaction is written to the end of the log. This means that
> new blocks get allocated to the edits file frequently.
> It is worth measuring the performance improvement when big chunks of the
> transaction log are allocated up front. Adding new transactions do not cause
> frequent block allocations for the edits log.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
