[
https://issues.apache.org/jira/browse/HDFS-4213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13502468#comment-13502468
]
Todd Lipcon commented on HDFS-4213:
-----------------------------------
This patch seems to only add the flag to hsync()'s parameters. It seems like a
valid use case to allow an hflush() which updates the NN's metadata without
actually causing an fsync on the datanodes.
Another suggested improvement for the API: can we take an EnumSet of flags,
instead of a boolean? Then if we have other flags we want to add for
hsync/hflush, it will be easier to extend the API for them in the future
without adding a combinatorial number of functions. (eg I could see a flag like
FSYNC_AT_LEAST_ONE_DN being useful)
> When the client calls hsync(), allows the client to update the file length in
> the NameNode
> ------------------------------------------------------------------------------------------
>
> Key: HDFS-4213
> URL: https://issues.apache.org/jira/browse/HDFS-4213
> Project: Hadoop HDFS
> Issue Type: New Feature
> Affects Versions: 3.0.0
> Reporter: Jing Zhao
> Assignee: Jing Zhao
> Attachments: HDFS-4213.001.patch, HDFS-4213.002.patch,
> HDFS-4213.003.patch
>
>
> As per discussion in HDFS-3960 and HDFS-2802, when clients that need strong
> consistency update the file length at the NameNode, a special sync is
> required for getting the length of the being written files when snapshots are
> taken for these files. This jira implements this sync-with-updating-length by
> 1) calling ClientProtocol#fsync(), and 2) adding a new field to
> ClientProtocol#fsync() to indicate the length information.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
