[ https://issues.apache.org/jira/browse/HDFS-4103?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tsz Wo (Nicholas), SZE updated HDFS-4103: ----------------------------------------- Attachment: h4103_20121218.patch h4103_20121218.patch: removes replaceChild method; always uses replaceSelf. > Support O(1) snapshot creation > ------------------------------ > > Key: HDFS-4103 > URL: https://issues.apache.org/jira/browse/HDFS-4103 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: namenode > Affects Versions: Snapshot (HDFS-2802) > Reporter: Tsz Wo (Nicholas), SZE > Assignee: Tsz Wo (Nicholas), SZE > Attachments: h4103_20121129.patch, h4103_20121202b.patch, > h4103_20121202.patch, h4103_20121209b.patch, h4103_20121209.patch, > h4103_20121210b.patch, h4103_20121210.patch, h4103_20121211.patch, > h4103_20121212b.patch, h4103_20121212.patch, h4103_20121213.patch, > h4103_20121215b.patch, h4103_20121215.patch, h4103_20121216.patch, > h4103_20121217b.patch, h4103_20121217.patch, h4103_20121218.patch > > > In our first snapshot implementation, snapshot creation runs in O(N) and > occupies O(N) memory space, where N = # files + # directories + # symlinks in > the snapshot. The advantages of the implementation are that there is no > additional cost for the modifications after snapshots are created, and it > leads to a simple implementation. > In this JIRA, we optimize snapshot creation to O(1) although it introduces > additional cost in the modifications after snapshots are created. Note that > the INode is given as an assumption, otherwise, there is a non-constant cost > to find the INode. -- 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