[ http://issues.apache.org/jira/browse/HADOOP-334?page=comments#action_12447602 ] Sameer Paranjpye commented on HADOOP-334: -----------------------------------------
Yes, a sequence number is more robust in the face of time rollbacks. W.r.t the comment on transaction 'm' and how it affects transaction 'x', if we say that: A transaction in the edits log applies to the namespace iff: a. the sequence number on the transaction is higher than the sequence number of the node that it affects OR b. if the node does not exist in the namespace the sequence number of the transaction is more recent than that of the closest existing ancestor then it should work. > Redesign the dfs namespace datastructures to be copy on write > ------------------------------------------------------------- > > Key: HADOOP-334 > URL: http://issues.apache.org/jira/browse/HADOOP-334 > Project: Hadoop > Issue Type: Improvement > Components: dfs > Affects Versions: 0.4.0 > Reporter: Owen O'Malley > Assigned To: Konstantin Shvachko > > The namespace datastructures should be copy on write so that the namespace > does not need to be completely locked down from user changes while the > checkpoint is being made. -- This message is automatically generated by JIRA. - If you think it was sent incorrectly contact one of the administrators: http://issues.apache.org/jira/secure/Administrators.jspa - For more information on JIRA, see: http://www.atlassian.com/software/jira
