[ https://issues.apache.org/jira/browse/HDFS-2476?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Todd Lipcon updated HDFS-2476: ------------------------------ Resolution: Fixed Fix Version/s: 0.24.0 Target Version/s: 0.24.0 Hadoop Flags: Reviewed Status: Resolved (was: Patch Available) > More CPU efficient data structure for > under-replicated/over-replicated/invalidate blocks > ---------------------------------------------------------------------------------------- > > Key: HDFS-2476 > URL: https://issues.apache.org/jira/browse/HDFS-2476 > Project: Hadoop HDFS > Issue Type: Sub-task > Components: name-node > Reporter: Tomasz Nykiel > Assignee: Tomasz Nykiel > Fix For: 0.24.0 > > Attachments: hashStructures.patch, hashStructures.patch-2, > hashStructures.patch-3, hashStructures.patch-4, hashStructures.patch-5, > hashStructures.patch-6, hashStructures.patch-7, hashStructures.patch-8, > hashStructures.patch-9 > > > This patch introduces two hash data structures for storing under-replicated, > over-replicated and invalidated blocks. > 1. LightWeightHashSet > 2. LightWeightLinkedSet > Currently in all these cases we are using java.util.TreeSet which adds > unnecessary overhead. > The main bottlenecks addressed by this patch are: > -cluster instability times, when these queues (especially under-replicated) > tend to grow quite drastically, > -initial cluster startup, when the queues are initialized, after leaving > safemode, > -block reports, > -explicit acks for block addition and deletion > 1. The introduced structures are CPU-optimized. > 2. They shrink and expand according to current capacity. > 3. Add/contains/delete ops are performed in O(1) time (unlike current log n > for TreeSet). > 4. The sets are equipped with fast access methods for polling a number of > elements (get+remove), which are used for handling the queues. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira