[ https://issues.apache.org/jira/browse/HDFS-8988?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Yi Liu updated HDFS-8988: ------------------------- Attachment: HDFS-8988.002.patch Rebase the patch. > Use LightWeightHashSet instead of LightWeightLinkedSet in > BlockManager#excessReplicateMap > ----------------------------------------------------------------------------------------- > > Key: HDFS-8988 > URL: https://issues.apache.org/jira/browse/HDFS-8988 > Project: Hadoop HDFS > Issue Type: Improvement > Reporter: Yi Liu > Assignee: Yi Liu > Attachments: HDFS-8988.001.patch, HDFS-8988.002.patch > > > {code} > public final Map<String, LightWeightLinkedSet<Block>> excessReplicateMap = > new HashMap<>(); > {code} > {{LightWeightLinkedSet}} extends {{LightWeightHashSet}} and in addition it > stores elements in double linked list to ensure ordered traversal. So it > requires more memory for each entry (2 references = 8 + 8 bytes = 16 bytes, > assume 64-bits system/JVM). > I have traversed the source code, and we don't need ordered traversal for > excess replicated blocks, so could use {{LightWeightHashSet}} to save memory. -- This message was sent by Atlassian JIRA (v6.3.4#6332)