[ https://issues.apache.org/jira/browse/HDFS-14809?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Wei-Chiu Chuang reassigned HDFS-14809: -------------------------------------- Assignee: KenCao (was: kencao) > Reduce BlockReaderLocal RPC calls > --------------------------------- > > Key: HDFS-14809 > URL: https://issues.apache.org/jira/browse/HDFS-14809 > Project: Hadoop HDFS > Issue Type: New Feature > Affects Versions: 2.6.0 > Reporter: KenCao > Assignee: KenCao > Priority: Major > Attachments: HADOOP-14809 > > > as we known, the hdfs client java lib uses BlockReaderLocal for short circuit > read by default, which allocate shared memory first, and make a slot within > it. After all these steps, it will request the fds from the DataNode. > However, the slot and shared memory sturcture is only used by DataNode when > uncaching replicas, the client process can work well just with the fds asked > later and it is nearly impossible to cache replicas in product environment. > The api to release fds is called by client only with the slot given, the fds > is close in the client process finally. > so i think we can make a new BlockReader implementation which just requests > the fds, and it will reduce the rpc calls from 3(allocate shm, request fds, > release fds) to 1(request fds). -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org