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Hairong Kuang commented on HDFS-512: ------------------------------------ > Why does ReplicaInfo need genStamp field. Don't we always have it in Block? > If we do could you please add a comment clarifying what this field actually > is. Now the key is block id so the returned entry from the map may have a different generation stamp but there is no efficient way to get the key in the map so I add the generation stamp to the value field. > Set block id as the key to Block > -------------------------------- > > Key: HDFS-512 > URL: https://issues.apache.org/jira/browse/HDFS-512 > Project: Hadoop HDFS > Issue Type: Improvement > Affects Versions: 0.21.0 > Reporter: Hairong Kuang > Assignee: Hairong Kuang > Fix For: 0.21.0 > > Attachments: blockKey.patch > > > Currently the key to Block is block id + generation stamp. I would propose to > change it to be only block id. This is based on the following properties of > the dfs cluster: > 1. On each datanode only one replica of block exists. Therefore there is only > one generation of a block. > 2. NameNode has only one entry for a block in its blocks map. > With this change, search for a block/replica's meta information is easier > since most of the time we know a block's id but may not know its generation > stamp. -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.