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Konstantin Shvachko commented on HDFS-8999: ------------------------------------------- > Let's test with the last block to see if it already solves the problem. I > hesitates to be so aggressive. Did you test without this patch? How? May be the problem is already solved just with HDFS-1172, as I argued above. > Namenode need not wait for {{blockReceived}} for the last block before > completing a file. > ----------------------------------------------------------------------------------------- > > Key: HDFS-8999 > URL: https://issues.apache.org/jira/browse/HDFS-8999 > Project: Hadoop HDFS > Issue Type: Bug > Components: namenode > Reporter: Jitendra Nath Pandey > Assignee: Tsz Wo Nicholas Sze > Attachments: h8999_20151228.patch, h8999_20160106.patch, > h8999_20160106b.patch, h8999_20160106c.patch > > > This comes out of a discussion in HDFS-8763. Pasting [~jingzhao]'s comment > from the jira: > {quote} > ...whether we need to let NameNode wait for all the block_received msgs to > announce the replica is safe. Looking into the code, now we have > # NameNode knows the DataNodes involved when initially setting up the > writing pipeline > # If any DataNode fails during the writing, client bumps the GS and > finally reports all the DataNodes included in the new pipeline to NameNode > through the updatePipeline RPC. > # When the client received the ack for the last packet of the block (and > before the client tries to close the file on NameNode), the replica has been > finalized in all the DataNodes. > Then in this case, when NameNode receives the close request from the client, > the NameNode already knows the latest replicas for the block. Currently the > checkReplication call only counts in all the replicas that NN has already > received the block_received msg, but based on the above #2 and #3, it may be > safe to also count in all the replicas in the > BlockUnderConstructionFeature#replicas? > {quote} -- This message was sent by Atlassian JIRA (v6.3.4#6332)