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Vinay commented on HDFS-5014: ----------------------------- {quote}However, I think updateActorStatesFromHeartbeat needs to hold the write lock for the entire method. {quote} Actually if we try holding writeLock() throughout method, then that will be same as adding method level synchronization. where we would get the same issue as this jira. {quote}we could get some unfortunate interleavings of state in bpServiceToActive, bposThinksActive, lastActiveClaimTxId, and isMoreRecentClaim.{quote} I dint understand how we could get 'some unfortunate interleavings'. Can you please explain.. I thought since we are reading under lock, we would get correct state always. Regarding findbugs, I will try to fix it. > BPOfferService#processCommandFromActor() synchronization on namenode RPC call > delays IBR to Active NN, if Stanby NN is unstable > ------------------------------------------------------------------------------------------------------------------------------- > > Key: HDFS-5014 > URL: https://issues.apache.org/jira/browse/HDFS-5014 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode, ha > Affects Versions: 3.0.0, 2.0.4-alpha > Reporter: Vinay > Assignee: Vinay > Attachments: HDFS-5014.patch, HDFS-5014.patch, HDFS-5014.patch > > > In one of our cluster, following has happened which failed HDFS write. > 1. Standby NN was unstable and continously restarting due to some errors. But > Active NN was stable. > 2. MR Job was writing files. > 3. At some point SNN went down again while datanode processing the REGISTER > command for SNN. > 4. Datanodes started retrying to connect to SNN to register at the following > code in BPServiceActor#retrieveNamespaceInfo() which will be called under > synchronization. > {code} try { > nsInfo = bpNamenode.versionRequest(); > LOG.debug(this + " received versionRequest response: " + nsInfo); > break;{code} > Unfortunately in all datanodes at same point this happened. > 5. For next 7-8 min standby was down, and no blocks were reported to active > NN at this point and writes have failed. > So culprit is {{BPOfferService#processCommandFromActor()}} is completely > synchronized which is not required. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira