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ASF GitHub Bot commented on HDFS-16999: --------------------------------------- Hexiaoqiao commented on PR #5622: URL: https://github.com/apache/hadoop/pull/5622#issuecomment-1535670070 @zhangshuyan0 Thanks for your proposal and try to fix this issue. Just glance the PR, it propose to switch `processFirstBlockReport` to `processReport` when restart DataNode only, right? I am concerned the performance if we do that. a. Is it possible to improve `processFirstBlockReport` to solve this issue? b. Will it affect the process logic or performance when add one new DataNode to cluster? Thanks again. > Fix wrong use of processFirstBlockReport() > ------------------------------------------ > > Key: HDFS-16999 > URL: https://issues.apache.org/jira/browse/HDFS-16999 > Project: Hadoop HDFS > Issue Type: Bug > Reporter: Shuyan Zhang > Assignee: Shuyan Zhang > Priority: Major > Labels: pull-request-available > > `processFirstBlockReport()` is used to process first block report from > datanode. It does not calculating `toRemove` list because it believes that > there is no metadata about the datanode in the namenode. However, If a > datanode is re registered after restarting, its `blockReportCount` will be > updated to 0. That is to say, the first block report after a datanode > restarts will be processed by `processFirstBlockReport()`. This is > unreasonable because the metadata of the datanode already exists in namenode > at this time, and if redundant replica metadata is not removed in time, the > blocks with insufficient replicas cannot be reconstruct in time, which > increases the risk of missing block. In summary, `processFirstBlockReport()` > should only be used when the namenode restarts, not when the datanode > restarts. -- This message was sent by Atlassian Jira (v8.20.10#820010) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org