[ https://issues.apache.org/jira/browse/HDFS-15115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17014437#comment-17014437 ]
xuzq commented on HDFS-15115: ----------------------------- Thanks [~hexiaoqiao], [~weichiu], [~wzx513], this bug may be still exists after -[HDFS-11827|https://issues.apache.org/jira/browse/HDFS-11827]:(- {code:java} if (LOG.isDebugEnabled()) { detail = builder.toString(); if (badTarget) { builder.setLength(0); } else { if (detail.length() > 1) { // only log if there's more than "[", which is always appended at // the beginning of this method. LOG.debug(detail); } detail = ""; } } {code} > Namenode crash caused by NPE in BlockPlacementPolicyDefault when dynamically > change logger to debug > --------------------------------------------------------------------------------------------------- > > Key: HDFS-15115 > URL: https://issues.apache.org/jira/browse/HDFS-15115 > Project: Hadoop HDFS > Issue Type: Bug > Reporter: wangzhixiang > Priority: Major > Attachments: HDFS-15115.001.patch > > > To get debug info, we dynamically change the logger of > BlockPlacementPolicyDefault to debug when namenode is running. However, the > Namenode crashs. From the log, we find some NPE in > BlockPlacementPolicyDefault.chooseRandom. Because *StringBuilder builder* > will be used 4 times in BlockPlacementPolicyDefault.chooseRandom method. > While the *builder* only initializes in the first time of this method. If we > change the logger of BlockPlacementPolicyDefault to debug after the part, the > *builder* in remaining part is *NULL* and cause *NPE* -- 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