tomscut opened a new pull request #3928: URL: https://github.com/apache/hadoop/pull/3928
JIRA: [HDFS-16438](https://issues.apache.org/jira/browse/HDFS-16438). At the time of decommission, if use `DatanodeAdminBackoffMonitor`, there is a heavy operation: `scanDatanodeStorage`. If the number of blocks on a storage is large(more than 5 million), and GC performance is also poor, it may hold **read lock** for a long time, we should optimize it.  ``` 2021-12-22 07:49:01,279 INFO namenode.FSNamesystem (FSNamesystemLock.java:readUnlock(220)) - FSNamesystem scanDatanodeStorage read lock held for 5491 ms via java.lang.Thread.getStackTrace(Thread.java:1552) org.apache.hadoop.util.StringUtils.getStackTrace(StringUtils.java:1032) org.apache.hadoop.hdfs.server.namenode.FSNamesystemLock.readUnlock(FSNamesystemLock.java:222) org.apache.hadoop.hdfs.server.namenode.FSNamesystem.readUnlock(FSNamesystem.java:1641) org.apache.hadoop.hdfs.server.blockmanagement.DatanodeAdminBackoffMonitor.scanDatanodeStorage(DatanodeAdminBackoffMonitor.java:646) org.apache.hadoop.hdfs.server.blockmanagement.DatanodeAdminBackoffMonitor.checkForCompletedNodes(DatanodeAdminBackoffMonitor.java:417) org.apache.hadoop.hdfs.server.blockmanagement.DatanodeAdminBackoffMonitor.check(DatanodeAdminBackoffMonitor.java:300) org.apache.hadoop.hdfs.server.blockmanagement.DatanodeAdminBackoffMonitor.run(DatanodeAdminBackoffMonitor.java:201) java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308) java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180) java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) java.lang.Thread.run(Thread.java:745) Number of suppressed read-lock reports: 0 Longest read-lock held interval: 5491 ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
