[jira] [Comment Edited] (HBASE-20611) UnsupportedOperationException may thrown when calling getCallQueueInfo()

["Chia-Ping Tsai (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-20611?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16504162#comment-16504162 ] 

Chia-Ping Tsai edited comment on HBASE-20611 at 6/7/18 2:24 AM:
----------------------------------------------------------------

{code:java}
+      if (lastModifyCount != modifyCount) { // structure has been modified since #iterator called
+        throw new ConcurrentModificationException();
+      }{code}
The queue is changed frequently so the error may happen frequently also. Could we do the snapshot of objects? If it is impossible to do the snapshot, we have to handle the error on RSDumpServlet#dumpCallQueues. Otherwise, user will be scared by our web UI.
{code:java}
+  @Override
+  public Iterator<CallRunner> iterator(){
+    return new AdaptiveLifoCoDelCallQueue.Itr();
+  }
+
+  private final class Itr implements Iterator<CallRunner> {
+    private int index = 0;
+    private Object[] crArray = AdaptiveLifoCoDelCallQueue.this.queue.toArray();
+    int size = crArray.length;
+    public boolean hasNext() {
+      return index < size;
+    }
+
+    @SuppressWarnings("unchecked")
+    public CallRunner next() {
+      if (index < size) {
+        return (CallRunner) crArray[index++];
+      }
+      throw new NoSuchElementException();
+    }
+  }{code}
BTW, if the Itr is not fat, we can use anonymous class instead. Also, please make the fields final as much as possible.

 


was (Author: chia7712):
{code:java}
+      if (lastModifyCount != modifyCount) { // structure has been modified since #iterator called
+        throw new ConcurrentModificationException();
+      }{code}
The queue is changed frequently so the error may happen frequently also. Could we do the snapshot of objects? If it is impossible to do the snapshot, we have to handle the error on RSDumpServlet#dumpCallQueues. Otherwise, user will be scared by our web UI.
{code:java}
+  @Override
+  public Iterator<CallRunner> iterator(){
+    return new AdaptiveLifoCoDelCallQueue.Itr();
+  }
+
+  private final class Itr implements Iterator<CallRunner> {
+    private int index = 0;
+    private Object[] crArray = AdaptiveLifoCoDelCallQueue.this.queue.toArray();
+    int size = crArray.length;
+    public boolean hasNext() {
+      return index < size;
+    }
+
+    @SuppressWarnings("unchecked")
+    public CallRunner next() {
+      if (index < size) {
+        return (CallRunner) crArray[index++];
+      }
+      throw new NoSuchElementException();
+    }
+  }{code}
BTW, if the Itr is not fat, we can use inner class instead. Also, please make the fields final as much as possible.

 

> UnsupportedOperationException may thrown when calling getCallQueueInfo()
> ------------------------------------------------------------------------
>
>                 Key: HBASE-20611
>                 URL: https://issues.apache.org/jira/browse/HBASE-20611
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 2.0.0
>            Reporter: Allan Yang
>            Assignee: Xu Cang
>            Priority: Major
>         Attachments: HBASE-20611.master.002.patch, HBASE-20611.master.003.patch, HBASE-20611.master.004.patch, HBASE-20611.master.005.patch, HBASE-20611.master.006.patch, HBASE-20611.master.007.patch
>
>
> HBASE-16290 added a new feature to dump queue info,  the method getCallQueueInfo() need to iterate the queue to get the elements in the queue.  But, except the Java's LinkedBlockingQueue, the other queue implementations like BoundedPriorityBlockingQueue and AdaptiveLifoCoDelCallQueue don't implement the method iterator(). If those queues are used, a UnsupportedOperationException  will be thrown.
> This can be easily be reproduced by the UT testCallQueueInfo while adding a conf: conf.set("hbase.ipc.server.callqueue.type", "deadline")
> {code}
> java.lang.UnsupportedOperationException
> 	at org.apache.hadoop.hbase.util.BoundedPriorityBlockingQueue.iterator(BoundedPriorityBlockingQueue.java:285)
> 	at org.apache.hadoop.hbase.ipc.RpcExecutor.getCallQueueCountsSummary(RpcExecutor.java:166)
> 	at org.apache.hadoop.hbase.ipc.SimpleRpcScheduler.getCallQueueInfo(SimpleRpcScheduler.java:241)
> 	at org.apache.hadoop.hbase.ipc.TestSimpleRpcScheduler.testCallQueueInfo(TestSimpleRpcScheduler.java:164)
> {code}



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