[jira] [Commented] (MAPREDUCE-4227) TimeWindow statistics are not updated for TaskTrackers which have been restarted.

["Ravi Prakash (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-4227?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13268715#comment-13268715 ] 

Ravi Prakash commented on MAPREDUCE-4227:
-----------------------------------------

I'd been banging my head on this bug for weeks and then Koji swept in like an angel that he is, and rescued me.

Courtesy Koji!
{quote}
src/mapred/org/apache/hadoop/mapred/StatisticsCollector.java
{noformat}
276     synchronized void update() {
277       updates++;
278       if (updates == updatesPerBucket) {
279         for(TimeStat stat : statToCollect.values()) {
280           stat.addBucket();
281         }
282         updates = 0;
283         buckets++;
284         if (buckets > collectBuckets) {
285           for (TimeStat stat : statToCollect.values()) {
286             stat.removeBucket();
287           }
288           buckets--;
289         }
290       }
291     }
292   }
{noformat}
'bucket' keeps track of how many buckets ALL the TimeStat has for that Range (Hourly,Daily) so after 1 hour, buckets == collectBuckets and each time it adds, it takes out 1.
i believe the incorrect assumption they are making here is ALL the TimeStat would have same number of buckets
{quote}

One of these days I'll start a Koji fan club! Please consider joining.
                
> TimeWindow statistics are not updated for TaskTrackers which have been restarted.
> ---------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-4227
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-4227
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>    Affects Versions: 0.20.205.0
>            Reporter: Ravi Prakash
>            Assignee: Ravi Prakash
>
> Whenever a TaskTracker is restarted after the JobTracker has been running for a while (an hour / day maybe), the TimeWindow statistics on the JobTracker Active nodes page are stuck at 0.

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