-Re: Long running Join Query - Reduce task fails due to failing to report status
Why don't you try splitting the big query into smaller ones?
On Fri, Aug 24, 2012 at 10:20 AM, Tim Havens <[EMAIL PROTECTED]> wrote:
> Just curious if you've tried using Hive's explain method to see what IT
> thinks of your query.
> On Fri, Aug 24, 2012 at 9:36 AM, Himanish Kushary <[EMAIL PROTECTED]>wrote:
>> We have a complex query that involves several left outer joins resulting
>> in 8 M/R jobs in Hive.During execution of one of the stages ( after three
>> M/R has run) the M/R job fails due to few Reduce tasks failing due to
>> Most of the reduce tasks go through fine ( within 3 mins) but the last
>> one gets stuck for a long time (> 1 hour) and finally after several
>> attempts gets killed due to "failed to report status for 600 seconds.
>> What may be causing this issue ? Would hive.script.auto.progress help in
>> this case ? As we are not able to get much information from the log files
>> how may we approach resolving this ? Will tweaking of any specific M/R
>> parameters help ?
>> The task attempt log shows several lines like this before exiting :
>> 2012-08-23 19:17:23,848 INFO ExecReducer: ExecReducer: processing 219000000 rows: used memory = 408582240
>> 2012-08-23 19:17:30,189 INFO ExecReducer: ExecReducer: processing 220000000 rows: used memory = 346110400
>> 2012-08-23 19:17:37,510 INFO ExecReducer: ExecReducer: processing 221000000 rows: used memory = 583913576
>> 2012-08-23 19:17:44,829 INFO ExecReducer: ExecReducer: processing 222000000 rows: used memory = 513071504
>> 2012-08-23 19:17:47,923 INFO org.apache.hadoop.mapred.FileInputFormat: Total input paths to process : 1
>> Here are the reduce task counters:
>> *Map-Reduce Framework* Combine input records0 Combine output records0Reduce input groups
>> 222,480,335 Reduce shuffle bytes7,726,141,897 Reduce input records
>> 222,480,335 Reduce output records0 Spilled Records355,827,191 CPU time
>> spent (ms)2,152,160 Physical memory (bytes) snapshot1,182,490,624Virtual memory (bytes) snapshot
>> 1,694,531,584 Total committed heap usage (bytes)990,052,352
>> The tasktracker log gives a thread dump at that time but no exception.
>> *2012-08-23 20:05:49,319 INFO org.apache.hadoop.mapred.TaskTracker:
>> Process Thread Dump: lost task*
>> *69 active threads*
>> Thanks & Regards
> "The whole world is you. Yet you keep thinking there is something else." -
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> Tim R. Havens
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