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Posted to user@hive.apache.org by Marc Limotte <ms...@gmail.com> on 2013/01/31 00:16:02 UTC
delay before query starts processing
Hi,
I'm running in Amazon on an EMR cluster with hive 0.8.1. We have a lot of
other Hadoop jobs, but only started experimenting with Hive recently.
I've been seeing a long pause after submitting a hive query and the
actually start of the hadoop job... 10 minutes or more in some cases. I'm
wondering what's happening during this time. Either a high level answer,
or maybe there is some logging I can turn on?
Here's some more detail. I submit the query on the master using the hive
cli, and start to see some output right away...
Total MapReduce jobs = 2
Launching Job 1 out of 2
Number of reduce tasks not specified. Estimated from input data size: 1
In order to change the average load for a reducer (in bytes):
set hive.exec.reducers.bytes.per.reducer=<number>
In order to limit the maximum number of reducers:
set hive.exec.reducers.max=<number>
In order to set a constant number of reducers:
set mapred.reduce.tasks=<number>
*[then a long delay here: 10 minutes or more... no activity in the hadoop
job tracker ui] *
… and then it continues normally ...
Starting Job = job_201301160029_0082, Tracking URL =
http://ip-xxxxxxxx.ec2.internal:9100/jobdetails.jsp?jobid=job_201301160029_0082
Kill Command = /home/hadoop/bin/hadoop job
-Dmapred.job.tracker=xxxxxx:9001 -kill job_201301160029_0082
Hadoop job information for Stage-1: number of mappers: 2; number of
reducers: 1
2013-01-30 20:45:30,526 Stage-1 map = 0%, reduce = 0%
…
This query is processing in the neighborhood of 500GB of data from S3. A
couple of possibilities I thought of… perhaps someone can confirm or deny:
a) Is the data copied from S3 to HDFS during this time?
b) I have a fairly large set of libs in HIVE_AUX_JAR_PATH (around ~175
MB)-- does it have to copy these around to the tasks at this time?
Any insights appreciated.
Marc
Re: delay before query starts processing
Posted by Ariel Marcus <ar...@openbi.com>.
>From the archives:
http://mail-archives.apache.org/mod_mbox/hive-user/201110.mbox/%3CCAC9SPjuQtxOK1KtEmReD6OanNTgNM_uLkGQD+=n7KRcJcaLmGw@mail.gmail.com%3E
TL;DR set hive.optimize.s3.query=true;
---------------------------------
Ariel Marcus, Consultant
www.openbi.com | ariel.marcus@openbi.com
150 N Michigan Avenue, Suite 2800, Chicago, IL 60601
Cell: 314-827-4356
On Wed, Jan 30, 2013 at 6:16 PM, Marc Limotte <ms...@gmail.com> wrote:
> Hi,
>
> I'm running in Amazon on an EMR cluster with hive 0.8.1. We have a lot of
> other Hadoop jobs, but only started experimenting with Hive recently.
>
> I've been seeing a long pause after submitting a hive query and the
> actually start of the hadoop job... 10 minutes or more in some cases. I'm
> wondering what's happening during this time. Either a high level answer,
> or maybe there is some logging I can turn on?
>
> Here's some more detail. I submit the query on the master using the hive
> cli, and start to see some output right away...
>
> Total MapReduce jobs = 2
> Launching Job 1 out of 2
> Number of reduce tasks not specified. Estimated from input data size: 1
> In order to change the average load for a reducer (in bytes):
> set hive.exec.reducers.bytes.per.reducer=<number>
> In order to limit the maximum number of reducers:
> set hive.exec.reducers.max=<number>
> In order to set a constant number of reducers:
> set mapred.reduce.tasks=<number>
>
>
> *[then a long delay here: 10 minutes or more... no activity in the hadoop
> job tracker ui] *
>
>
> … and then it continues normally ...
> Starting Job = job_201301160029_0082, Tracking URL =
> http://ip-xxxxxxxx.ec2.internal:9100/jobdetails.jsp?jobid=job_201301160029_0082
> Kill Command = /home/hadoop/bin/hadoop job
> -Dmapred.job.tracker=xxxxxx:9001 -kill job_201301160029_0082
> Hadoop job information for Stage-1: number of mappers: 2; number of
> reducers: 1
> 2013-01-30 20:45:30,526 Stage-1 map = 0%, reduce = 0%
> …
>
> This query is processing in the neighborhood of 500GB of data from S3. A
> couple of possibilities I thought of… perhaps someone can confirm or deny:
> a) Is the data copied from S3 to HDFS during this time?
> b) I have a fairly large set of libs in HIVE_AUX_JAR_PATH (around ~175
> MB)-- does it have to copy these around to the tasks at this time?
>
> Any insights appreciated.
>
> Marc
>
>
>
>
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------------------------------
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recipient named above. It may contain confidential, proprietary, or legally
privileged information. If you are not the intended recipient, you are
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in error, please contact the sender by reply e-mail and delete the original
transmission and all copies from your system.
Re: delay before query starts processing
Posted by Marc Limotte <ms...@gmail.com>.
Ariel,
set hive.optimize.s3.query=true seems to help. But I'm surprised, because
the information I can find online about that config suggests that it is
related to tables with a large number of partitions. I have a lot of files,
but only one partition. But it seems to help anyway.
Abdelrahman,
Thanks for the logging tip. I do want to know what it is doing, so this
should be helpful.
Marc
On Wed, Jan 30, 2013 at 3:23 PM, Abdelrahman Shettia <
ashettia@hortonworks.com> wrote:
> Hi Marc,
>
> You can try running the hive client with debug mode on and see what is
> trying to do on the JT level.
> hive -hiveconf hive.root.logger=ALL,console -e " DDL;"
> hive -hiveconf hive.root.logger=ALL,console -f ddl.sql ;
>
> Hope this helps .
>
> Thanks
> -Abdelrahman
>
>
> On Wed, Jan 30, 2013 at 3:16 PM, Marc Limotte <ms...@gmail.com> wrote:
>
>> Hi,
>>
>> I'm running in Amazon on an EMR cluster with hive 0.8.1. We have a lot
>> of other Hadoop jobs, but only started experimenting with Hive recently.
>>
>> I've been seeing a long pause after submitting a hive query and the
>> actually start of the hadoop job... 10 minutes or more in some cases. I'm
>> wondering what's happening during this time. Either a high level answer,
>> or maybe there is some logging I can turn on?
>>
>> Here's some more detail. I submit the query on the master using the hive
>> cli, and start to see some output right away...
>>
>> Total MapReduce jobs = 2
>> Launching Job 1 out of 2
>> Number of reduce tasks not specified. Estimated from input data size: 1
>> In order to change the average load for a reducer (in bytes):
>> set hive.exec.reducers.bytes.per.reducer=<number>
>> In order to limit the maximum number of reducers:
>> set hive.exec.reducers.max=<number>
>> In order to set a constant number of reducers:
>> set mapred.reduce.tasks=<number>
>>
>>
>> *[then a long delay here: 10 minutes or more... no activity in the
>> hadoop job tracker ui] *
>>
>>
>> … and then it continues normally ...
>> Starting Job = job_201301160029_0082, Tracking URL =
>> http://ip-xxxxxxxx.ec2.internal:9100/jobdetails.jsp?jobid=job_201301160029_0082
>> Kill Command = /home/hadoop/bin/hadoop job
>> -Dmapred.job.tracker=xxxxxx:9001 -kill job_201301160029_0082
>> Hadoop job information for Stage-1: number of mappers: 2; number of
>> reducers: 1
>> 2013-01-30 20:45:30,526 Stage-1 map = 0%, reduce = 0%
>> …
>>
>> This query is processing in the neighborhood of 500GB of data from S3. A
>> couple of possibilities I thought of… perhaps someone can confirm or deny:
>> a) Is the data copied from S3 to HDFS during this time?
>> b) I have a fairly large set of libs in HIVE_AUX_JAR_PATH (around ~175
>> MB)-- does it have to copy these around to the tasks at this time?
>>
>> Any insights appreciated.
>>
>> Marc
>>
>>
>>
>>
>
Re: delay before query starts processing
Posted by Abdelrahman Shettia <as...@hortonworks.com>.
Hi Marc,
You can try running the hive client with debug mode on and see what is
trying to do on the JT level.
hive -hiveconf hive.root.logger=ALL,console -e " DDL;"
hive -hiveconf hive.root.logger=ALL,console -f ddl.sql ;
Hope this helps .
Thanks
-Abdelrahman
On Wed, Jan 30, 2013 at 3:16 PM, Marc Limotte <ms...@gmail.com> wrote:
> Hi,
>
> I'm running in Amazon on an EMR cluster with hive 0.8.1. We have a lot of
> other Hadoop jobs, but only started experimenting with Hive recently.
>
> I've been seeing a long pause after submitting a hive query and the
> actually start of the hadoop job... 10 minutes or more in some cases. I'm
> wondering what's happening during this time. Either a high level answer,
> or maybe there is some logging I can turn on?
>
> Here's some more detail. I submit the query on the master using the hive
> cli, and start to see some output right away...
>
> Total MapReduce jobs = 2
> Launching Job 1 out of 2
> Number of reduce tasks not specified. Estimated from input data size: 1
> In order to change the average load for a reducer (in bytes):
> set hive.exec.reducers.bytes.per.reducer=<number>
> In order to limit the maximum number of reducers:
> set hive.exec.reducers.max=<number>
> In order to set a constant number of reducers:
> set mapred.reduce.tasks=<number>
>
>
> *[then a long delay here: 10 minutes or more... no activity in the hadoop
> job tracker ui] *
>
>
> … and then it continues normally ...
> Starting Job = job_201301160029_0082, Tracking URL =
> http://ip-xxxxxxxx.ec2.internal:9100/jobdetails.jsp?jobid=job_201301160029_0082
> Kill Command = /home/hadoop/bin/hadoop job
> -Dmapred.job.tracker=xxxxxx:9001 -kill job_201301160029_0082
> Hadoop job information for Stage-1: number of mappers: 2; number of
> reducers: 1
> 2013-01-30 20:45:30,526 Stage-1 map = 0%, reduce = 0%
> …
>
> This query is processing in the neighborhood of 500GB of data from S3. A
> couple of possibilities I thought of… perhaps someone can confirm or deny:
> a) Is the data copied from S3 to HDFS during this time?
> b) I have a fairly large set of libs in HIVE_AUX_JAR_PATH (around ~175
> MB)-- does it have to copy these around to the tasks at this time?
>
> Any insights appreciated.
>
> Marc
>
>
>
>