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Posted to dev@pig.apache.org by "Olga Natkovich (JIRA)" <ji...@apache.org> on 2008/05/28 02:45:47 UTC
[jira] Created: (PIG-250) Pig is broken with speculative execution
Pig is broken with speculative execution
----------------------------------------
Key: PIG-250
URL: https://issues.apache.org/jira/browse/PIG-250
Project: Pig
Issue Type: Bug
Reporter: Olga Natkovich
If I have speculative execution turned on, the following script fails:
a = load 'studenttab20m' as (name, age, gpa);
b = load 'votertab10k' as (name, age, registration, contributions);
c = filter a by age < '50';
d = filter b by age < '50';
e = cogroup c by (name, age), d by (name, age) parallel 10;
f = foreach e generate flatten(c), flatten(d) parallel 10;
g = group f by registration parallel 10;
h = foreach g generate group, SUM(f.d::contributions) parallel 10;
i = order h by ($1, $0);
store i into 'out';
I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
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[jira] Updated: (PIG-250) Pig is broken with speculative execution
Posted by "Olga Natkovich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Olga Natkovich updated PIG-250:
-------------------------------
Status: Patch Available (was: Open)
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
--
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You can reply to this email to add a comment to the issue online.
[jira] Updated: (PIG-250) Pig is broken with speculative execution
Posted by "Olga Natkovich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Olga Natkovich updated PIG-250:
-------------------------------
Attachment: PIG-250.patch
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
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[jira] Commented: (PIG-250) Pig is broken with speculative
execution
Posted by "Alan Gates (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600837#action_12600837 ]
Alan Gates commented on PIG-250:
--------------------------------
+1
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch, PIG-250_v2.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
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[jira] Commented: (PIG-250) Pig is broken with speculative
execution
Posted by "Arun C Murthy (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600336#action_12600336 ]
Arun C Murthy commented on PIG-250:
-----------------------------------
+1
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Commented: (PIG-250) Pig is broken with speculative
execution
Posted by "Alan Gates (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12600532#action_12600532 ]
Alan Gates commented on PIG-250:
--------------------------------
+1
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Updated: (PIG-250) Pig is broken with speculative execution
Posted by "Olga Natkovich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Olga Natkovich updated PIG-250:
-------------------------------
Resolution: Fixed
Status: Resolved (was: Patch Available)
Latest patch committed. Thanks Arung for figuring out this issue!
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch, PIG-250_v2.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
[jira] Updated: (PIG-250) Pig is broken with speculative execution
Posted by "Olga Natkovich (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/PIG-250?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Olga Natkovich updated PIG-250:
-------------------------------
Attachment: PIG-250_v2.patch
Arun helped to diagnose the problem. It turned out that we were not passing the right directory to the task to write to and as the result all tasks (primary + speculative) were writing to the same place overwriting each others output.
The attached patch fixes the issue and also reverses the prior change of disabling speculative execution. With this changes, by default the speculative execution will be consistent with hadoop default (currently on) and will be controlled by configuration (hadoop-site.xml)
I tested that speculative execution works now and that I can control it from hadoop-site.xml.
Thanks, Arun.
One of the committers - please review.
> Pig is broken with speculative execution
> ----------------------------------------
>
> Key: PIG-250
> URL: https://issues.apache.org/jira/browse/PIG-250
> Project: Pig
> Issue Type: Bug
> Reporter: Olga Natkovich
> Attachments: PIG-250.patch, PIG-250_v2.patch
>
>
> If I have speculative execution turned on, the following script fails:
> a = load 'studenttab20m' as (name, age, gpa);
> b = load 'votertab10k' as (name, age, registration, contributions);
> c = filter a by age < '50';
> d = filter b by age < '50';
> e = cogroup c by (name, age), d by (name, age) parallel 10;
> f = foreach e generate flatten(c), flatten(d) parallel 10;
> g = group f by registration parallel 10;
> h = foreach g generate group, SUM(f.d::contributions) parallel 10;
> i = order h by ($1, $0);
> store i into 'out';
> I traced this to the fact that the first MR job produces one or more empty outputs from the reducer. This happened on the reducers that happened to have second task running.
> I am not sure what the issue is and I am working with hadoop guys to investigate. Until this issue is resolved, I would like to trun speculative execution off.
--
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You can reply to this email to add a comment to the issue online.