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Posted to common-dev@hadoop.apache.org by "Chris Douglas (JIRA)" <ji...@apache.org> on 2008/08/12 22:59:44 UTC
[jira] Created: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Reduce often attempts in memory merge with no work
--------------------------------------------------
Key: HADOOP-3940
URL: https://issues.apache.org/jira/browse/HADOOP-3940
Project: Hadoop Core
Issue Type: Bug
Components: mapred
Reporter: Chris Douglas
Priority: Minor
ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Attachment: 3940-0.patch
Simplest fix, waiting on numRequiredMapOutputs == 0.
Initializing numRequiredMapOutputs to Integer.MAX_VALUE would require a different check at the end; this should handle both.
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Affects Version/s: 0.18.0
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.0
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Assigned: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Arun C Murthy (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Arun C Murthy reassigned HADOOP-3940:
-------------------------------------
Assignee: Chris Douglas
+1
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Commented: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Hudson (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12624712#action_12624712 ]
Hudson commented on HADOOP-3940:
--------------------------------
Integrated in Hadoop-trunk #581 (See [http://hudson.zones.apache.org/hudson/job/Hadoop-trunk/581/])
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.0
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Fix Version/s: 0.18.1
+1
Merged into 0.18 branch
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.0
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.18.1, 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Resolution: Fixed
Fix Version/s: 0.19.0
Hadoop Flags: [Reviewed]
Status: Resolved (was: Patch Available)
I just committed this
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Commented: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Hadoop QA (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12622256#action_12622256 ]
Hadoop QA commented on HADOOP-3940:
-----------------------------------
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12388084/3940-0.patch
against trunk revision 685425.
+1 @author. The patch does not contain any @author tags.
-1 tests included. The patch doesn't appear to include any new or modified tests.
Please justify why no tests are needed for this patch.
-1 javadoc. The javadoc tool appears to have generated 1 warning messages.
+1 javac. The applied patch does not increase the total number of javac compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs warnings.
+1 release audit. The applied patch does not increase the total number of release audit warnings.
-1 core tests. The patch failed core unit tests.
-1 contrib tests. The patch failed contrib unit tests.
Test results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch/3058/testReport/
Findbugs warnings: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch/3058/artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Checkstyle results: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch/3058/artifact/trunk/build/test/checkstyle-errors.html
Console output: http://hudson.zones.apache.org/hudson/job/Hadoop-Patch/3058/console
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> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Commented: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Hudson (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12628865#action_12628865 ]
Hudson commented on HADOOP-3940:
--------------------------------
Integrated in Hadoop-trunk #595 (See [http://hudson.zones.apache.org/hudson/job/Hadoop-trunk/595/])
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.0
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.18.1, 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Issue Comment Edited: (HADOOP-3940) Reduce often attempts in
memory merge with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12622004#action_12622004 ]
chris.douglas edited comment on HADOOP-3940 at 8/12/08 3:19 PM:
----------------------------------------------------------------
[ edit - nevermind ]
was (Author: chris.douglas):
Alternatively, I think this could equivalently wait on {{numPendingRequests <= numRequiredMapOutputs}}, relying on close to signal the last merge
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Status: Patch Available (was: Open)
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Updated: (HADOOP-3940) Reduce often attempts in memory merge
with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Chris Douglas updated HADOOP-3940:
----------------------------------
Attachment: 3940-1.patch
Added some comments to waitForDataToMerge, particularly explaining why numRequiredMapOutputs == 0 is a special case, per Arun's suggestion.
Test failures are due to HADOOP-3946.
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Commented: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Chris Douglas (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12622004#action_12622004 ]
Chris Douglas commented on HADOOP-3940:
---------------------------------------
Alternatively, I think this could equivalently wait on {{numPendingRequests <= numRequiredMapOutputs}}, relying on close to signal the last merge
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Reporter: Chris Douglas
> Priority: Minor
> Attachments: 3940-0.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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[jira] Commented: (HADOOP-3940) Reduce often attempts in memory
merge with no work
Posted by "Owen O'Malley (JIRA)" <ji...@apache.org>.
[ https://issues.apache.org/jira/browse/HADOOP-3940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12628660#action_12628660 ]
Owen O'Malley commented on HADOOP-3940:
---------------------------------------
There was a suggestion on the list to include this in 0.18.1. That sounds right to me. Thoughts?
> Reduce often attempts in memory merge with no work
> --------------------------------------------------
>
> Key: HADOOP-3940
> URL: https://issues.apache.org/jira/browse/HADOOP-3940
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.18.0
> Reporter: Chris Douglas
> Assignee: Chris Douglas
> Priority: Minor
> Fix For: 0.19.0
>
> Attachments: 3940-0.patch, 3940-1.patch
>
>
> ReduceTask.ReduceCopier.ShuffleRamManager initializes numRequiredMapOutputs to 0, so one of the predicates in ShuffleRamManager::waitForDataToMerge, {{numPendingRequests < numRequiredMapOutputs}}, is false until the first map output is fetched and false again after the last map output is fetched. The InMemFSMergeThread thread will loop busily in this state.
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