[jira] [Commented] (MAPREDUCE-2512) wait(5000) and notify() mechanism can be implemented instead of sleep(5000) in reduce task when there are no copies in progress and no new copies to schedule
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https://issues.apache.org/jira/browse/MAPREDUCE-2512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13045101#comment-13045101
]
Todd Lipcon commented on MAPREDUCE-2512:
As this is an optimization, you should prepare a patch against trunk if the
issue exists there. We don't generally put optimizations backward into prior
releases.
wait(5000) and notify() mechanism can be implemented instead of sleep(5000)
in reduce task when there are no copies in progress and no new copies to
schedule
-
Key: MAPREDUCE-2512
URL: https://issues.apache.org/jira/browse/MAPREDUCE-2512
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: task
Affects Versions: 0.20.2
Reporter: Devaraj K
Assignee: Devaraj K
Fix For: 0.20.4
Attachments: MAPREDUCE-2512.patch
{code:title=ReduceTask.java|borderStyle=solid}
try {
if (numInFlight == 0 numScheduled == 0) {
// we should indicate progress as we don't want TT to think
// we're stuck and kill us
reporter.progress();
Thread.sleep(5000);
}
} catch (InterruptedException e) { } // IGNORE
{code}
Here if we have no copies in flight and we can't schedule anything new, it is
going to wait for 5000 millis. Instead of waiting for 5000 millis, this
thread can wait with timeout and GetMapEventsThread can notify it if gets new
map completion events earlier than 5000 millis time.
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[jira] [Commented] (MAPREDUCE-2512) wait(5000) and notify() mechanism can be implemented instead of sleep(5000) in reduce task when there are no copies in progress and no new copies to schedule
[
https://issues.apache.org/jira/browse/MAPREDUCE-2512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13043375#comment-13043375
]
Hadoop QA commented on MAPREDUCE-2512:
--
-1 overall. Here are the results of testing the latest attachment
http://issues.apache.org/jira/secure/attachment/12481348/MAPREDUCE-2512.patch
against trunk revision 1130994.
+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 new tests are needed for this
patch.
Also please list what manual steps were performed to
verify this patch.
-1 patch. The patch command could not apply the patch.
Console output:
https://builds.apache.org/hudson/job/PreCommit-MAPREDUCE-Build/343//console
This message is automatically generated.
wait(5000) and notify() mechanism can be implemented instead of sleep(5000)
in reduce task when there are no copies in progress and no new copies to
schedule
-
Key: MAPREDUCE-2512
URL: https://issues.apache.org/jira/browse/MAPREDUCE-2512
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: task
Affects Versions: 0.20.2
Reporter: Devaraj K
Assignee: Devaraj K
Fix For: 0.20.4
Attachments: MAPREDUCE-2512.patch
{code:title=ReduceTask.java|borderStyle=solid}
try {
if (numInFlight == 0 numScheduled == 0) {
// we should indicate progress as we don't want TT to think
// we're stuck and kill us
reporter.progress();
Thread.sleep(5000);
}
} catch (InterruptedException e) { } // IGNORE
{code}
Here if we have no copies in flight and we can't schedule anything new, it is
going to wait for 5000 millis. Instead of waiting for 5000 millis, this
thread can wait with timeout and GetMapEventsThread can notify it if gets new
map completion events earlier than 5000 millis time.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (MAPREDUCE-2512) wait(5000) and notify() mechanism can be implemented instead of sleep(5000) in reduce task when there are no copies in progress and no new copies to schedule
[
https://issues.apache.org/jira/browse/MAPREDUCE-2512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13036751#comment-13036751
]
Devaraj K commented on MAPREDUCE-2512:
--
This try/catch is not related to the any stuck tasks. If there are no map
outputs ready to copy, this thread goes to sleep state for 5000 millis and then
continue execution after timeout. When this thread is in sleep state, if any
thread performs some operation (like interrupt (), stop ()) on this thread, it
will throw InterruptedException and comes out from the sleep state. After
getting InterruptedException, it will ignore and continue execution normally.
This thread waits for 5000 millis even If it gets new map completion events
before 5000 millis. This can be optimized such that,
{code:title=ReduceTask.java|borderStyle=solid}
reporter.progress();
- Thread.sleep(5000);
+ synchronized (lockCopy) {
+lockCopy.wait(5000);
+ }
}
} catch (InterruptedException e) { } // IGNORE
int numNewMaps = getMapCompletionEvents();
if (numNewMaps 0) {
+ synchronized (lockCopy) {
+lockCopy.notify();
+ }
LOG.info(reduceTask.getTaskID() + : +
Got + numNewMaps + new map-outputs);
{code}
wait(5000) and notify() mechanism can be implemented instead of sleep(5000)
in reduce task when there are no copies in progress and no new copies to
schedule
-
Key: MAPREDUCE-2512
URL: https://issues.apache.org/jira/browse/MAPREDUCE-2512
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: task
Affects Versions: 0.20.2
Reporter: Devaraj K
Assignee: Devaraj K
{code:title=ReduceTask.java|borderStyle=solid}
try {
if (numInFlight == 0 numScheduled == 0) {
// we should indicate progress as we don't want TT to think
// we're stuck and kill us
reporter.progress();
Thread.sleep(5000);
}
} catch (InterruptedException e) { } // IGNORE
{code}
Here if we have no copies in flight and we can't schedule anything new, it is
going to wait for 5000 millis. Instead of waiting for 5000 millis, this
thread can wait with timeout and GetMapEventsThread can notify it if gets new
map completion events earlier than 5000 millis time.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (MAPREDUCE-2512) wait(5000) and notify() mechanism can be implemented instead of sleep(5000) in reduce task when there are no copies in progress and no new copies to schedule
[
https://issues.apache.org/jira/browse/MAPREDUCE-2512?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanelfocusedCommentId=13035559#comment-13035559
]
Allen Wittenauer commented on MAPREDUCE-2512:
-
Could this try/catch block be related to the stuck tasks we sometimes see?
What sort of exceptions are InterruptedException?
wait(5000) and notify() mechanism can be implemented instead of sleep(5000)
in reduce task when there are no copies in progress and no new copies to
schedule
-
Key: MAPREDUCE-2512
URL: https://issues.apache.org/jira/browse/MAPREDUCE-2512
Project: Hadoop Map/Reduce
Issue Type: Improvement
Components: task
Affects Versions: 0.20.2
Reporter: Devaraj K
Assignee: Devaraj K
{code:title=ReduceTask.java|borderStyle=solid}
try {
if (numInFlight == 0 numScheduled == 0) {
// we should indicate progress as we don't want TT to think
// we're stuck and kill us
reporter.progress();
Thread.sleep(5000);
}
} catch (InterruptedException e) { } // IGNORE
{code}
Here if we have no copies in flight and we can't schedule anything new, it is
going to wait for 5000 millis. Instead of waiting for 5000 millis, this
thread can wait with timeout and GetMapEventsThread can notify it if gets new
map completion events earlier than 5000 millis time.
--
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For more information on JIRA, see: http://www.atlassian.com/software/jira
