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https://issues.apache.org/jira/browse/MAPREDUCE-1353?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12796205#action_12796205
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Amar Kamat commented on MAPREDUCE-1353:
---------------------------------------
TaskInProgress requires few getter-like information from JobInProgress which
can be passed as (method) arguments. By doing this we can get rid of the
JobInProgress back-reference in TaskInProgress and lower the effect of a TIP
reference leak atleast (see MAPREDUCE-1316).
Following are the methods where the JobInProgress object is used by
TaskInProgress
- _shouldClose()_ : Calls job.getStatus().getRunState() which can be passed as
a parameter.
- _updateStatus()_ : Requires job.hasSpeculativeMaps()/job.hasSpeculativeMaps()
which can be passed as arguments.
- _updateStatus()_ : Called from JobInProgress. Calls
job.updateStatistics(oldProgRate, currProgRate, isMapTask()) which can be
called by JobInProgress after the call to _updateStatus()_ something like
{code}
float oldProgRate = tip.getOldProgress();
tip.updateStatus(taskstatus, hasSpeculativeMaps(), hasSpeculativeReduces());
float currProgRate = tip.getOldProgress();
updateStatistics(oldProgRate, currProgRate, isMapTask()); // internal call
{code}
- _canBeSpeculated()_ : Requires job.getRunningTaskStatistics(isMapTask()) and
job.getSlowTaskThreshold() which can be passed as an argument.
- _getTaskToRun()_ : Requires job.getNumRestarts() which can be passed as an
argument.
Also TaskInProgress has a _getJob()_ api used only by the JobTracker either
for JobID or for JobInProgress. JobTracker can very well use its own _getJob()_
i.e
{code}
JobID id = tip.getJob().getJobID()
{code}
can be replaced by
{code}
JobID id = tip. getTIPId().getJobID();
{code}
and
{code}
JobInProgress jip = tip.getJob()
{code}
can be replaced by
{code}
JobInProgress jip = getJob(tip.getTIPId().getJobID());
{code}
Thoughts?
> Remove JobInProgress (back?) reference from TaskInProgress
> ----------------------------------------------------------
>
> Key: MAPREDUCE-1353
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-1353
> Project: Hadoop Map/Reduce
> Issue Type: Improvement
> Components: jobtracker
> Affects Versions: 0.22.0
> Reporter: Amar Kamat
> Assignee: Amar Kamat
> Fix For: 0.22.0
>
>
> Looks like TaskInProgress can get rid of JobInProgress back-reference if the
> values it requires from the JobInProgress are passed as parameters.
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