[jira] [Commented] (TEZ-1911) MergeManager's unconditionalReserve() should check for memory limits before allocating memory to IntermediateMemoryToMemoryMerger

["TezQA (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TEZ-1911?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15151700#comment-15151700 ] 

TezQA commented on TEZ-1911:
----------------------------

{color:red}-1 overall{color}.  Here are the results of testing the latest attachment
  http://issues.apache.org/jira/secure/attachment/12788364/TEZ-1911.1.patch
  against master revision de3a074.

    {color:green}+1 @author{color}.  The patch does not contain any @author tags.

    {color:green}+1 tests included{color}.  The patch appears to include 1 new or modified test files.

    {color:green}+1 javac{color}.  The applied patch does not increase the total number of javac compiler warnings.

    {color:green}+1 javadoc{color}.  There were no new javadoc warning messages.

    {color:red}-1 findbugs{color}.  The patch appears to introduce 1 new Findbugs (version 3.0.1) warnings.

    {color:green}+1 release audit{color}.  The applied patch does not increase the total number of release audit warnings.

    {color:red}-1 core tests{color}.  The patch failed these unit tests in :
                   org.apache.tez.test.TestTezJobs

Test results: https://builds.apache.org/job/PreCommit-TEZ-Build/1476//testReport/
Findbugs warnings: https://builds.apache.org/job/PreCommit-TEZ-Build/1476//artifact/patchprocess/newPatchFindbugsWarningstez-runtime-library.html
Console output: https://builds.apache.org/job/PreCommit-TEZ-Build/1476//console

This message is automatically generated.

> MergeManager's unconditionalReserve() should check for memory limits before allocating memory to IntermediateMemoryToMemoryMerger
> ---------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: TEZ-1911
>                 URL: https://issues.apache.org/jira/browse/TEZ-1911
>             Project: Apache Tez
>          Issue Type: Bug
>            Reporter: Rajesh Balamohan
>            Assignee: Rajesh Balamohan
>         Attachments: TEZ-1911.1.patch
>
>
> Currently, IntermediateMemoryToMemoryMerger invokes unconditionalReserve() to get the memory needed for intermediate mem-to-mem merging.  It could potentially cause issue in the following scenario
> 1. tez.runtime.io.sort.factor set to 100 and assume shuffled data (e.g 60% memory occupied) haven't reached TEZ_RUNTIME_SHUFFLE_MERGE_PERCENT_DEFAULT
> 2. Assume that it reaches the sort.factor threshold before reaching merge threshold.  This would kick in IntermediateMemoryToMemoryMerger.
> In IntermediateMemoryToMemoryMerger, it would try to allocate additional 60% without any boundary checks.  This could lead to OOM depending on the tez.runtime.io.sort.mb setting.



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