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https://issues.apache.org/jira/browse/TEZ-699?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14046395#comment-14046395
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Hitesh Shah commented on TEZ-699:
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Thanks [~rohini]. I was just debating the use of Xms with [~sseth] offline as
to whether the initial memory pre-allocation would end up causing more memory
pressure as compared to when only Xmx is defined. However, setting Xms does
have performance benefits. In a case where it is not set, the default size is I
believe is around 256 MB ( can be checked by running "java
-XX:+PrintFlagsFinal | grep -i Heap" ). This would end up causing frequent
expansions of the heap.
I will leave out Xms for now given that you have strong concerns on its
potential negative impact.
Would you be willing to try out some different settings such as Xms to be 25%
or 40% on your test clusters to see what kind of impact it has and whether a
default fractional value for Xms is useful?
> Have sensible defaults for java opts
> ------------------------------------
>
> Key: TEZ-699
> URL: https://issues.apache.org/jira/browse/TEZ-699
> Project: Apache Tez
> Issue Type: Sub-task
> Reporter: Bikas Saha
> Assignee: Hitesh Shah
> Attachments: TEZ-699.1.patch
>
>
> Its a burden to have to specify them all the time. API's already exist if
> users want to set special values. Also, for vertex memory would be good to
> have a TezUtils.getDefaultVertexResource() with a sensible resource size.
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