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From Arpit Agarwal <aagar...@hortonworks.com>
Subject Re: [VOTE] Merge HDFS-6581 to trunk - Writing to replicas in memory.
Date Fri, 26 Sep 2014 01:43:28 GMT
Andrew, I think you are reading hostility or lack of warmth where it wasn't
intended. I apologize if it came through in my responses to you. Please
consider that it could be due to the limitations of communicating over

Your technical feedback is always welcome and I thank you for it again, as
I did on the Jira and in my vote email.


On Thu, Sep 25, 2014 at 5:54 PM, Andrew Wang <andrew.wang@cloudera.com>

> -0.
> The goal of this feature is to improve write performance. I thought it was
> thus reasonable for me to ask for write benchmarks. However, this request
> was not received warmly. For a performance oriented feature, I expected
> that benchmarks would have been run both to guide the design and evaluate
> the implementation. Doing so only after a merge vote is called, and only
> after repeated requests, is unorthodox to say the least.
> My questions about plans to further improve performance were also not
> received warmly. Based on the microbenchmark results, we're still not at a
> significant fraction of memory bandwidth. What I've been looking for are
> plans to get us there, so we could evaluate how those plans might interact
> with this feature. I know Arpit had prototyped short-circuit writes a while
> ago, and SCW has the potential to take us well past 39% gains. However,
> apparently there are no future plans in this direction.
> So, -0. I think this merge vote was called prematurely, and some of the
> merge-related interactions have had a tinge of hostility. However, I also
> agree with Suresh that merging this will likely not affect the stability of
> existing features, and ultimately, I respect all of you as developers and
> clearly you all want this in now. I've always valued our collaboration on
> the project and I hope can continue fruitfully into the future, I just also
> hope we can do it with the intensity dialed down.
> Best,
> Andrew

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