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From Jean-Daniel Cryans <jdcry...@apache.org>
Subject Re: Why data read performs better than data write in HBase?
Date Wed, 23 Jun 2010 16:44:50 GMT
When I run PE, random/seqRead are always much slower than
random/seqWrite so it seems to be something about your env or you are
confused by the output of that test.

What are the numbers you see?

J-D

On Wed, Jun 23, 2010 at 5:32 AM, 史英杰 <shiyingjie1983@gmail.com> wrote:
> Hi, All
>    Recently I did some tests on HBase, using the performance eveluation
> package  in HBase 0.20.3. There are some situations I can't understand. I
> found that read perform better than write, no matter sequential read or
> random read during the test. But in BigTable's paper, writes perform better
> than reads, because each tablet server appends all incoming writes to a
> single commit log and uses group commit to stream these writes efficiently
> to GFS. In HBase, we set the autoFlush=false, and the flush size is 64M, so
> writes should perform better than reads, but the result is just the
> opposite. Please help me to explain this phenomenon, thanks a lot!
>
> Yingjie
>

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