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Date: Wed, 23 Jun 2010 09:44:50 -0700
Message-ID: <AANLkTineG03L0fgP0kUw8iujW01-WQS-UqnVFRrOJuiO@mail.gmail.com>
Subject: Re: Why data read performs better than data write in HBase?
From: Jean-Daniel Cryans <jdcryans@apache.org>
To: dev@hbase.apache.org
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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, =E5=8F=B2=E8=8B=B1=E6=9D=B0 <shiyingjie198=
3@gmail.com> wrote:
> Hi, All
> =C2=A0 =C2=A0Recently I did some tests on HBase, using the performance ev=
eluation
> package =C2=A0in HBase 0.20.3. There are some situations I can't understa=
nd. 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 bett=
er
> than reads, because each tablet server appends all incoming writes to a
> single commit log and uses group commit to stream these writes efficientl=
y
> to GFS. In HBase, we set the autoFlush=3Dfalse, 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
>