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From Ted Yu <yuzhih...@gmail.com>
Subject Re: Tall good with Scans, Wide good with Gets???
Date Wed, 22 Jan 2014 21:10:51 GMT
For the follow-on question of #1, see HBASE-9488 : small scan.

Cheers


On Wed, Jan 22, 2014 at 10:30 AM, Tianying Chang <tychang@gmail.com> wrote:

> Ted, Thanks for link!
>
> 1. the post said "Get will pread from HDFS where Scan will seek and read
> under lock (and only fall back to pread when it notices contention on the
> hfile)." It seems pread  is for highly concurrent small readers.  So this
> brings me a new question: does this mean that if my scan startKey/endKey
> only covers 10 rows, it is faster to run a getMultiple()???
>
>
> 2. Still confused why Tall is good for Scans, wide is good for Gets? I
> thought the underlying storage is stored in KV. so tall or wide shouldn't
> matter, right?
>
> Thanks
> Tian-Ying
>
>
> On Wed, Jan 22, 2014 at 10:12 AM, Ted Yu <yuzhihong@gmail.com> wrote:
>
> > See
> >
> >
> http://search-hadoop.com/m/nAAad2wRi03/Is+get+a+private+case+of+scan&subj=Re+Is+get+a+private+case+of+scan+
> >
> > Cheers
> >
> >
> > On Wed, Jan 22, 2014 at 10:09 AM, Tianying Chang <tychang@gmail.com>
> > wrote:
> >
> > > Hi,
> > >
> > > I watched this youtube video
> http://www.youtube.com/watch?v=_HLoH_PgrLkby
> > > Lars George. It is really good one!
> > >
> > > I just have one thing still cannot understand. It said Tall is good for
> > > Scan, Wide is good for Get. My understanding is that Scan and Get is
> > using
> > > the same code underlying. It first seek to the specific kv, check data,
> > > after done, then do next() . Considering the underlying storage is same
> > for
> > > wide or tall, and the code to do scan/get is the same. why Tall is good
> > for
> > > Scan, and wide is good for Get?
> > >
> > > Does anyone know why? This really puzzles me.
> > >
> > > Thanks a lot!
> > > Tian-Ying
> > >
> >
>

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