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HBase >> mail # user >> Tall good with Scans, Wide good with Gets???


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Re: Tall good with Scans, Wide good with Gets???
Thanks Ted, This jira helped me to understand that claim much better now.
On Wed, Jan 22, 2014 at 1:10 PM, Ted Yu <[EMAIL PROTECTED]> wrote:

> For the follow-on question of #1, see HBASE-9488 : small scan.
>
> Cheers
>
>
> On Wed, Jan 22, 2014 at 10:30 AM, Tianying Chang <[EMAIL PROTECTED]>
> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
> > > 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
> > > >
> > >
> >
>