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From William Kang <weliam.cl...@gmail.com>
Subject Re: Questions about HBase
Date Tue, 02 Mar 2010 03:36:42 GMT
And another question, why the ROOT table and META tables are not in the
HBaseMaster's memory? Would this greatly degrade the performance?
Thanks.


William


On Mon, Mar 1, 2010 at 5:33 PM, Erik Holstad <erikholstad@gmail.com> wrote:

> On Mon, Mar 1, 2010 at 2:16 PM, Ryan Rawson <ryanobjc@gmail.com> wrote:
>
> > Hi,
> >
> > 1.  We use in-memory indexes to get fast random reads.  Our index
> > tells us to read block X of a file only retrieving a small amount of
> > the file to satisfy the user's read.
> >
> > 2.  The row locking is not global - for each row there can only be 1
> > thread doing a put at a time.  This serializes all puts to a single
> > row. It is NOT global.
> >
>
> So, this is me not understanding the difference between global locking and
> waiting in a line until the tasks ahead of you are done :)
>
> >
> > On Mon, Mar 1, 2010 at 12:36 PM, William Kang <weliam.cloud@gmail.com>
> > wrote:
> > > Hi guys,
> > > I am new to HBase and have several questions. Would anybody kindly
> answer
> > > some of them?
> > >
> > > 1. Why HBase could provide a low-latency random access to files
> compared
> > to
> > > HDFS?
> > >
> > > 2. By default, Only a single row at a time may be locked. Is it a
> single
> > > client who can only lock one or is it globally can only lock one?  If
> > this
> > > is the case, by default, will the performance be really bad?
> > >
> > > Many thanks!
> > >
> > >
> > > William
> > >
> >
>
>
>
> --
> Regards Erik
>

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