Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase, mail # user - Is get a private case of scan ?


Copy link to this message
-
Re: Is get a private case of scan ?
Amit Sela 2014-01-16, 21:29
I'm managing splitting manually and my algorithm ensures that.
On Jan 16, 2014 10:34 PM, "Ted Yu" <[EMAIL PROTECTED]> wrote:

> bq. be sure the second rowkey will be in the same region
>
> See 9.7.4.1 in http://hbase.apache.org/book.html#arch.region.splits
>
>
> On Thu, Jan 16, 2014 at 10:58 AM, Asaf Mesika <[EMAIL PROTECTED]>
> wrote:
>
> > You also can't be sure the second rowkey will be in the same region which
> > is requires you to go on the network to another region server.
> >
> > On Thursday, January 16, 2014, Amit Sela <[EMAIL PROTECTED]> wrote:
> >
> > > I have a case where I want to "split" rows with a lot of qualifiers (a
> > very
> > > small amount of rows < 1%, with an exceptional number of qualifiers),
> > into
> > > a number of rows. Say like:
> > > row1.....
> > > row1_DELIMITER_UUID
> > > row1_DELIMITER_UUID2
> > > row2
> > > I was thinking of using a postGet() RegionObserver (the "split" rows
> will
> > > always be stored in the same region) but when digging into the code I
> > > noticed that Get is a Scan so I was wondering why not just scan for all
> > > row1s ?
> > >
> > >
> > > On Wed, Jan 15, 2014 at 10:53 PM, Stack <[EMAIL PROTECTED]
> <javascript:;>>
> > > wrote:
> > >
> > > > On Wed, Jan 15, 2014 at 5:34 AM, Amit Sela <[EMAIL PROTECTED]
> > <javascript:;>>
> > > wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > I was wondering if Get is implemented as a private case of scan ?
> > > > > In HRegion, I see that the get passed is used to construct a Scan
> > > object
> > > > > for the RegionScanner to use.
> > > > >
> > > > >
> > > > A Get is a Scan, yes.
> > > >
> > > >
> > > > > I was wondering if executing Scan(Get) vs Get from client api
> should
> > > have
> > > > > any overhead ?
> > > > >
> > > >
> > > > There are differences in that 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).
> > > >
> > > > Why do you want to Scan(Get) instead of Get?
> > > >
> > > > St.Ack
> > > >
> > >
> >
>