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From Arun Allamsetty <arun.allamse...@gmail.com>
Subject Re: HBase appends
Date Wed, 23 Jul 2014 02:57:19 GMT
That's true. I never thought of it that way. Thanks for pointing it out.

Arun
On Jul 22, 2014 4:07 PM, "Ted Yu" <yuzhihong@gmail.com> wrote:

> When storing new lists using new columns, similar issue would arise, right
> ?
> In Ishan's words:
>
> bq. read all the columns and combine when reading
>
> The combining process applies to the multi-version approach as well.
>
> Cheers
>
>
> On Tue, Jul 22, 2014 at 12:32 PM, Arun Allamsetty <
> arun.allamsetty@gmail.com
> > wrote:
>
> > Hi,
> >
> > Isn't versioning used for an entirely different purpose? What if I screw
> up
> > a book name and then have to rewrite it? Then I'll have two versions for
> > the same book. Also, AFAIK the default number of versions is 1 on table
> > creation without additional parameters.
> >
> > Thanks,
> > Arun
> > On Jul 22, 2014 12:11 PM, "yonghu" <yongyong313@gmail.com> wrote:
> >
> > > Hi,
> > >
> > > If a author does not have hundreds of publications, you can directly
> > write
> > > in one column. Hence, your column will contain multiple data versions.
> > The
> > > default data version is 3 but you can send more.
> > >
> > >
> > > On Tue, Jul 22, 2014 at 4:20 AM, Ishan Chhabra <
> ichhabra@rocketfuel.com>
> > > wrote:
> > >
> > > > Arun,
> > > > You need to represent your data in a format such that you can simply
> > add
> > > a
> > > > byte[] to the end of the existing byte[] in a Cell and later read and
> > > > decode it as a list.
> > > >
> > > > One way is to use the encode your data as protobuf. When you append a
> > > list
> > > > of values in byte[] form in protobuf to an existing list byte[] and
> > read
> > > > the combined byte[], it is automatically recognized as one single
> list
> > > due
> > > > to the way protobuf encodes lists.
> > > >
> > > > Another way to solve this problem is write a new column for each
> > appended
> > > > list and read all the columns and combine when reading. (I prefer
> this
> > > > approach since the way Append is implemented internally, it can lead
> to
> > > > high memstore usage).
> > > >
> > > >
> > > > On Mon, Jul 21, 2014 at 5:43 PM, Arun Allamsetty <
> > > > arun.allamsetty@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > If I have a one-to-many relationship in a SQL database (an author
> > might
> > > > > have written many books), and I want to denormalize it for writing
> in
> > > > > HBase, I'll have a table with the Author as the row key and a
> *list*
> > of
> > > > > books as values.
> > > > >
> > > > > Now my question is how do I create a *list* such that I could just
> > > append
> > > > > to it using the HBase Java API *Append* instead of doing a
> > > > > read-modify-insert on a Java List object containing all the books.
> > > > >
> > > > > Thanks,
> > > > > Arun
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > *Ishan Chhabra *| Rocket Scientist | RocketFuel Inc.
> > > >
> > >
> >
>

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