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From Ted Yu <yuzhih...@gmail.com>
Subject Re: HBase appends
Date Tue, 22 Jul 2014 22:07:15 GMT
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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