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From Ramasubramanian Narayanan <ramasubramanian.naraya...@gmail.com>
Subject Re: Regarding rework in changing column family
Date Wed, 28 Nov 2012 05:48:44 GMT
Thanks Ram!!!

My question is like this...

suppose I have create a table with 100 columns with single column family
'cf1',

now in production there are billions of records are there in that table and
there are mulitiple programs that is feeding into this table (let us take
some 50 programs)...

In this scenario, if I change the column family like first 40 columns let
it be in 'cf1', the last 60 columns I want to move to new column family
'cf2', in this case, *do we need to change all 50 programs which are
inserting into that table with 'cf1' for all columns?*
*
*
regards,
Rams

On Wed, Nov 28, 2012 at 10:24 AM, ramkrishna vasudevan <
ramkrishna.s.vasudevan@gmail.com> wrote:

> As far as i see altering the table with the new columnfamily should be
> easier.
> -> disable the table
> -> Issue modify table command with the new col family.
> -> run a compaction.
> Now after this when you start doing your puts, they should be in alignment
> with the new schema defined for the table.  You may have to see one thing
> is how much your rate of puts is getting affected because now both of your
> CFs will start flushing whenever a memstore flush happens.
>
> Hope this helps.
>
> Regards
> Ram
>
> On Wed, Nov 28, 2012 at 10:10 AM, Ramasubramanian <
> ramasubramanian.narayanan@gmail.com> wrote:
>
> > Hi,
> >
> > I have created table in hbase with one column family and planned to
> > release for development (in pentaho).
> >
> > Suppose later after doing the data profiling in production if I feel that
> > out of 600 columns 200 is not going to get used frequently I am planning
> to
> > group those into another column family.
> >
> > If I change the column family at later point of time I hope there will a
> > lots of rework that has to be done (either if we use java or pentaho). Is
> > my understanding is correct? Is there any other alternative available to
> > overcome?
> >
> > Regards,
> > Rams
>

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