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From Pavan Sudheendra <pavan0...@gmail.com>
Subject Re: How to get row key from row value?
Date Wed, 31 Jul 2013 14:02:37 GMT
So a secondary table here is more of a temporary table which I can just do
a get operation and get the value?

Am I right?

Regards,
Pavan
On Jul 31, 2013 7:24 PM, "Shahab Yunus" <shahab.yunus@gmail.com> wrote:

> Please correct me if I am wrong but I think there is as such no hard and
> fast technique for it. There are no constructs or method to this
> specifically in HBase. Your client while writing have to make sure to write
> to both tables: 1) the main table 2) and the secondary index table.
> Basically it is up to you according to the use-case and application. You
> can delegate this to a sort of a middle (separate layer from client app at
> least) which takes care of maintaing consistency between the two tables.
> This layer will be used for both read and write to implement and handle
> your indexing. The one obvious issue that you need to take into
> consideration is atomicity and consistency of the two tables.
>
> Regards,
> Shahab
>
>
> On Wed, Jul 31, 2013 at 9:37 AM, Pavan Sudheendra <pavan0591@gmail.com
> >wrote:
>
> > Yes perfect. Could i get few examples on how to create a secondary lookup
> > table?
> >
> >
> > On Wed, Jul 31, 2013 at 7:01 PM, Jean-Marc Spaggiari
> > <jean-marc@spaggiari.org> wrote:
> > > Hi Pavan,
> > >
> > > for your lookup table, you need to lookup on the value? Not on the
> they?
> > If
> > > that's the case, just "revert" your table into a secondary index lookup
> > > table where the value will be the key, and the key will be the value.
> > That
> > > way you just to a get on this secondary index lookup table instead of
> > doing
> > > a scan...
> > >
> > > Make sense?
> > >
> > > JM
> > >
> > > 2013/7/31 Pavan Sudheendra <pavan0591@gmail.com>
> > >
> > >> Before inserting a row in my main table, i need to do a lookup on my
> > >> lookup table. I'm really not sure what logic has to be behind this.
> > >> Should i do a full table scan of the lookup table every single time i
> > >> insert in the main table?
> > >>
> > >> Thanks jean
> > >>
> > >>
> > >>
> > >> On Wed, Jul 31, 2013 at 6:10 PM, Jean-Marc Spaggiari
> > >> <jean-marc@spaggiari.org> wrote:
> > >> > the best way is to insert on your lookup table each time you insert
> on
> > >> your
> > >> > main table. That way you don't have to scan your entire main table
> to
> > >> build
> > >> > the lookup table...
> > >> >
> > >> > If you want to filter by CF you can look at
> > >> >
> > >>
> >
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/FamilyFilter.html
> > >> > .
> > >> >
> > >> > Basically, you have all the filters listed there:
> > >> >
> > >>
> >
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/package-summary.html
> > >> >
> > >> > You should be able to find one which match your needs.
> > >> >
> > >> > JM
> > >> >
> > >> > 2013/7/31 Pavan Sudheendra <pavan0591@gmail.com>
> > >> >
> > >> >> Hi Jean,
> > >> >> Is there a way to specify column family, column qualifier and
> column
> > >> >> value to get the row key without having to scan the table every
> > single
> > >> >> time?
> > >> >> Basically, i'm building a lookup table which helps in insertion
of
> > >> >> another HBase table. its quite complicated to explain.
> > >> >>
> > >> >> On Wed, Jul 31, 2013 at 5:53 PM, Jean-Marc Spaggiari
> > >> >> <jean-marc@spaggiari.org> wrote:
> > >> >> > Hi Pavan,
> > >> >> >
> > >> >> > Are you looking for something like
> > >> >> >
> > >> >>
> > >>
> >
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/ValueFilter.html
> > >> >> ?
> > >> >> >
> > >> >> > You are going to do a table full scan... If you value is
uniq,
> you
> > >> might
> > >> >> > want to build a secondary index table for direct access...
> > >> >> >
> > >> >> > JM
> > >> >> >
> > >> >> > 2013/7/31 Pavan Sudheendra <pavan0591@gmail.com>
> > >> >> >
> > >> >> >> How do i get the row key by specifying a row value assuming
row
> > >> values
> > >> >> >> are unique?
> > >> >> >>
> > >> >> >> What API should i use for this purpose?
> > >> >> >> --
> > >> >> >> Regards-
> > >> >> >> Pavan
> > >> >> >>
> > >> >>
> > >> >>
> > >> >>
> > >> >> --
> > >> >> Regards-
> > >> >> Pavan
> > >> >>
> > >>
> > >>
> > >>
> > >> --
> > >> Regards-
> > >> Pavan
> > >>
> >
> >
> >
> > --
> > Regards-
> > Pavan
> >
>

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