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From lohit <lohit.vijayar...@gmail.com>
Subject Re: Hive Query with UDF
Date Thu, 18 Oct 2012 02:13:47 GMT
One idea is to write your own translation layer  which sits in between
query and actual job submission.
You would most likely end up having your own version of hive jar which has
your translation changes on top of HIVE sources.
This has the added advantage that users need not change their queries, they
would do it as normal HIVE query, like
   select * from cc_details where first_name = 'Ann'
Disadvantage is you have to maintain a fork.

Even otherwise, my initial guess is you might have to modify command line
parser which does encrypt once instead of for every record

2012/10/17 Sam Mohamed <sam.mohamed@voltage.com>

> Thanks for the quick response.
>
> The idea is that we are selling the encryption product for customers who
> use HDFS.  Hence, encryption is a requirement.
>
> Any other suggestions.
>
> Sam
> ________________________________________
> From: Michael Segel [michael_segel@hotmail.com]
> Sent: Wednesday, October 17, 2012 6:10 PM
> To: user@hadoop.apache.org
> Subject: Re: Hive Query with UDF
>
> You don't need an UDF...
>
> You encrypt the string 'Ann' first then use that encrypted value in the
> Select statement.
>
> That should make things a bit simpler.
>
>
>
> On Oct 17, 2012, at 8:04 PM, Sam Mohamed <sam.mohamed@voltage.com> wrote:
>
> > I have some encrypted data in an HDFS csv, that I've created a Hive
> table for, and I want to run a Hive query that first encrypts the query
> param, then does the lookup.  I have a UDF that does encryption as follows:
> >
> > public class ParamEncrypt extends UDF {
> >
> >  public Text evaluate(String name) throws Exception {
> >
> >      String result = new String();
> >
> >      if (name == null) { return null; }
> >
> >      result = ParamData.encrypt(name);
> >
> >      return new Text(result);
> >  }
> > }
> >
> > Then I run the Hive query as:
> >
> >  select * from cc_details where first_name = encrypt('Ann');
> >
> > The problem is, it's running encrypt('Ann') across every single record
> in the table.  I want it do the encryption once, then do the matchup.  I've
> tried:
> >
> >  select * from cc_details where first_name in (select encrypt('Ann')
> from cc_details limit 1);
> >
> > But Hive doesn't support **IN** or select queries in the where clause.
> >
> > What can I do?
> >
> > Can I do something like:
> >
> >  select encrypt('Ann') as ann from cc_details where first_name = ann;
> >
> > That also doesn't work because the query parser throws an error saying
> **ann** is not a known column
> >
> > Thanks,
> >
> > Sam
>
>


-- 
Have a Nice Day!
Lohit

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