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From "Goel, Ankur" <Ankur.G...@corp.aol.com>
Subject RE: Filter omitting columns
Date Fri, 21 Mar 2008 13:02:24 GMT
Clint,
      Thanks! The patch works and I am able to get the remaining columns
successfully.
One question though, it seems like the behaviour is different from what
I expected.
I wanted something like

Select url:, status:, from mytable where status=0;

It is correctly able to filter out the status values <> 0 but the 'url:'

column values are untouched !

Coming from an RDBMS background, I was hoping that the application of
column
filter would yield similar result! (fetching only those 'url:' column
values
for which 'status:' matched)

In a column oriented database like Hbase, should such scenario be
catered manually ?
For e.g ignoring 'url:' values if 'status:' value got filtered ?

Is there a tutorial available that shows 2-3 tables in RDBMS style and
then transforms them into column oriented design ?

Thanks
-Ankur





-----Original Message-----
From: Clint Morgan [mailto:clint.a.m@gmail.com] 
Sent: Thursday, March 20, 2008 10:11 PM
To: hbase-user@hadoop.apache.org
Subject: Re: Filter omitting columns

Thats great, but it won't do what he wants, as he want only rows where
the value for the status: column  equals getBytes(1). Hence the filter.

On Thu, Mar 20, 2008 at 9:30 AM, Jim Kellerman <jim@powerset.com> wrote:
> If you want to get all the family members, you can just specify  
> 'familyname:' as the column. This creates a wild-card scanner  which 
> will do what you want without filters.
>
>  ---
>  Jim Kellerman, Senior Engineer; Powerset
>
>
>
>
>  > -----Original Message-----
>  > From: Clint Morgan [mailto:clint.a.m@gmail.com]  > Sent: Thursday, 
> March 20, 2008 9:19 AM  > To: hbase-user@hadoop.apache.org  > Subject:

> Re: Filter omitting columns  >  > I was having a similar problem as 
> well. Though I've never  > used just the column families to specify 
> the columns (eg  > always fully qualified col names like family:col) .

> Maybe you  > can try my patch and see if it fixes your problem.
>  >
>  > https://issues.apache.org/jira/browse/HBASE-527
>  >
>  > Also you can give a null value for the row key regexp if you  > 
> don't want to use it in RegExpRowFilter.
>  >
>  > -clint
>  >
>  > On Thu, Mar 20, 2008 at 7:23 AM, Goel, Ankur  > 
> <Ankur.Goel@corp.aol.com> wrote:
>  > >
>  > >  Hi,
>  > >    I am trying to obtain a set of rows by obtaining a scanner  on
>  > > Htable. I also specify the RowFilterCriteria like this.
>  > >
>  > >  /* Code Start */
>  > >  Map<Text, byte[]> columnFilter = new HashMap<Text, byte[]>();
 >

> > columnFilter.put(new Text("status:"), getBytes(1));  > > 
> RowFilterInterface rowFilter = new RegExpRowFilter(".*",  > > 
> columnFilter);  > >  > >  HTable myTable = new HTable(conf, new 
> Text("myTable"));  Text[]  > > columns = {new Text("url:"), new 
> Text("status:")};  > > myTable.obtainScanner(columns, 
> HConstants.EMPTY_START_ROW,  > rowFilter);  > >  /* Code End */  > > 

> > >  When I scan the table, I only get 'status:' column family and its

> > > values.
>  > >  The 'url:' family is not present.
>  > >
>  > >  In simple SQL the query translates to something like  > >  > >
 
> SELECT url, status FROM mytable WHERE status=1;  > >  > >  What could 
> be wrong ?
>  > >
>  > >  I eventually want to do something like this  > >  > >  SELECT

> url, status, date FROM mytable WHERE (status=1 or (status=2  > > and  
> [today's date] > date));  > >  > >  I have used RowFilterSet with 
> RowFilterSet.Operation options to  > > accomplish this but the 
> omission  of columns not on the  > filter column  > > list by the 
> filter beats me.
>  > >
>  > >  Thanks
>  > >  -Ankur
>  > >
>  >
>  > No virus found in this incoming message.
>  > Checked by AVG.
>  > Version: 7.5.519 / Virus Database: 269.21.7/1335 - Release  > Date:

> 3/19/2008 9:54 AM  >  >
>
>  No virus found in this outgoing message.
>  Checked by AVG.
>  Version: 7.5.519 / Virus Database: 269.21.7/1335 - Release Date: 
> 3/19/2008 9:54 AM
>
>

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