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HBase, mail # user - SingleColumnValueFilter for empty column qualifier


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Re: SingleColumnValueFilter for empty column qualifier
Jonathan Bishop 2012-11-01, 18:30
Hi,

Thanks for the help.

I am going forward with writing my own filter - but having some trouble
running it. What I did was simply copied SingleValueColumnFilter, renamed
it, and ran. But I got...

Exception in thread "main"
org.apache.hadoop.hbase.client.RetriesExhaustedException: Failed after
attempts=10, exceptions:
Thu Nov 01 11:18:29 PDT 2012,
org.apache.hadoop.hbase.client.ScannerCallable@2be2befa,
java.io.IOException: IPC server unable to read call parameters: Error in
readFields
Thu Nov 01 11:18:30 PDT 2012,
org.apache.hadoop.hbase.client.ScannerCallable@2be2befa,
java.io.IOException: IPC server unable to read call parameters: Error in
readFields
Thu Nov 01 11:18:31 PDT 2012,
org.apache.hadoop.hbase.client.ScannerCallable@2be2befa,
java.io.IOException: IPC server unable to read call parameters: Error in
readFields

Here is how I run it...

java -cp Graph/bin:$HADOOP_CLASSPATH test

This runs fine when I use SingleColumnValueFilter, but I get the above
error messages when I use my copy of that class. Maybe I am not running
this correctly?

Thanks,

Jon
On Wed, Oct 31, 2012 at 11:38 PM, Anoop John <[EMAIL PROTECTED]> wrote:

> You have one CF such that all rows will have KVs for that CF?
> You need to implement your own filter.
> Your scan can select the above CF and the on which u need the filtering.
> Have a look at the QualifierFilter.. similar approach you might need to do
> in the new filter..  Good luck :)
>
> -Anoop-
>
> On Thu, Nov 1, 2012 at 8:08 AM, anil gupta <[EMAIL PROTECTED]> wrote:
>
> > Hi Jonathan,
> >
> > Then in that case SingleColumnValueFilter will not work.
> > SingleColumnValueFilter works on the value of a cell rather than
> > ColumnQualifier name.
> > I have never heard of a built-in filter in HBase which can give you are
> all
> > rows  where a certain column family does not have any column qualifier.
> >
> > You can have a look at QualifierFilter:
> >
> >
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/filter/QualifierFilter.html
> > .
> > If QualifierFilter does suffices then you might have to implement by your
> > own.
> >
> > HTH,
> > Anil
> >
> > On Wed, Oct 31, 2012 at 4:07 PM, Jonathan Bishop <[EMAIL PROTECTED]
> > >wrote:
> >
> > > When I created the table I created column families, one of which is say
> > > "xyz".
> > >
> > > Now I would like to find all rows for which "xyz" is empty - in other
> > words
> > > no puts were made to that column family for that row.
> > >
> > > My column qualifiers are all "".
> > >
> > >
> > > On Wed, Oct 31, 2012 at 3:22 PM, anil gupta <[EMAIL PROTECTED]>
> > wrote:
> > >
> > > > Hi Jonathan,
> > > >
> > > > Do you mean that cell value is ""? or column qualifier is ""? I am
> > > confused
> > > > by your description.
> > > > If you were talking about cell value, at the time of put which object
> > do
> > > > you use for cell value? String?
> > > >
> > > > Thanks,
> > > > Anil
> > > >
> > > > On Wed, Oct 31, 2012 at 2:49 PM, Jonathan Bishop <
> > [EMAIL PROTECTED]
> > > > >wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I am trying to use SingleColumnValueFilter to find only those rows
> > > which
> > > > > have a particular column which is empty. Not sure what to use for
> the
> > > > value
> > > > > (4th arg in const). It does not take null, and I tried something
> > > like...
> > > > >
> > > > > byte[] v = new byte[0];
> > > > >
> > > > > but that does not seem to work.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Jon
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Thanks & Regards,
> > > > Anil Gupta
> > > >
> > >
> >
> >
> >
> > --
> > Thanks & Regards,
> > Anil Gupta
> >
>