Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase >> mail # user >> Hbase Count Aggregate Function


Copy link to this message
-
RE: Hbase Count Aggregate Function

Do you mean I implement a new rowCount method in Aggregation Client Class.

I cannot understand, could u illustrate with a code sample Ram?

Thanks,

> Date: Tue, 25 Dec 2012 00:21:14 +0530
> Subject: Re: Hbase Count Aggregate Function
> From: [EMAIL PROTECTED]
> To: [EMAIL PROTECTED]
>
> Hi
> You could have custom filter implemented which is similar to
> FirstKeyOnlyfilter.
> Implement the filterKeyValue method such that it should match your keyvalue
> (the specific qualifier that you are looking for).
>
> Deploy it in your cluster.  It should work.
>
> Regards
> Ram
>
> On Mon, Dec 24, 2012 at 10:35 PM, Dalia Sobhy <[EMAIL PROTECTED]>wrote:
>
> >
> > So do you have a suggestion how to enable/work the filter?
> >
> > > Date: Mon, 24 Dec 2012 22:22:49 +0530
> > > Subject: Re: Hbase Count Aggregate Function
> > > From: [EMAIL PROTECTED]
> > > To: [EMAIL PROTECTED]
> > >
> > > Okie, seeing the shell script and the code I feel that while you use this
> > > counter, the user's filter is not taken into account.
> > > It adds a FirstKeyOnlyFilter and proceeds with the scan. :(.
> > >
> > > Regards
> > > Ram
> > >
> > > On Mon, Dec 24, 2012 at 10:11 PM, Dalia Sobhy <
> > [EMAIL PROTECTED]>wrote:
> > >
> > > >
> > > > yeah scan gives the correct number of rows, while count returns the
> > total
> > > > number of rows.
> > > >
> > > > Both are using the same filter, I even tried it using Java API, using
> > row
> > > > count method.
> > > >
> > > > rowCount = aggregationClient.rowCount(TABLE_NAME, null, scan);
> > > >
> > > > I get the total number of rows not the number of rows filtered.
> > > >
> > > > So any idea ??
> > > >
> > > > Thanks Ram :)
> > > >
> > > > > Date: Mon, 24 Dec 2012 21:57:54 +0530
> > > > > Subject: Re: Hbase Count Aggregate Function
> > > > > From: [EMAIL PROTECTED]
> > > > > To: [EMAIL PROTECTED]
> > > > >
> > > > > So you find that scan with a filter and count with the same filter is
> > > > > giving you different results?
> > > > >
> > > > > Regards
> > > > > Ram
> > > > >
> > > > > On Mon, Dec 24, 2012 at 8:33 PM, Dalia Sobhy <
> > [EMAIL PROTECTED]
> > > > >wrote:
> > > > >
> > > > > >
> > > > > > Dear all,
> > > > > >
> > > > > > I have 50,000 row with diagnosis qualifier = "cardiac", and another
> > > > 50,000
> > > > > > rows with "renal".
> > > > > >
> > > > > > When I type this in Hbase shell,
> > > > > >
> > > > > > import org.apache.hadoop.hbase.filter.CompareFilter
> > > > > > import org.apache.hadoop.hbase.filter.SingleColumnValueFilter
> > > > > > import org.apache.hadoop.hbase.filter.SubstringComparator
> > > > > > import org.apache.hadoop.hbase.util.Bytes
> > > > > >
> > > > > > scan 'patient', { COLUMNS => "info:diagnosis", FILTER =>
> > > > > >     SingleColumnValueFilter.new(Bytes.toBytes('info'),
> > > > > >          Bytes.toBytes('diagnosis'),
> > > > > >          CompareFilter::CompareOp.valueOf('EQUAL'),
> > > > > >          SubstringComparator.new('cardiac'))}
> > > > > >
> > > > > > Output = 50,000 row
> > > > > >
> > > > > > import org.apache.hadoop.hbase.filter.CompareFilter
> > > > > > import org.apache.hadoop.hbase.filter.SingleColumnValueFilter
> > > > > > import org.apache.hadoop.hbase.filter.SubstringComparator
> > > > > > import org.apache.hadoop.hbase.util.Bytes
> > > > > >
> > > > > > count 'patient', { COLUMNS => "info:diagnosis", FILTER =>
> > > > > >     SingleColumnValueFilter.new(Bytes.toBytes('info'),
> > > > > >          Bytes.toBytes('diagnosis'),
> > > > > >          CompareFilter::CompareOp.valueOf('EQUAL'),
> > > > > >          SubstringComparator.new('cardiac'))}
> > > > > > Output = 100,000 row
> > > > > >
> > > > > > Even though I tried it using Hbase Java API, Aggregation Client
> > > > Instance,
> > > > > > and I enabled the Coprocessor aggregation for the table.
> > > > > > rowCount = aggregationClient.rowCount(TABLE_NAME, null, scan)
> > > > > >
> > > > > > Also when measuring the improved performance on case of adding more