Dear all,
I wanted to ask a question..
Do Hbase Aggregate Functions such as rowcount, getMax, get Average use MapReduce to execute those functions?
Thanks :D    

Regards, Dalia.
You have to use MapReduce for that.
In the HBase in Practiceï؟½s book, there are lot of great examples for this.

On 11/24/2012 12:15 PM, Dalia Sobhy wrote:
> Dear all,
> I wanted to ask a question..
> Do Hbase Aggregate Functions such as rowcount, getMax, get Average use MapReduce to execute those functions?
> Thanks :D  
>
--

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Hi, but you do not need to us M/R. You could also use coprocessors.

See this site:
https://blogs.apache.org/hbase/entry/coprocessor_introduction
-> in the section "Endpoints"

An aggregation coprocessor ships with hbase that should match your
requirements.
You just need to load it and eventually you can access it from HTable:

HTable.coprocessorExec(..)
<http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#coprocessorExec%28java.lang.Class,%20byte[],%20byte[],%20org.apache.hadoop.hbase.client.coprocessor.Batch.Call,%20org.apache.hadoop.hbase.client.coprocessor.Batch.Callback%29>

Regards
tom

Am 24.11.2012 18:32, schrieb Marcos Ortiz:
> Regards, Dalia.
> You have to use MapReduce for that.
> In the HBase in Practiceï؟½s book, there are lot of great examples for
> this.
>
> On 11/24/2012 12:15 PM, Dalia Sobhy wrote:
>> Dear all,
>> I wanted to ask a question..
>> Do Hbase Aggregate Functions such as rowcount, getMax, get Average
>> use MapReduce to execute those functions?
>> Thanks :D
>>
>
>

Do you think it would be a good idea to temper the use of CoProcessors?

This kind of reminds me of when people first started using stored procedures...
Sent from a remote device. Please excuse any typos...

Mike Segel

On Nov 24, 2012, at 11:46 AM, tom <[EMAIL PROTECTED]> wrote:

> Hi, but you do not need to us M/R. You could also use coprocessors.
>
> See this site:
> https://blogs.apache.org/hbase/entry/coprocessor_introduction
> -> in the section "Endpoints"
>
> An aggregation coprocessor ships with hbase that should match your requirements.
> You just need to load it and eventually you can access it from HTable:
>
> HTable.coprocessorExec(..) <http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#coprocessorExec%28java.lang.Class,%20byte[],%20byte[],%20org.apache.hadoop.hbase.client.coprocessor.Batch.Call,%20org.apache.hadoop.hbase.client.coprocessor.Batch.Callback%29>
>
> Regards
> tom
>
> Am 24.11.2012 18:32, schrieb Marcos Ortiz:
>> Regards, Dalia.
>> You have to use MapReduce for that.
>> In the HBase in Practice´s book, there are lot of great examples for this.
>>
>> On 11/24/2012 12:15 PM, Dalia Sobhy wrote:
>>> Dear all,
>>> I wanted to ask a question..
>>> Do Hbase Aggregate Functions such as rowcount, getMax, get Average use MapReduce to execute those functions?
>>> Thanks :D
>

It 's weird that hbase aggregate functions don't use MapReduce, this means that the performance will be very poor.
Is it a must to use coprocessors?
Is there a much easier way to improve the functions' performance ?

> CC: [EMAIL PROTECTED]
> From: [EMAIL PROTECTED]
> Subject: Re: Hbase MapReduce
> Date: Sat, 24 Nov 2012 12:05:45 -0600
> To: [EMAIL PROTECTED]
>
> Do you think it would be a good idea to temper the use of CoProcessors?
>
> This kind of reminds me of when people first started using stored procedures...
>
>
> Sent from a remote device. Please excuse any typos...
>
> Mike Segel
>
> On Nov 24, 2012, at 11:46 AM, tom <[EMAIL PROTECTED]> wrote:
>
> > Hi, but you do not need to us M/R. You could also use coprocessors.
> >
> > See this site:
> > https://blogs.apache.org/hbase/entry/coprocessor_introduction
> > -> in the section "Endpoints"
> >
> > An aggregation coprocessor ships with hbase that should match your requirements.
> > You just need to load it and eventually you can access it from HTable:
> >
> > HTable.coprocessorExec(..) <http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#coprocessorExec%28java.lang.Class,%20byte[],%20byte[],%20org.apache.hadoop.hbase.client.coprocessor.Batch.Call,%20org.apache.hadoop.hbase.client.coprocessor.Batch.Callback%29>
> >
> > Regards
> > tom
> >
> > Am 24.11.2012 18:32, schrieb Marcos Ortiz:
> >> Regards, Dalia.
> >> You have to use MapReduce for that.
> >> In the HBase in Practiceï؟½s book, there are lot of great examples for this.
> >>
> >> On 11/24/2012 12:15 PM, Dalia Sobhy wrote:
> >>> Dear all,
> >>> I wanted to ask a question..
> >>> Do Hbase Aggregate Functions such as rowcount, getMax, get Average use MapReduce to execute those functions?
> >>> Thanks :D
> >
     

Actually coprocessor can be used to implement MR-like function, while not
using Hadoop framework.

Best Regards,
Wei

Wei Tan
Research Staff Member
IBM T. J. Watson Research Center
Yorktown Heights, NY 10598
[EMAIL PROTECTED]; 914-784-6752

From:   Dalia Sobhy <[EMAIL PROTECTED]>
To:     "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>,
Date:   11/24/2012 01:33 PM
Subject:        RE: Hbase MapReduce
It 's weird that hbase aggregate functions don't use MapReduce, this means
that the performance will be very poor.
Is it a must to use coprocessors?
Is there a much easier way to improve the functions' performance ?

> CC: [EMAIL PROTECTED]
> From: [EMAIL PROTECTED]
> Subject: Re: Hbase MapReduce
> Date: Sat, 24 Nov 2012 12:05:45 -0600
> To: [EMAIL PROTECTED]
>
> Do you think it would be a good idea to temper the use of CoProcessors?
>
> This kind of reminds me of when people first started using stored
procedures...
>
>
> Sent from a remote device. Please excuse any typos...
>
> Mike Segel
>
> On Nov 24, 2012, at 11:46 AM, tom <[EMAIL PROTECTED]> wrote:
>
> > Hi, but you do not need to us M/R. You could also use coprocessors.
> >
> > See this site:
> > https://blogs.apache.org/hbase/entry/coprocessor_introduction
> > -> in the section "Endpoints"
> >
> > An aggregation coprocessor ships with hbase that should match your
requirements.
> > You just need to load it and eventually you can access it from HTable:
> >
> > HTable.coprocessorExec(..) <
http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/HTable.html#coprocessorExec%28java.lang.Class,%20byte
[],%20byte[],%20org.apache.hadoop.hbase.client.coprocessor.Batch.Call,%20org.apache.hadoop.hbase.client.coprocessor.Batch.Callback%29>
> >
> > Regards
> > tom
> >
> > Am 24.11.2012 18:32, schrieb Marcos Ortiz:
> >> Regards, Dalia.
> >> You have to use MapReduce for that.
> >> In the HBase in Practice´s book, there are lot of great examples for
this.
> >>
> >> On 11/24/2012 12:15 PM, Dalia Sobhy wrote:
> >>> Dear all,
> >>> I wanted to ask a question..
> >>> Do Hbase Aggregate Functions such as rowcount, getMax, get Average
use MapReduce to execute those functions?
> >>> Thanks :D
> >
  

Hello:

I'm working in a proyect, and i'm using hbase for storage the data, y have this method that work great but without the performance i'm looking for, so i want is to make the same but using mapreduce.
public ArrayList<MyObject> findZ(String z) throws IOException {

        ArrayList<MyObject> rows = new ArrayList<MyObject>();
        Configuration conf = HBaseConfiguration.create();
        HTable table = new HTable(conf, "test");
        Scan s = new Scan();
        s.addColumn(Bytes.toBytes("x"), Bytes.toBytes("y"));
        ResultScanner scanner = table.getScanner(s);
        try {
            for (Result rr : scanner) {
                if (Bytes.toString(rr.getValue(Bytes.toBytes("x"), Bytes.toBytes("y"))).equals(z)) {
                    rows.add(getInformation(Bytes.toString(rr.getRow())));
                }
            }
        } finally {
            scanner.close();
        }
        return archivos;
    }

the getInformation method take all the columns and convert the row in MyObject type.

I just want a example or a link to a tutorial that make something like this,  i want to get a result type as answer and not a number to count words, like many a found.
My natural language is spanish, so sorry if something is not well writing.

Thanths
http://www.uci.cu