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From "Chandraprakash Sahu (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HBASE-10837) Filters failing to compare negative numbers (int,float,double or long)
Date Wed, 26 Mar 2014 08:39:14 GMT
Chandraprakash Sahu created HBASE-10837:
-------------------------------------------

             Summary: Filters failing to compare negative numbers (int,float,double or long)

                 Key: HBASE-10837
                 URL: https://issues.apache.org/jira/browse/HBASE-10837
             Project: HBase
          Issue Type: Improvement
          Components: Filters
    Affects Versions: 0.94.2
         Environment: Pseudo Mode
            Reporter: Chandraprakash Sahu
            Priority: Blocker


 I have come across an issue while using filters to get a result.

For eg.
I have created a table and its specifications are as follows :

table name --> test
column family --> cf
row keys --> rowKey1 - rowKey10 (10 different row keys)
column qualifier --> integerData

For different rowkeys, the qualifier 'integerData' contains either positive or negative integer
values (data loaded randomly).

Now, while I am trying to retrieve the data from the table based on a filter condition, its
failing to give the desired result.

For eg. say,
My table contains following data :
[-50,-40,-30,-20,-10,10,20,30,40,50]

I want to get only those values which are greater than or equal to 40.
Following is the code for the filter set on scan :

********************************************
  Scan scan = new Scan();
  scan.addColumn(Bytes.toBytes("cf"), Bytes.toBytes(" integerData"));
               
  int i = 40;
  Filter filter = new ValueFilter(CompareOp.GREATER_OR_EQUAL,new BinaryComparator(Bytes.toBytes(i)));

  scan.setFilter(filter);
*********************************************

The result should be : 40 and 50
BUT, the actual result is : -50, -40, -30, -20, -10, 40, 50

I have read few posts which addressed this issue, and few people provided the solution as:

1) write a custom comparator, as BinaryComparator is not meant for number comparison
OR
2) retrieve all the values as integer and then compare

BUT, I want to know if there is any other way to achieve this.
Because this seems to be a very basic need, i.e. comparing numbers, and I feel HBase should
have something straight forward to deal with this.
This comparison fails only when the negative numbers are involved.

I am not able to get the right way to do it.

My Hbase version is 0.94.2 and I am running it in pseudo mode.

Can anyone help me on this ? 



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