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From Jonathan Gray <jl...@streamy.com>
Subject Re: Hi, i am still puzzeld to find a row key by a cell.
Date Mon, 17 Aug 2009 16:01:39 GMT
There is some built-in support for secondary indexes.

Look at IndexedTable.  It is in contrib for 0.20 and part of the main 
codebase for 0.19.

0.20 Javadoc:

http://jgray.la/javadoc/hbase-0.20.0/org/apache/hadoop/hbase/client/tableindexed/package-summary.html

0.19 Javadoc:

http://hadoop.apache.org/hbase/docs/r0.19.3/api/org/apache/hadoop/hbase/client/tableindexed/package-summary.html


There have been some performance issues in the past, but I've not used 
the built-in facilities for some time.  I do know of some people using 
this in production.  Internally, we implement some indexes in the same 
manner but manage it in the application.  See my previous e-mail to the 
list to understand how it's implemented.

JG

Ryan Rawson wrote:
> hey,
> 
> That isn't how hbase (or even rdbms) work.  Instead you can retrieve
> rows based on their row key. Otherwise you will have to read the
> entire table to find just that 1 row. Yes this is as inefficient as it
> sounds.
> 
> If you frequently have this issue, you may need to build and maintain
> secondary indexes. Unlike relational dbs, there is no built in support
> for this, you have to write your app to handle this.
> 
> -yran
> 
> 
> 
> On Sun, Aug 16, 2009 at 11:51 PM, lei wang<hbasemaillist@gmail.com> wrote:
>> Hi, if a know a cell in a hbase for its column:<qualifer>:value,  i need to
>> know which row key it belongs to. I searched the HBase api several times,
>> but i can not find the right method to solve my problem. Thanks for one's
>> suggestion to me.
>>
> 

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