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From Stack <st...@duboce.net>
Subject Re: habse schema design and retrieving values through REST interface
Date Wed, 16 Mar 2011 17:47:44 GMT
You can limit the return when scanning from the java api; see
http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/Scan.html#setBatch(int)
 This facility is not exposed in the REST API at the moment (not that
I know of -- please someone correct me if I'm wrong).   So, yes, wide
rows, if thousands of elements of some size, since they need to be
composed all in RAM, could bring on an OOME if the composed size >
available heap.

St.Ack


On Wed, Mar 16, 2011 at 2:41 AM, sreejith P. K. <sreejithpk@nesote.com> wrote:
> With this schema, if i can limit the column family over a particular range,
> I can manage everything else. (like Select first n columns of a column
> family)
>
> Sreejith
>
>
> On Wed, Mar 16, 2011 at 12:33 PM, sreejith P. K. <sreejithpk@nesote.com>wrote:
>
>> @ Jean-Daniel,
>>
>> As i told, each row key contains thousands of column family values (may be
>> i am wrong with the schema design). I started REST and tried to cURL
>> http:/localhost/tablename/rowname. It seems it will work only with limited
>> amount of data (may be i can limit the cURL output), and how i can limit the
>> column values for a particular row?
>> Suppose i have two thousand urls under a keyword and i need to fetch the
>> urls and should limit the result to five hundred. How it is possible??
>>
>> @ tsuna,
>>
>>  It seems http://www.elasticsearch.org/ using CouchDB right?
>>
>>
>> On Tue, Mar 15, 2011 at 11:32 PM, Jean-Daniel Cryans <jdcryans@apache.org>wrote:
>>
>>> Can you tell why it's not able to get the bigger rows? Why would you
>>> try another schema if you don't even know what's going on right now?
>>> If you have the same issue with the new schema, you're back to square
>>> one right?
>>>
>>> Looking at the logs should give you some hints.
>>>
>>> J-D
>>>
>>> On Tue, Mar 15, 2011 at 10:19 AM, sreejith P. K. <sreejithpk@nesote.com>
>>> wrote:
>>> > Hello experts,
>>> >
>>> > I have a scenario as follows,
>>> > I need to maintain a huge table for a 'web crawler' project in HBASE.
>>> > Basically it contains thousands of keywords and for each keyword i need
>>> to
>>> > maintain a list of urls (it again will count in thousands).
>>> Corresponding to
>>> > each url, i need to store a number, which will in turn resemble the
>>> priority
>>> > value the keyword holds.
>>> > Let me explain you a bit, Suppose i have a keyword 'united states', i
>>> need
>>> > to store about ten thousand urls corresponding to that keyword. Each
>>> keyword
>>> > will be holding a priority value which is an integer. Again i have
>>> thousands
>>> > of keywords like that. The rare thing about this is i need to do the
>>> project
>>> > in PHP.
>>> >
>>> > I have configured a hadoop-hbase cluster consists of three machines. My
>>> plan
>>> > was to design the schema by taking the keyword as 'row key'. The urls i
>>> will
>>> > keep as column family. The schema looked fine at first. I have done a
>>> lot of
>>> > research on how to retrieve the url list if i know the keyword. Any ways
>>> i
>>> > managed a way out by preg-matching the xml data out put using the url
>>> > http://localhost:8080/tablename/rowkey (REST interface i used). It also
>>> > works fine if the url list has a limited number of urls. When it comes
>>> in
>>> > thousands, it seems i cannot fetch the xml data itself!
>>> > Now I am in a do or die situation. Please correct me if my schema design
>>> > needs any changes (I do believe it should change!) and please help me up
>>> to
>>> > retrieve the column family values (urls)
>>> >  corresponding to each row-key in an efficient way. Please guide me how
>>> i
>>> > can do the same using PHP-REST interface.
>>> > Thanks in advance.
>>> >
>>> > Sreejith
>>> >
>>>
>>
>>
>>
>> --
>> Sreejith PK
>> Nesote Technologies (P) Ltd
>>
>>
>>
>
>
> --
> Sreejith PK
> Nesote Technologies (P) Ltd
>

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