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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: range queries
Date Wed, 27 Feb 2013 13:28:44 GMT
Things you can find searching on the web :

http://wiki.apache.org/cassandra/DataModel#Range_queries


2013/2/27 Alain RODRIGUEZ <arodrime@gmail.com>

> "What am I doing wrong here?"
>
> You are probably using a RandomPartitioner (or Murmur3Partitioner) which
> randomize keys to avoid hot spots.
>
> Basically, you just can't use range query because 'nlxxxxxxxxxx' is
> stored as md5('nlxxxxxxxxxx'). You should better modify your model to use
> column slice, which are ordered.
>
> An other solution, which is not recommended at all because it leads to hot
> spots, is to use an OrderedPreservingPartitioner. But once again, I think
> you shouldn't do it.
>
> I have no time to go deeper in my explanation but with what I already told
> you, you should be able to find out by yourself more details if needed.
>
> Alain
>
>
> 2013/2/27 Sloot, Hans-Peter <hans-peter.sloot@atos.net>
>
> Hello,
>>
>> I have what is perhaps a silly question.
>>
>> Column family other2 which has a varchar as primary key and a uuid column.
>> I  have inserted 2000 rows
>>
>> All rows keys start with 'nl' followed by other characters.
>>
>> To my surprise when I do  : select count(*) from other2 where key > 'z';
>>
>> It shows :
>>
>>  count
>> -------
>>   1947
>>
>> All rows start with a character smaller than 1.
>>
>> But it becomes even more strange:
>>
>> cqlsh:demo> select count(*) from other2 where key > 'zz';
>>  count
>> -------
>>   1415
>>
>> cqlsh:demo> select count(*) from other2 where key > 'zzz';
>>  count
>> -------
>>   1820  < -- now the row count has even increased.
>>
>> What am I doing wrong here?
>>
>> Regards
>>
>>
>>
>>
>>
>>
>>
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