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From David Boxenhorn <da...@lookin2.com>
Subject Re: Range search on keys not working?
Date Wed, 02 Jun 2010 12:48:59 GMT
That's crazy! I could artificially insert a key with just the prefix, as a
placeholder, but why can't Cassandra do that virtually?

On Wed, Jun 2, 2010 at 3:34 PM, Dr. Martin Grabm├╝ller <
Martin.Grabmueller@eleven.de> wrote:

>  I think you can specify an end key, but it should be a key which does
> exist in your column family.
>
> But maybe I'm off the track here and someone else here knows more about
> this key range stuff.
>
> Martin
>
>  ------------------------------
> *From:* David Boxenhorn [mailto:david@lookin2.com]
> *Sent:* Wednesday, June 02, 2010 2:30 PM
>
> *To:* user@cassandra.apache.org
> *Subject:* Re: Range search on keys not working?
>
>  In other words, I should check the values as I iterate, and stop
> iterating when I get out of range?
>
> I'll try that!
>
> On Wed, Jun 2, 2010 at 3:15 PM, Dr. Martin Grabm├╝ller <
> Martin.Grabmueller@eleven.de> wrote:
>
>>  When not using OOP, you should not use something like 'CATEGORY/' as the
>> end key.
>> Use the empty string as the end key and limit the number of returned keys,
>> as you did with
>> the 'max' value.
>>
>> If I understand correctly, the end key is used to generate an end token by
>> hashing it, and
>> there is not the same correspondence between 'CATEGORY' and 'CATEGORY/' as
>> for
>> hash('CATEGORY') and hash('CATEGORY/').
>>
>> At least, this was the explanation I gave myself when I had the same
>> problem.
>>
>> The solution is to iterate through the keys by always using the last key
>> returned as the
>> start key for the next call to get_range_slices, and the to drop the first
>> element from
>> the result.
>>
>> HTH,
>>   Martin
>>
>>  ------------------------------
>> *From:* David Boxenhorn [mailto:david@lookin2.com]
>> *Sent:* Wednesday, June 02, 2010 2:01 PM
>> *To:* user@cassandra.apache.org
>> *Subject:* Re: Range search on keys not working?
>>
>>   The previous thread where we discussed this is called, "key is sorted?"
>>
>>
>>
>> On Wed, Jun 2, 2010 at 2:56 PM, David Boxenhorn <david@lookin2.com>wrote:
>>
>>> I'm not using OPP. But I was assured on earlier threads (I asked several
>>> times to be sure) that it would work as stated below: the results would not
>>> be ordered, but they would be correct.
>>>
>>> On Wed, Jun 2, 2010 at 2:51 PM, Torsten Curdt <tcurdt@vafer.org> wrote:
>>>
>>>> Sounds like you are not using an order preserving partitioner?
>>>>
>>>> On Wed, Jun 2, 2010 at 13:48, David Boxenhorn <david@lookin2.com>
>>>> wrote:
>>>> > Range search on keys is not working for me. I was assured in earlier
>>>> threads
>>>> > that range search would work, but the results would not be ordered.
>>>> >
>>>> > I'm trying to get all the rows that start with "CATEGORY."
>>>> >
>>>> > I'm doing:
>>>> >
>>>> > String start = "CATEGORY.";
>>>> > .
>>>> > .
>>>> > .
>>>> > keyspace.getSuperRangeSlice(columnParent, slicePredicate, start,
>>>> > "CATEGORY/", max)
>>>> > .
>>>> > .
>>>> > .
>>>> >
>>>> > in a loop, setting start to the last key each time - but I'm getting
>>>> rows
>>>> > that don't start with "CATEGORY."!!
>>>> >
>>>> > How do I get all rows that start with "CATEGORY."?
>>>>
>>>
>>>
>>
>

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