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From Jonathan Shook <jsh...@gmail.com>
Subject Re: list of columns
Date Mon, 17 May 2010 01:31:21 GMT
I think you are correct, David. What Bill is asking for specifically
is not in the API.

Bill,
if this is a performance concern (i.e., your column values are/could
be vastly larger than your column names, and you need to query the
namespace before loading the values), then you might consider keeping
a separate column family which just contains the column names and
timestamps with empty values.

On Sun, May 16, 2010 at 4:37 AM, David Boxenhorn <david@lookin2.com> wrote:
> Bill, I am a new user of Cassandra, so I've been following this discussion
> with interest. I think the answer is "no", except for the brute force method
> of looping through all your data. It's like asking for a list of all the
> files on your C: drive. The term "column" is very misleading, since
> "columns" are really leaves of a tree structure, not columns of a tabular
> structure.
>
> Anybody want to tell me I'm wrong?
>
> BTW, Bill, I think we've corresponded before, here:
> http://www.dehora.net/journal/2004/04/whats_in_a_name.html
>
> On Fri, May 14, 2010 at 2:23 AM, Bill de hOra <bill@dehora.net> wrote:
>>
>> A SlicePredicate/SliceRange can't exclude column values afaik.
>>
>> Bill
>>
>> Jonathan Shook wrote:
>>>
>>> get_slice
>>>
>>> see: http://wiki.apache.org/cassandra/API under get_slice and
>>> SlicePredicate
>>>
>>> On Thu, May 13, 2010 at 9:45 AM, Bill de hOra <bill@dehora.net> wrote:
>>>>
>>>> get_count returns the number of columns, not the names of those columns?
>>>> I
>>>> should have been specific, by "list the columns", I meant "list the
>>>> column
>>>> names".
>>>>
>>>> Bill
>>>>
>>>> Gary Dusbabek wrote:
>>>>>
>>>>> We have get_count at the thrift level.  You supply a predicate and it
>>>>> returns the number of columns that match.  There is also
>>>>> multi_get_count, which is the same operation against multiple keys.
>>>>>
>>>>> Gary.
>>>>>
>>>>>
>>>>> On Thu, May 13, 2010 at 04:18, Bill de hOra <bill@dehora.net> wrote:
>>>>>>
>>>>>> Admin question - is there a way to list the columns for a particular
>>>>>> key?
>>>>>>
>>>>>> Bill
>>>>>>
>>>>
>>
>
>

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