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From "B. Todd Burruss" <bto...@gmail.com>
Subject Re: Option for ordering columns by timestamp in CF
Date Fri, 12 Oct 2012 21:39:54 GMT
trying to think of a use case where you would want to order by
timestamp, and also have unique column names for direct access.

not really trying to challenge the use case, but you can get ordering
by timestamp and still maintain a "name" for the column using
composites. if the first component of the composite is a timestamp,
then you can order on it.  when retrieved you will could have a "name"
in the second component .. and have dupes as long as the timestamp is
unique (use TimeUUID)


On Fri, Oct 12, 2012 at 7:20 AM, Derek Williams <derek@fyrie.net> wrote:
> You probably already know this but I'm pretty sure it wouldn't be a trivial
> change, since to efficiently lookup a column by name requires the columns to
> be ordered by name. A separate index would be needed in order to provide
> lookup by column name if the row was sorted by timestamp (which is the way
> Redis implements it's sorted set).
>
>
> On Fri, Oct 12, 2012 at 12:13 AM, Ertio Lew <ertiop93@gmail.com> wrote:
>>
>> "Make column timestamps optional"- kidding me, right ?:)  I do understand
>> that this wont be possible as then cassandra wont be able to distinguish the
>> latest among several copies of same column. I dont mean that. I just want
>> the while ordering the columns, Cassandra(in an optional mode per CF) should
>> not look at column names(they will exist though but for retrieval purposes
>> not for ordering) but instead Cassandra would order the columns by looking
>> at the timestamp values(timestamps would exist!). So the change would be
>> just to provide a mode in which cassandra, while ordering, uses timestamps
>> instead of column names.
>>
>>
>> On Fri, Oct 12, 2012 at 2:26 AM, Tyler Hobbs <tyler@datastax.com> wrote:
>>>
>>> Without thinking too deeply about it, this is basically equivalent to
>>> disabling timestamps for a column family and using timestamps for column
>>> names, though in a very indirect (and potentially confusing) manner.  So, if
>>> you want to open a ticket, I would suggest framing it as "make column
>>> timestamps optional".
>>>
>>>
>>> On Wed, Oct 10, 2012 at 4:44 AM, Ertio Lew <ertiop93@gmail.com> wrote:
>>>>
>>>> I think Cassandra should provide an configurable option on per column
>>>> family basis to do columns sorting by time-stamp rather than column names.
>>>> This would be really helpful to maintain time-sorted columns without using
>>>> up the column name as time-stamps which might otherwise be used to store
>>>> most relevant column names useful for retrievals. Very frequently we need
to
>>>> store data sorted in time order. Therefore I think this may be a very
>>>> general requirement & not specific to just my use-case alone.
>>>>
>>>> Does it makes sense to create an issue for this ?
>>>>
>>>>
>>>>
>>>>
>>>> On Fri, Mar 25, 2011 at 2:38 AM, aaron morton <aaron@thelastpickle.com>
>>>> wrote:
>>>>>
>>>>> If you mean order by the column timestamp (as passed by the client)
>>>>> that it not possible.
>>>>>
>>>>> Can you use your own timestamps as the column name and store them as
>>>>> long values ?
>>>>>
>>>>> Aaron
>>>>>
>>>>> On 25 Mar 2011, at 09:30, Narendra Sharma wrote:
>>>>>
>>>>> > Cassandra 0.7.4
>>>>> > Column names in my CF are of type byte[] but I want to order columns
>>>>> > by timestamp. What is the best way to achieve this? Does it make
sense for
>>>>> > Cassandra to support ordering of columns by timestamp as option
for a column
>>>>> > family irrespective of the column name type?
>>>>> >
>>>>> > Thanks,
>>>>> > Naren
>>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> Tyler Hobbs
>>> DataStax
>>>
>>
>
>
>
> --
> Derek Williams
>

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