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From Todd Burruss <bburr...@expedia.com>
Subject Re: Second Cassandra users survey
Date Wed, 09 Nov 2011 06:55:33 GMT
A use case that could use this (but isn't in my top requests) is usage
history for a given user.  I use a single row to save history per user,
each column is a user action with name a TimeUUID and value is a blob.  I
use the TimeUUID to sort the actions, but I don't really care about exact
time.  after the number of user actions exceeds a threshold, I want to
remove enough to bring the actions back below the threshold.  I could
model this as you say and remove chunks of actions by deleting a row, but
that is more cumbersome for the client.

The reason this isn't in my top requests is regardless if the client or
the server performs this sort of delete, the row must first be read.  By
having the server do it, a network hop is saved as well as implementing a
common usage pattern.

On 11/5/11 2:45 PM, "Brandon Williams" <driftx@gmail.com> wrote:

>On Fri, Nov 4, 2011 at 9:50 PM, Jim Newsham <jnewsham@referentia.com>
>wrote:
>> Our use case is time-series data (such as sampled sensor data).  Each
>>row
>> describes a particular statistic over time, the column name is a time,
>>and
>> the column value is the sample.  So it makes perfect sense to want to
>>delete
>> columns for a given time range.  I'm sure there must be numerous other
>>use
>> cases for which using a range of column names makes sense.
>
>Assuming you are bucketing your rows at some interval (as in
>http://rubyscale.com/2011/basic-time-series-with-cassandra/), why is
>deleting the entire row for the interval not acceptable?
>
>-Brandon


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