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From chovatia jaydeep <chovatia_jayd...@yahoo.co.in>
Subject Re: When does it make sense to use TimeUUID?
Date Wed, 15 Jun 2011 19:00:56 GMT
Hi Sameer,

One example is, store all the tweets for a given user in a Column 
Family, where row key is user name/user id and column name is of 
TimeUUID type that  represents tweet arrival time. User would generally 
like to see the tweets sorted based on its arrival time. So TimeUUID 
will help here.

Thank you,
Jaydeep


________________________________
From: Sameer Farooqui <cassandralabs@gmail.com>
To: user@cassandra.apache.org
Sent: Tuesday, 14 June 2011 5:16 PM
Subject: When does it make sense to use TimeUUID?


I would like to store some timestamped user info in a Column Family with the usernames as
the row key and different timestamps as column names. Each user might have a thousand timestamped
data.

I understand that the ver 1 UUIDs that Cassandra combines the MAC address of the computer
generating the UUID with the number of 100-nanosecond intervals since the beginning of the
Gregorian calendar.

So, if user1 had data stored for an event at Jan 30, 2011/2:15pm and user2 had an event at
the exact same time, the data could potentially be stored in different column names? So, I
would have to know the MAC of the generating computer in order to do a column slice, right? 

When does it make sense to use TimeUUID vs just a time string like 20110130141500 and comparator
type UTF8?

- Sameer
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