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From Victor Kabdebon <>
Subject Re: online chat scenario
Date Tue, 15 Feb 2011 13:56:47 GMT
Hello Sasha.

In this sort of real time application the way you insert (QUORUM, ONE,
etc..) and  the way you retrieve is extremely important because your data
may not have had the time to propagate to all your nodes. Be sure to use
adequate policies to do that : insert to a certain number of nodes but don't
sacrifice to much time doing that to keep the real time component.
Here is a presentation of how the chat is made in Facebook, it may be useful
to you :

It's more focused on erlang, but it might give you ideas on how to deal with
that problem (I am not sure that DB are the best way to deal with that...
but it's just my opinion).

Victor Kabdebon

2011/2/15 Sasha Dolgy <>

> thanks for the response.  thinking about this, this would not allow for the
> sorting of messages into a chronological order for end user display.  i had
> thought about having each message as its own column against the room or the
> user, but i have had some inconsistencies in retrieving the data.  sometimes
> i get 3 columns, sometimes i get 50...( i think this is because of the
> random partitioner)
> i had thought about this structure:
> [messages][nickname][message id => message data]
> [chatrooms][room_name][message id]
> this way i can pull all messages a user ever posted, not specific to a
> room.  what i haven't been able to do so far is print the timestamp on the
> row or column.  does this have to be explicitly added somewhere or can it be
> returned as part of a 'get' request?
> -sd
> On Tue, Feb 15, 2011 at 2:12 PM, Michal August├Żn <
>> wrote:
>> The schema design depends on chatrooms/users/messages numbers. I.e. you
>> can have one CF, where key is chatroom, column name is username, column
>> value is the message and message time is the same as column timestamp.
>> You can add day-timestamp to the chatroom name to avoid large rows.
>> Augi
>> 2011/2/15 Andrey V. Panov <>
>> I never did it. But I suppose you can use "chatroom name" as key and store
>>> messages & nicks as columns in JSON and timestamp as columnName.
> --
> Sasha Dolgy

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