Hi Aaron, Thank you for your answer, I was beginning to think that my question would never be answered ;-)
Actually, this is what I was going for, except one thing, instead of partitioning row per month, I though about partitioning per day, like that everyday I launch the cleaning tool, and it will delete the day from X month earlier. I guess that will reduce the workload drastically, does it have any downside comparing to month partitioning? At one point I was going to do something like the twissandra example, Having a CF per User's queue, and another CF per day storing every message's ID of the day, in that way If I want to delete them, I only look into this row, and delete them using ID's for deleting them in the User's queue CF… Is that a good way to do ? Or should I stick with the first implementation ? Best regards, Morgan. Le 30 avr. 2012 à 05:52, aaron morton a écrit : > Message Queue is often not a great use case for Cassandra. For information on > how to handle high delete workloads see > http://www.datastax.com/dev/blog/leveled-compaction-in-apache-cassandra > > It hard to create a model without some idea of the data load, but I would > suggest you start with: > > CF: UserMessages > Key: ReceiverID > Columns : column name = TimeUUID ; column value = message ID and Body > > That will order the messages by time. > > Depending on load (and to support deleting a previous months messages) you > may want to partition the rows by month: > > CF: UserMessagesMonth > Key: ReceiverID+YYYYMM > Columns : column name = TimeUUID ; column value = message ID and Body > > Everything the same as before. But now a user has a row for each month and > which you can delete as a whole. This also helps avoid very big rows. > >> I really don't think that storage will be an issue, I have 2TB per nodes, >> messages are 1KB limited. > I would suggest you keep the per node limit to 300 to 400 GB. It can take a > long time to compact, repair and move the data when it gets above 400GB. > > Hope that helps. > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 27/04/2012, at 1:30 AM, Morgan Segalis wrote: > >> Hi everyone ! >> >> I'm fairly new to cassandra and I'm not quite yet familiarized with column >> oriented NoSQL model. >> I have worked a while on it, but I can't seems to find the best model for >> what I'm looking for. >> >> I have a Erlang software that let user connecting and communicate with each >> others, when an user (A) sends >> a message to a disconnected user (B), it stores it on the database and wait >> for the user (B) to connect and retrieve >> the message queue, and deletes it. >> >> Here's some key point : >> - Users are identified by integer IDs >> - Each message are unique by combination of : Sender ID - Receiver ID - >> Message ID - time >> >> I have a queue Message, and here's the operations I would need to do as fast >> as possible : >> >> - Store from 1 to X messages per registered user >> - Get the number of stored messages per user (Can be a incremental variable >> updated at each store // this is often retrieved) >> - retrieve all messages from an user at once. >> - delete all messages from an user at once. >> - delete all messages that are older than Y months (from all users). >> >> I really don't think that storage will be an issue, I have 2TB per nodes, >> messages are 1KB limited. >> I'm really looking for speed rather than storage optimization. >> >> My configuration is 2 dedicated server which are both : >> - 4 x Intel i7 2.66 Ghz >> - 64 bits >> - 24 Go >> - 2 TB >> >> Thank you all. >
