Hi all, I've red all your messages concerning the top 10 ... any solution is possibile but I still did not find the best one.
Using a composite Column Name as suggested would be smart cause it brings to a sorted row where I can have my top-10 in any moment but it can slow down all the platform since, for every operation, I have to read data from cassandra, calculate and store data back. Using counters I could just say "hey, +1 on this" and forget. But using counters I don't have any kind of value-sorting ... I know redis but I think it's too much to use a new key-value db just for this sorting ... I think I'll use a thread that run every X to generate the top10 row ... it won't be realtime but at least it will keep platform performance to a good level. Thank you all and merry christmas >----Messaggio originale---- >Da: ben...@noisette.ch >Data: 25/12/2011 10.19 >A: <user@cassandra.apache.org> >Ogg: Re: Counters and Top 10 > >With Composite Column Name, you can even have column composed of sore >(int) and userid (uuid or whatever). Empty column value to avoid >repeating user UUID. > > >2011/12/22 R. Verlangen <ro...@us2.nl>: >> I would suggest you to create a CF with a single row (or multiple for >> historical data) with a date as key (utf8, e.g. 2011-12-22) and multiple >> columns for every user's score. The column (utf8) would then be the score + >> something unique of the user (e.g. hex representation of the TimeUUID). The >> value would be the TimeUUID of the user. >> >> By default columns will be sorted and you can perform a slice to get the top >> 10. >> >> 2011/12/14 cbert...@libero.it <cbert...@libero.it> >> >>> Hi all, >>> I'm using Cassandra in production for a small social network (~10.000 >>> people). >>> Now I have to assign some "credits" to each user operation (login, write >>> post >>> and so on) and then beeing capable of providing in each moment the top 10 >>> of >>> the most active users. I'm on Cassandra 0.7.6 I'd like to migrate to a new >>> version in order to use Counters for the user points but ... what about >>> the top >>> 10? >>> I was thinking about a specific ROW that always keeps the 10 most active >>> users >>> ... but I think it would be heavy (to write and to handle in thread-safe >>> mode) >>> ... can counters provide something like a "value ordered list"? >>> >>> Thanks for any help. >>> Best regards, >>> >>> Carlo >>> >>> >> > > > >-- >sent from my Nokia 3210 >
