Not if you want to sort by score (a counter) Am 14.01.2017 08:33 schrieb "DuyHai Doan" <doanduy...@gmail.com>:
> Clustering column can be seen as sorted set > > Table abstraction == Map<PartitionKey , SortedMap<Clustering Column, ...>> > > > On Sat, Jan 14, 2017 at 2:28 AM, Edward Capriolo <edlinuxg...@gmail.com> > wrote: > >> >> >> On Fri, Jan 13, 2017 at 8:14 PM, Jonathan Haddad <j...@jonhaddad.com> >> wrote: >> >>> I've thought about this for years and have never arrived on a >>> particularly great implementation. Your idea will be maybe OK if the sets >>> are very small and if the values don't change very often. But in a system >>> where the values of the keys in the set change frequently (lots of >>> tombstones) or the sets are large I think you're going to experience quite >>> a bit of pain. >>> >>> On Fri, Jan 13, 2017 at 2:14 PM Mike Torra <mto...@demandware.com> >>> wrote: >>> >>> We currently use redis to store sorted sets that we increment many, many >>> times more than we read. For example, only about 5% of these sets are ever >>> read. We are getting to the point where redis is becoming difficult to >>> scale (currently at >20 nodes). >>> >>> We've started using cassandra for other things, and now we are >>> experimenting to see if having a similar 'sorted set' data structure is >>> feasible in cassandra. My approach so far is: >>> >>> 1. Use a counter CF to store the values I want to sort by >>> 2. Periodically read in all key/values in the counter CF and sort in >>> the client application (~every five minutes or so) >>> 3. Write back to a different CF with the ordered keys I care about >>> >>> Does this seem crazy? Is there a simpler way to do this in cassandra? >>> >>> >> Redis is the other side of the coin. >> >> Fast: >> https://groups.google.com/forum/#!topic/redis-db/4TAItKMyUEE >> >> http://stackoverflow.com/questions/6076342/is-there-a-practi >> cal-limit-to-the-number-of-elements-in-a-sorted-set-in-redis >> >> 320MB memory for a 2,000,000 email addresses is hard to scale. If you are >> only maintaining a single list great, but if you have millions of lists >> this memory/ cost profile is not idea. >> > >
