Thanks all. 2011/3/28 Stephen Connolly <stephen.alan.conno...@gmail.com>
> for #2 you could pipe through wc -l to get the answer > > sort -n keys.txt | uniq | wc -l > > but both examples are just refinements of iterate. > > #1 is just a distributed iterate > #2 is just an optimized iterate based on knowledge of the on-disk > format (and my give inaccurate results... tombstones...) > > On 28 March 2011 14:16, Or Yanay <o...@peer39.com> wrote: > > I use one of two ways to achieve that: > > 1. run a map reduce. Pig is really helpful in these cases. Make sure you > run your MR using Hadoop task tracker on your nodes - or your performance > will take a hit. > > 2. dump all keys using sstablekeys script from relevant files on all > machines and count unique values. I do that using "sort -n keys.txt |uniq > >> unique_keys.txt" > > > > Dumping all keys is much faster but less elegant and can be more annoying > if you want do that from your application. > > > > Hope that do the trick for you. > > -Orr > > > > -----Original Message----- > > From: Joshua Partogi [mailto:joshua.j...@gmail.com] > > Sent: Monday, March 28, 2011 2:39 PM > > To: user@cassandra.apache.org > > Subject: Re: newbie question: how do I know the total number of rows of a > cf? > > > > Not all NoSQL is like that. Or perhaps the term NoSQL has became vague > > these days. > > > > On Mon, Mar 28, 2011 at 6:16 PM, Stephen Connolly > > <stephen.alan.conno...@gmail.com> wrote: > >> iterate. > >> > >> otherwise if that will be too slow and you will do it often, the nosql > way > >> is to create a separate column family updated with each row add/delete > to > >> hold the answer for you. > >> > >> - Stephen > >> > >> --- > >> Sent from my Android phone, so random spelling mistakes, random nonsense > >> words and other nonsense are a direct result of using swype to type on > the > >> screen > >> > >> On 28 Mar 2011 07:40, "Sheng Chen" <chensheng2...@gmail.com> wrote: > >>> Hi all, > >>> I want to know how many records I am holding in Cassandra, just like > >>> count(*) in sql. > >>> What can I do ? Thank you. > >>> > >>> Sheng > >> > > > > > > > > -- > > http://twitter.com/jpartogi > > >
