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From Sheng Chen <chensheng2...@gmail.com>
Subject Re: newbie question: how do I know the total number of rows of a cf?
Date Tue, 29 Mar 2011 08:17:55 GMT
Thanks all.

2011/3/28 Stephen Connolly <stephen.alan.connolly@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 <or@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.java@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.connolly@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" <chensheng2010@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
> >
>

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