incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Or Yanay ...@peer39.com>
Subject RE: newbie question: how do I know the total number of rows of a cf?
Date Mon, 28 Mar 2011 13:16:34 GMT
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

Mime
View raw message