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From aaron morton <aa...@thelastpickle.com>
Subject Re: How to find total number of rows in Cassandra databaase?
Date Wed, 24 Apr 2013 03:22:50 GMT
cassandra-cli has some good online help.

There are no features to count rows as cassandra does not count them, but it it's only 1,000
try using list;

You can also see the number of rows by using nodetool cfstats. 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Consultant
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 23/04/2013, at 6:50 PM, Techy Teck <comptechgeeky@gmail.com> wrote:

> Is there any way to see how many rows are there using CLI mode? If I don't want to use
CQL mode.
> 
> 
> On Mon, Apr 22, 2013 at 12:13 AM, Nikolay Mihaylov <nmmm@nmmm.nu> wrote:
> Hi
> 
> it is very important to know that counting rows is very very very expensive.
> here is my 5 cents - 
> 
> in one of my early projects we made separate column family, with just single row.
> we inserted each row key from other CF on this row as column key.
> 
> then once a day or who, we did get_count().
> 
> however because get_count() became way too slow,
> we have split the keys on several rows - e.g. on 1024 rows.
> it is still way too slow, but we do not need it to be realtime.
> 
> in our "second" project we decided to use cassandra counters.
> however in order to be distinct, we need to read before write.
> this degrade insert performance, so we did special CF with hashesh and other stuff.
> insert performance is still slow. 2 sec or something for 500-600 counters
> (note single insert is OK, but we need to do 500-600 per batch, and 100-200 batches per
second).
> 
> finally we have researched about probabilistic counters and we decided to use these.
> we also decided to make the project in Python, and we did not do proper tests yes.
> 
> this is our final "take", it uses modified hyper log log, so we do not need to read at
all.
> 
> https://github.com/nmmmnu/CubicHyperLogLog
> 
> we tested the library very well, but not with real live data.
> version for Redis is included too for easy testing.
> 
> Nikolay.
> 
> 
> 
> 
> 
> On Mon, Apr 22, 2013 at 2:19 AM, Utkarsh Sengar <utkarsh2012@gmail.com> wrote:
> Difference b/w cqlsh and cli is documented by the datastax guys here nicely: http://www.datastax.com/support-forums/topic/cli-vs-cql
> 
> Thanks,
> -Utkarsh
> 
> 
> On Sun, Apr 21, 2013 at 1:39 PM, Techy Teck <comptechgeeky@gmail.com> wrote:
> Yeah it helps a lot. I always have this doubt with me. What is the difference between
CLI and CQL?
> 
> 
> 
> On Sun, Apr 21, 2013 at 1:30 PM, Utkarsh Sengar <utkarsh2012@gmail.com> wrote:
> Using cqlsh you can do:
> 
> SELECT COUNT(*) FROM columnfamily LIMIT 5000;
> 
> Does that help?
> 
> Read more: http://www.datastax.com/docs/1.0/references/cql/SELECT
> 
> Thanks,
> -Utkarsh
> 
> 
> 
> On Sun, Apr 21, 2013 at 1:04 PM, Techy Teck <comptechgeeky@gmail.com> wrote:
> I have inserted 1000 rows in Cassandra database. Now I am trying to find out how many
rows have been inserted in Cassandra database using the CLI mode.
> 
> 
> In rdbms, I can do this sql-
> 
>        SELECT count(*) from TABLE;
> 
> And this will give me total count for that table;
> 
> How to do the same thing in Cassandra database?
> 
> I am running Cassandra 1.2.3
> 
> 
> 
> -- 
> Thanks,
> -Utkarsh
> 
> 
> 
> 
> -- 
> Thanks,
> -Utkarsh
> 
> 


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