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From Techy Teck <comptechge...@gmail.com>
Subject Re: How to find total number of rows in Cassandra databaase?
Date Tue, 23 Apr 2013 06:50:37 GMT
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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