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Posted to user@cassandra.apache.org by Shay Assulin <SH...@il.ibm.com> on 2011/02/13 15:48:47 UTC

Secondary index - keys only.

HI,

Is there a way to get only the keys of indexed rows (without getting 
columns) using get_indexed_slices method?

I am using Hector to access Cassandra and I want to count rows with a 
specific index - so i need to get only the keys.

I am doing the following:


n = 0

while (true) {

        indexedSliceQuery.setStartKey(    lastFetchedKey  )   
        indexedSliceQuery.setReturnedKeysOnly();
        indexedSliceQuery.addFilter(  the indexed column EQ value  )

        res = indexedSliceQuery.execute();
        n += res.size();
        update lastFetchedKey
        if (size == 0) break;
} 

It looks like the time it takes to get keys are just like the time it 
takes to get the entire row.

Re: Secondary index - keys only.

Posted by Jonathan Ellis <jb...@gmail.com>.

No.

On Sun, Feb 13, 2011 at 8:48 AM, Shay Assulin <SH...@il.ibm.com> wrote:
> HI,
>
> Is there a way to get only the keys of indexed rows (without getting
> columns) using get_indexed_slices method?
>
> I am using Hector to access Cassandra and I want to count rows with a
> specific index - so i need to get only the keys.
>
> I am doing the following:
>
>
> n = 0
>
> while (true) {
>
>         indexedSliceQuery.setStartKey(    lastFetchedKey  )
>
>         indexedSliceQuery.setReturnedKeysOnly();
>         indexedSliceQuery.addFilter(  the indexed column EQ value  )
>
>         res = indexedSliceQuery.execute();
>         n += res.size();
>         update lastFetchedKey
>         if (size == 0) break;
> }
>
> It looks like the time it takes to get keys are just like the time it takes
> to get the entire row.
>
>
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com