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From Michal Augustýn <>
Subject Re: get_indexed_slices ~ simple map-reduce
Date Sun, 12 Jun 2011 20:34:15 GMT

as I wrote, I don't want to install Hadoop etc. - I want just to use
the Thrift API. The core of my question is how does get_indexed_slices
function work.

I know that it must get all keys using equality expression firstly -
but what about additional expressions? Does Cassandra fetch whole
filtered rows, or just columns used in additional filtering



2011/6/12 aaron morton <>:
> Not exactly sure what you mean here, all data access is through the thrift
> API unless you code java and embed cassandra in your app.
> As well as Pig support there is also Hive support in brisk (which will also
> have Pig support soon)
> Can you provide some more info on the use case ? Personally if you have a
> read query you know you need to support, I would consider supporting it in
> the data model without secondary indexes.
> Cheers
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> On 11 Jun 2011, at 19:23, Michal Augustýn wrote:
> Hi all,
> I'm thinking of get_indexed_slices function as a simple map-reduce job
> (that just maps) - am I right?
> Well, I would like to be able to run simple queries on values but I
> don't want to install Hadoop, write map-reduce jobs in Java (the whole
> application is in C# and I don't want to introduce new development
> stack - maybe Pig would help) and have some second interface to
> Cassandra (in addition to Thrift). So secondary indexes seem to be
> rescue for me. I would have just one indexed column that will have
> day-timestamp value (~100k items per day) and the equality expression
> for this column would be in each query (and I would add more ad-hoc
> expressions).
> Will this scenario work or is there some issue I could run in?
> Thanks!
> Augi

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