I'll second Jack's detailed response and add that you really should do some discovery to figure out what kinds of queries you may need to support.
It might not be possible and often that is the case, but it's worth while to ask the end users what kind of reports they need to run. Allowing arbitrary ad-hoc queries is a known anti-pattern for cassandra. If the system needs to query multiple cf to derive/calculate some result, using Cassandra alone isn't going to do it. You'll need some other system to give you better query capabilities like Hive. If you need data warehouse like features, look at http://www.kylin.io/ . They are doing some interesting things. peter On Wed, Jun 10, 2015 at 7:58 AM, Jack Krupansky <jack.krupan...@gmail.com> wrote: > Knowing your queries in advance is a hard-core requirement for effective > deployment of Cassandra. Ad hoc queries are a very clear anti-pattern for > Cassandra. DSE Search does provide support for advanced, complex, and ad > hoc queries. Stratio and TupleJump Stargate can also be used. > > Back to the question of what you mean by ad hoc queries: > > 1. Do you expect real-time results, like sub-second, or are these > long-running queries that might take seconds, 10 seconds or more, or even > minutes to run? > 2. Will they be very rare or quite frequent - how much load do you expect > them to place on the cluster? > 3. How complex do you expect them to be - how many clauses and operators? > 4. What is their net cardinality - are they selecting just a few rows or > many rows? > 5. Do they have individual query clauses that select many rows even if the > net combination of all select clauses is not so many rows? > > The requirement to perform advanced, complex, and ad hoc queries using DSE > Search or the other techniques will almost certainly require that you use > moderately more capable hardware, especially more RAM, for each node, and > probably more nodes as well to reduce the row count per node since ad hoc > queries will tend to be compute-intensive based on number of rows on the > node. > > Yes, it can be done. No, it is not free or cheap. And, no, it does not > come out of the box for a non-DSE Cassandra release. And, yes, you must > address this requirement before deployment, not after deployment. > > > -- Jack Krupansky > > On Wed, Jun 10, 2015 at 1:18 AM, Srinivasa T N <seen...@gmail.com> wrote: > >> Thanks guys for the inputs. >> >> By ad-hoc queries I mean that I don't know the queries during cf design >> time. The data may be from single cf or multiple cf. (This feature maybe >> required if I want to do analysis on the data stored in cassandra, do you >> have any better ideas)? >> >> Regards, >> Seenu. >> >> On Tue, Jun 9, 2015 at 5:57 PM, Peter Lin <wool...@gmail.com> wrote: >> >>> >>> what do you mean by ad-hoc queries? >>> >>> Do you mean simple queries against a single column family aka table? >>> >>> Or do you mean MDX style queries that looks at multiple tables? >>> >>> if it's MDX style queries, many people extract data from Cassandra into >>> a data warehouse that support multi-dimensional cubes. This works well when >>> the extracted data is a small subset and fits neatly in a data warehouse. >>> >>> As others have stated, Cassandra isn't great at ad-hoc. For MDX style >>> queries, Cassandra wasn't designed for it. One thing we've done for our own >>> project is to combine solr with our own fuzzy index to make ad-hoc queries >>> against a single table more friendly. >>> >>> >>> >>> On Tue, Jun 9, 2015 at 2:38 AM, Srinivasa T N <seen...@gmail.com> wrote: >>> >>>> Hi All, >>>> I have an web application running with my backend data stored in >>>> cassandra. Now I want to do some analysis on the data stored which >>>> requires some ad-hoc queries fired on cassandra. How can I do the same? >>>> >>>> Regards, >>>> Seenu. >>>> >>> >>> >> >
