Sorry, I forget why. Someone told me at the cassandra conference. It might be to not overload the entire cluster at once so if you have 1000 nodes and you run just 5 queries, you could take out your cluster. (This is why I use playorm's querying and in tons of use cases, you don't want to query the entire clusterŠ.usually that is saved for a map/reduce type operation).
Dean On 8/21/13 9:10 AM, "Kanwar Sangha" <kan...@mavenir.com> wrote: >Thanks Dean. Any reason why it is sequential ? It is to avoid loading all >the nodes and see if one node can return the desired results ? > > >-----Original Message----- >From: Hiller, Dean [mailto:dean.hil...@nrel.gov] >Sent: 21 August 2013 07:36 >To: user@cassandra.apache.org >Subject: Re: Secondary Index Question > >Yup, there are other types of indexing like that in PlayOrm which do it >differently so all nodes are not hit so it works better for instance if >you are partitioning your data and you query into just a single partition >so it doesn't put load on all the nodes. (of course, you have to have a >partition strategy to partition by say month with key being the timestamp >of begin of month or maybe you partition by account as you only query >into accounts). > >It is feasible to roll your own as well. (though you do need to worry >about eventual consistency here when rolling your own) > >Later, >Dean > >From: Kanwar Sangha <kan...@mavenir.com<mailto:kan...@mavenir.com>> >Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" ><user@cassandra.apache.org<mailto:user@cassandra.apache.org>> >Date: Tuesday, August 20, 2013 6:57 PM >To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" ><user@cassandra.apache.org<mailto:user@cassandra.apache.org>> >Subject: Secondary Index Question > >Hi - I was reading some blogs on implementation of secondary indexes in >Cassandra and they say that "the read requests are sent sequentially to >all the nodes" ? > >So if I have a query to fetch ALL records with the secondary index >filter, will the co-ordinator node send the requests to nodes one by one ? > >Thanks, >Kanwar >
