> Is there a good blog/article that describes how using MapReduce on Cassandra > table ? The best way to get into cassandra and hadoop is to play with Cassandra DSE.
It’s free for development, costs for production, and is an easy way to learn about hadoop integration without having to worry about the installation process. http://www.datastax.com/docs/datastax_enterprise3.1/solutions/about_hadoop > If a database table is input source for MapReduce or Storm, for me , this is > in the simple case, is translating to a full table scan of the input table, > which can timeout and is generally not a recommended access pattern in > Cassandra. The Hadoop integration is token aware, it splits the tasks to run local on the node. The tasks then scan over the token range local to the node. Hope that helps. A ----------------- Aaron Morton New Zealand @aaronmorton Co-Founder & Principal Consultant Apache Cassandra Consulting http://www.thelastpickle.com On 9/05/2014, at 9:43 am, Manoj Khangaonkar <khangaon...@gmail.com> wrote: > Hi, > > Searching for Cassandra with MapReduce, I am finding that the search results > are really dated -- from version 0.7 & 2010/2011. > > Is there a good blog/article that describes how using MapReduce on Cassandra > table ? > > From my naive understanding, Cassandra is all about partitioning. Querying is > based on partitionkey + clustered column(s). > > Inputs to MapReduce is a sequence of Key,values. For Storm it is a stream of > tuples. > > If a database table is input source for MapReduce or Storm, for me , this is > in the simple case, is translating to a full table scan of the input table, > which can timeout and is generally not a recommended access pattern in > Cassandra. > > My initial reaction is that if I need to process data with MapReduce or > Storm, reading it from Cassandra might not be the optimal way. Storing the > output to Cassandra however does make sense. > > If anyone had links to blogs or personal experience in this area, I would > appreciate if you can share it. > > regards > > >
