Sqoop In Depth
In earlier post we have seen need of Sqqop ? what are the Sqoop commands ? And what are the file formats Sqoop supports. Now lets dive in into the functional aspect of Sqoop like How does Sqoop imports/exports data from/to RDBMS.. Sqoop Import Sqoop’s import tool will run a MapReduce job that connects to the MySQL database and reads the table. By default, this will use four map tasks in parallel.Each task will write its imported results to a different file.If a distributed Hadoop cluster is being used, localhost (in jdbc:mysql://localhost/dbname )should not be specified in the connect string, because map tasks not running on the same machine as the database will fail to connect. For example we have 3 nodes (machines) in a cluster with ip 192.168.0.1, 192.168.0.2, 192.168.0.3 (consider these ip addresses just for example purpose). Lets assume MySql is installed on machine 192.168.0.2 .After running sqoop import with connection string as " jdbc:mysql://localhost/dbname