@Sudharsan Ganeshkumar The optimal number of mappers depends on many variables: you need to take into account your database type, the hardware that is used for your database server, and the impact to other requests that your database needs to serve. There is no optimal number of mappers that works for all scenarios. Instead, you’re encouraged to experiment to find the optimal degree of parallelism for your environment and use case. It’s a good idea to start with a small number of mappers, slowly ramping up, rather than to start with a large number of mappers, working your way down. When you run sqoop import with -m 1 option, 1 mapper will be launched and in case this parameter is specified, sqoop will run 4 mappers by default. ... View more

@Sudharsan Ganeshkumar Snapshots are stored in the same path under .snapshot directory. for example, If you take snapshot of /user/root, it would be stored in /user/root/.snapshot directory. An example is given below. [hdfs@sandbox ~]$ hdfs dfsadmin -allowSnapshot /user/root/testsnap snapsAllowing snaphot on /user/root/testsnaps succeeded [root@sandbox ~]# hdfs dfs -createSnapshot /user/root/testsnaps snap1 Created snapshot /user/root/testsnaps/.snapshot/snap1 [gulshad@sandbox ~]$ hdfs dfs -createSnapshot /user/gulshad Created snapshot /user/gulshad/.snapshot/s20180831-145829.441 To get all Snapshotable directories, run below command. [root@sandbox ~]# sudo -su hdfs hdfs lsSnapshottableDir drwxr-xr-x 0 root hdfs 0 2018-07-26 05:29 3 65536 /user/root/testsnaps drwxr-xr-x 0 hdfs hdfs 0 2018-08-01 14:58 1 65536 /proj/testsnap drwxr-xr-x 0 gulshad hdfs 0 2018-08-01 14:58 1 65536 /user/gulshad ... View more

@Sudharsan Ganeshkumar If the above has helped, please take a moment to login and click the "accept" link on the answer. ... View more

@Sudharsan Ganeshkumar You are not seeing anything because you are running the command as root user ! You will have to switch to the hive user and use hive or beeline # su - hive $ hive Then at the prompt run the create statement hive> CREATE TABLE IF NOT EXISTS emp ( eid int, name String, salary String, destination String) COMMENT ‘Employee details’ ROW FORMAT DELIMITED FIELDS TERMINATED BY ‘\t’ LINES TERMINATED BY ‘\n’ STORED AS TEXTFILE; And then run hive> show table emp; HTH ... View more

@Sudharsan Ganeshkumar if my answer has helped you please remember to login and mark it as accepted. ... View more