Defines the number of map tasks that the Sqoop program must use to import and export data in parallel.
Use the following syntax:
--num-mappers <number of map tasks>
For example, to use 8 map tasks, configure the num-mappers argument as follows:
If you configure the num-mappers argument, you must also configure the split-by argument to specify the column based on which the Sqoop program must split the work units. If you do not configure the split-by argument, the value of the num-mappers argument defaults to 1.
Use the num-mappers argument to increase the degree of parallelism. You might have to test different values for optimal performance.