Hi guys,
In MYSQL I have a table departments_null_nonnull which has 9 rows and last is null for both department_id and department_name.
I ran the following command :
sqoop import
–connect jdbc:mysql://sandbox.hortonworks.com:3306/retail_db \
–username retail_dba
—-password hadoop
—-table departments_null_nonnull
—-hive-import
—-hive-home /apps/hive/warehouse
—-hive-table sqoop_import_hive.departments_null_nonnull
—-create-hive-table
-m -4
—-null-string nvl
—-null-non-string -1
—-split-by department_id
In hive prompt when I did select * from departments_null_nonnull I did not see nvl and -1. In sqoop import too it said fetching 8 records.
But in the above command when I changed -m from 4 to 1 and then executing select * from departments_null_nonnull in hive I was able to see the expected result both -1 and nvl.
I did not understand the importance of changing -m from 4 to 1.
Can anybody explain me.
Thanks in Advance 