ERROR tool.ImportTool: Error during import: No primary key could be found for table

12/03/05 23:44:31 ERROR tool.ImportTool: Error during import: No primary key could be found for table Employee_Table. Please specify one with --split-by or perform a sequential import with '-m 1'.

Sample queryon which i got this error

$ sqoop-import --connect jdbc:mysql://localhost:3306/sqoop --username root --password root --table Employee_Table --target-dir employeeImportAll

Explanation

While performing the parallel imports Sqoop needs a criterion by which it can split the workload.Sqoop uses the splitting column to split the workload. By default Sqoop will identify the primary key column (if present) in a table to use as the splitting column.

The low and high values of splitting column are retrieved from databases and the map tasks operate on evenly sized components of total range.

For example , if you had a table with a primary key column of id whose minimum value was 0 and maximum value was 1000, and Sqoop was directed to use 4 tasks, Sqoop would run four processes which each execute SQL statements of the form SELECT * FROM sometable WHERE id >= lo AND id < hi, with (lo, hi) set to (0, 250), (250, 500), (500, 750), and (750, 1001) in the different tasks.

Solution

$ sqoop-import --connect jdbc:mysql://localhost:3306/sqoop --username root --password root --table Employee_Table --target-dir employeeImportAll --m 1

Just add the --m 1 , it tells to use sequential import with 1 mapper

Or another solution can be by telling to sqoop to use particulay column as split column.

$ sqoop-import --connect jdbc:mysql://localhost:3306/sqoop --username root --password root --table Employee_Table --target-dir employeeImportAll  --split-by columnName