Managing Loader Jobs

Scenario

You can create, view, edit, and delete jobs on the Loader page.

This section applies to versions earlier than MRS 3.x.

Prerequisites

You have accessed the Loader page. For details, see Loader Page.

Creating a Job

1. On the Loader page, click New job.
2. In Connection, set parameters.
   1. In Name, enter a job name.
   2. In From link and To link, select links accordingly.

      After you select a link of a type, data is obtained from the specified source and saved to the destination.

      

      If no available link exists, click Add a new link.

3. In From, configure the job of the source link.

   For details, see Source Link Configurations of Loader Jobs.

4. In To, configure the job of the destination link.

   For details, see Destination Link Configurations of Loader Jobs.

5. Check whether a database link is selected in To link.

   Database links include:

   • generic-jdbc-connector
   • hbase-connector
   • hive-connector

   If you set To link to a database link, you need to configure a mapping between service data and a field in the database table.

   • If you set it to a database link, go to 6.
   • If you do not set it to a database link, go to 7.

6. In Field Mapping, enter a field mapping. Then proceed to 7.

   Field Mapping specifies a mapping between each column of user data and a field in the database table.

   Table 1 Field Mapping properties

   Parameter	Description
   Column Num	Field sequence of service data
   Sample	First row of sample values of service data
   Column Family	When To link is hbase-connector, you can select a column family for storing data.
   Destination Field	Field for storing data
   Type	Type of the field selected by the user
   Row Key	When To link is hbase-connector, you need to select Destination Field as a row key.

   

   If the value of From is a connector of a file type, for example, SFTP, FTP, OBS, and HDFS files, the value of Field Mapping is the first row of data in the file. Ensure that the first row of data is complete. Otherwise, the Loader job will not extract columns that are not mapped.

7. In Task Config, set job running parameters.

   Table 2 Loader job running properties

   Parameter	Description
   Extractors	Number of Map tasks
   Loaders	Number of Reduce tasks This parameter is displayed only when the destination field is HBase or Hive.
   Max. Error Records in a Single Shard	Error record threshold. If the number of error records of a single Map task exceeds the threshold, the task automatically stops and the obtained data is not returned. NOTE: Data is read and written in batches for MYSQL and MPPDB of generic-jdbc-connector by default. Errors are recorded once at most for each batch of data.
   Dirty Data Directory	Specifies the directory for saving dirty data. If you leave this parameter blank, dirty data will not be saved.

8. Click Save.

Viewing a Job

1. Access the Loader page. The Loader job management page is displayed by default.
   • If Kerberos authentication is enabled for the cluster, all jobs created by the current user are displayed by default and other users' jobs cannot be displayed.
   • If Kerberos authentication is disabled for the cluster, all Loader jobs of the cluster are displayed.

2. In Sqoop Jobs, enter a job name to filter the job.
3. Click Refresh to obtain the latest job status.

Editing a Job

1. Access the Loader page. The Loader job management page is displayed by default.
2. Click the job name to go to the edit page.
3. Modify the job configuration parameters based on service requirements.
4. Click Save.
   

   Basic job operations in the navigation bar on the left are Run, Copy, Delete, Disable, History Record, and Show Job JSON Definition.

Deleting a Job

1. Access the Loader page.
2. In the row of the specified job, click .

   You can also select one or more jobs and click Delete Job in the upper right corner of the job list.

3. In the dialog box, click Yes, delete it.

   If the state of a Loader job is Running, the job fails to be deleted.