• MapReduce Service

mrs
  1. Help Center
  2. MapReduce Service
  3. User Guide
  4. Using MRS
  5. Using Loader
  6. Managing Loader Jobs

Managing Loader Jobs

Scenario

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

Prerequisites

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

Create a Job

  1. On the Loader page, click New job.
  2. In Information, 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.

      NOTE:

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

  6. In Field Mapping, enter a field mapping. Perform Step 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 line 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.

    NOTE:

    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 appears only when the destination field is HBase or Hive.

    Max error records in single split

    Error record threshold. If error records of a single map task exceed 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

    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 in 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 in the cluster, all Loader jobs of the cluster are displayed.

  2. In Sqoop Jobs, enter a job name or link type 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.

    NOTE:

    Basic job operations in the navigation bar on the left are RunCopyDeleteDisableHistory Record, and Show Job JSON Definition.

Deleting a Job

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

    Alternatively, you can select one or more jobs and click Delete jobs 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.