All Products
Search

This Product

    E-MapReduce:Switch the metadata storage type

    Document Center

    E-MapReduce:Switch the metadata storage type

    Last Updated:Apr 17, 2026

    In Alibaba Cloud E-MapReduce (EMR), you can select a metadata storage type, such as Data Lake Formation (DLF) or ApsaraDB RDS, when you create a cluster. You can also change the metadata storage type after a cluster is created. This topic introduces Data Lake Formation and describes how to switch the metadata storage type for an EMR cluster.

    Background information

    DLF is a fully managed service that is developed by Alibaba Cloud to help you easily build and manage a cloud-native data lake. DLF allows you to manage metadata and user permissions in a centralized manner, ingest data into data lakes with ease, and explore data in data lakes with a few clicks. For more information, see Overview.

    DLF also allows you to connect the cloud-native data lake to various compute engines. This way, you can break down data silos and gain insight into the business value of data.

    Prerequisites

    The DLF service is activated in the DLF console.

    Limitations

    • DLF unified metadata storage is compatible with Hive 2.x, Hive 3.x, Presto, and Spark SQL in EMR.

    • Only EMR 3.30.0 or later and EMR 4.5.0 or later support DLF unified metadata storage as a Hive database.

    Procedure

    1. Go to the Hive service page.

      1. Log on to the E-MapReduce console.

      2. In the top navigation bar, select a region and a resource group based on your business requirements.

      3. On the EMR on ECS page, find the target cluster and click Services in the Actions column.

      4. In the Hive service section, click Configure.

    2. In the configuration search box, enter the parameter name hive.imetastoreclient.factory.class and click the search icon.

      • To switch to a MySQL metastore (including built-in MySQL, unified metadatabase, and self-managed RDS):

        Set hive.imetastoreclient.factory.class to org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClientFactory.

      • To switch to DLF unified metadata storage:

        Set hive.imetastoreclient.factory.class to com.aliyun.datalake.metastore.hive2.DlfMetaStoreClientFactory.

    3. Save the configuration.

      1. In the Service Configuration section of the Hive service page, click Save.

      2. In the dialog box that appears, enter an execution reason and click Save.

    4. Restart the Hive service.

      1. On the Hive service page, choose More > restart in the upper-right corner.

      2. In the dialog box that appears, enter an Execution Reason and click OK.

      3. In the Confirm dialog box, click OK.

        You can click Operation History at the top of the page to view the task progress and wait for the task to complete.