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Enabling/Disabling a Secondary Index

Prerequisites

This function is available only in MRS 1.7 or later version.

Function Description

You can use the methods provided by org.apache.hadoop.hbase.hindex.client.HIndexAdmin to manage HIndexes. This class provides methods of enabling/disabling an existing index.

The HIndexAdmin provides the following APIs based on whether you want to enable or disable a table.

  • disableIndices ()
  • enableIndices ()

Sample Code

The following code snippets are in the enableIndicesExample method in the HIndexExample class of the com.huawei.bigdata.hbase.examples packet.

enableIndices (): Enable a specified index (the index status changes from INACTIVE to ACTIVE). This API can also be used to scan indexes.

  public void enableIndicesExample() {
    LOG.info("Entering Enabling a Hindex.");
    List<String> indexNameList = new ArrayList<String>();
    indexNameList.add(indexNameToAdd);
    Admin admin = null;
    HIndexAdmin iAdmin = null;
    try {
      admin = conn.getAdmin();
      iAdmin = HIndexClient.newHIndexAdmin(admin);
      // Disable the specified indices
      iAdmin.enableIndices(tableName, indexNameList);
      // Alternately, disable the specified indices
      // iAdmin.disableIndices(tableName, indexNameList)
      LOG.info("Successfully enable indices " + indexNameList + " of the table " + tableName);
    } catch (IOException e) {
      LOG.error("Failed to enable indices " + indexNameList + " of the table " + tableName);
    } finally {
      if (iAdmin != null) {
        try {
          // Close the HIndexAdmin object.
          iAdmin.close();
        } catch (IOException e) {
          LOG.error("Failed to close HIndexAdmin ", e);
        }
      }
      if (admin != null) {
        try {
          // Close the Admin object.
          admin.close();
        } catch (IOException e) {
          LOG.error("Failed to close admin ", e);
        }
      }
    }
    LOG.info("Exiting Enabling a Hindex.");
  }

The following code snippets are in the disableIndicesExample method in the HIndexExample class of the com.huawei.bigdata.hbase.examples packet.

disableIndices (): Disable a specified index (the index status changes from ACTIVE to INACTIVE). Therefore, index scanning becomes unavailable.

  public void disableIndicesExample() {
    LOG.info("Entering Disabling a Hindex.");
    List<String> indexNameList = new ArrayList<~>();
    indexNameList.add(indexNameToAdd);
    Admin admin = null;
    HIndexAdmin iAdmin = null;
    try {
      admin = conn.getAdmin();
      iAdmin = HIndexClient.newHIndexAdmin(admin);
      // Disable the specified indices
      iAdmin.disableIndices(tableName, indexNameList);
      // Alternately, enable the specified indices
      // iAdmin.enableIndices(tableName, indexNameList);
      LOG.info("Successfully disabled indices " + indexNameList + " of the table " + tableName);
    } catch (IOException e) {
      LOG.error("Failed to disable indices " + indexNameList + " of the table " + tableName);
    } finally {
      if (iAdmin != null) {
        try {
          // Close the HIndexAdmin object.
          iAdmin.close();
        } catch (IOException e) {
          LOG.error("Failed to close HIndexAdmin ", e);
        }
      }
      if (admin != null) {
        try {
          // Close the Admin object.
          admin.close();
        } catch (IOException e) {
          LOG.error("Failed to close admin ", e);
        }
      }
    }
    LOG.info("Exiting Disabling a Hindex.");
  }
Parent topic: Application Development