Help Center> MapReduce Service> Developer Guide (2.x and Earlier)> HBase Application Development> Application Development> Deleting a Secondary Index
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Deleting 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 deleting all indexes from a table.

Based on whether the user wants to delete index data and indexes, this class provide two APIs to delete indexes.

  • dropIndices()
  • dropIndicesWithData()

Sample Code

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

dropIndices (): Delete the specified index from the specified table, excluding index data.

  public void dropIndicesExample() {
    LOG.info("Entering Deleting 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);
      // Drop the specified indices without dropping index data
      iAdmin.dropIndices(tableName, indexNameList);
      // Alternately, drop the specified indices with data
      // iAdmin.dropIndicesWithData(tableName, indexNameList);
      LOG.info("Successfully dropped indices " + indexNameList + " from the table " + tableName);
    } catch (IOException e) {
      LOG.error("Failed to drop indices " + indexNameList + " from 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 Deleting a Hindex.");
  }

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

dropIndicesWithData (): Delete a specified index from a specified table, including all related index data, from the user table.

   public void dropIndicesExampleWithData() {
    LOG.info("Entering Deleting a Hindex With Data.");
    List<String> indexNameList = new ArrayList<String>();
    indexNameList.add(indexNameToAdd);
    Admin admin = null;
    HIndexAdmin iAdmin = null;
    try {
      admin = conn.getAdmin();
      iAdmin = HIndexClient.newHIndexAdmin(admin);
      // Drop the specified indices without dropping index data
      iAdmin.dropIndicesWithData(tableName, indexNameList);
      // Alternately, drop the specified indices with data
      // iAdmin.dropIndicesWithData(tableName, indexNameList);
      LOG.info("Successfully dropped indices " + indexNameList + " from the table " + tableName);
    } catch (IOException e) {
      LOG.error("Failed to drop indices " + indexNameList + " from 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 Deleting a Hindex With Data.");
  }
Parent topic: Application Development