Migration overview from Net Search Extender to Db2 Text Search

Db2 Text Search provides sophisticated linguistic processing support for full-text search and improved capabilities for search in XML documents.

Before you port from Net Search Extender to Db2 Text Search, consider the following important aspects:
  • Db2 Text Search and Net Search Extender comparison

    Review the topic about Db2 Text Search and Net Search Extender feature comparisons to check for your migration readiness. If you are using only supported text search features, you should start preparing for migration to Db2 Text Search.

  • Application migration

    Db2 Text Search and Net Search Extender differ both syntactically and semantically. It is necessary to modify your applications accordingly.

  • Text index migration

    The two text search engines differ in their formats, so it is not possible to reuse existing Net Search Extender indexes for searches with Db2 Text Search. Text indexes must be rebuilt.

  • Security model

    The Db2 Text Search security model has been enhanced. Three new system roles are available which allow operations to be conducted with the authorization ID of the user to improve auditability and management.

  • Text search solution planning

    Understanding certain solution planning concepts, such as supported document format and data types, will help you leverage the benefits of Db2 Text Search. Furthermore, a number of factors influence performance and resource use in Db2 Text Search. When planning system capacity for Db2 Text Search, consider the number of index updates, the expected size and growth rates of your text search indexes, and the processing time for the documents you are indexing.

Refer to the following instructions for an overview of the migration steps.
  1. Prepare for application migration.
    1. Check the text index activation status to generate proper syntax on-the-fly according to the text index type in use. Alternatively, create a revised application version with the new syntax.
    2. Educate your users about the new Db2 Text Search syntax and semantic rules.
  2. Prepare for index migration.
    1. Start Db2 Text Search.
    2. Enable the Net Search Extender database for Db2 Text Search. Issue a db2ts ENABLE DATABASE FOR TEXT command or the corresponding stored procedure operation for the database.
    3. Create and update inactive Db2 Text Search indexes on columns with active Net Search Extender indexes. Issue a db2ts CREATE INDEX FOR TEXT command, or its corresponding stored procedure, on the same table and column for which the Net Search Extender text index exists already. You will now have both Net Search Extender and Db2 Text Search indexes within the database.
    4. Schedule Db2 Text Search incremental index updates to ensure synchronization with base table updates.
  3. 3. When text indexes are ready, switch the application version and activate the new Db2 Text Search index using the ALTER INDEX command with the SET ACTIVE option enabled.
  4. Ensure the Db2 Text Search indexes are working successfully.
    1. If successful, backup and then delete the Net Search Extender indexes. Finally, disable the Net Search Extender database.
    2. If you encounter problems, switch the application and index activation back to Net Search Extender until the issue is fixed.