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.
- Prepare for application migration.
- 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.
- Educate your users about the new DB2 Text
Search syntax and semantic rules.
- Prepare for index migration.
- Start DB2 Text Search.
- 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.
- 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.
- Schedule DB2 Text Search
incremental index updates to ensure synchronization with base table
updates.
- 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.
- Ensure the DB2 Text Search
indexes are working successfully.
- If successful, backup and then delete the Net Search Extender
indexes. Finally, disable the Net Search Extender database.
- If you encounter problems, switch the application
and index activation back to Net Search Extender until the issue is
fixed.
DB2 Version 10.1 for Linux, UNIX, and Windows