Parallel Indexing

Oracle Text supports parallel indexing with CREATE INDEX.

When you enter a parallel indexing statement on a non-partitioned table, Oracle Text splits the base table into temporary partitions, spawns child processes, and assigns a child to a partition. Each child then indexes the rows in its partition. The method of slicing the base table into partitions is determined by Oracle and is not under your direct control. This is true as well for the number of child processes actually spawned, which depends on machine capabilities, system load, your init.ora settings, and other factors. Because of these variables, the actual parallel degree may not match the degree of parallelism requested.

Because indexing is an I/O intensive operation, parallel indexing is most effective in decreasing your indexing time when you have distributed disk access and multiple CPUs. Parallel indexing can only affect the performance of an initial index with CREATE INDEX. It does not affect DML performance with ALTER INDEX, and has minimal impact on query performance.

Because parallel indexing decreases the initial indexing time, it is useful for the following scenarios:

• Data staging, when your product includes an Oracle Text index

• Rapid initial startup of applications based on large data collections

• Application testing, when you need to test different index parameters and schemas while developing your application

  See Also:

  • "Parallel Queries on a Local Context Index"

  • "Frequently Asked Questions About Indexing Performance"