The New Home of Oracle-wiki.net
All things oracle...
A website for IT Professionals involved with Oracle database.
Before discussing how to use the parallel hints, it is important to note, that these hints should be used sparingly, with caution and only when your system has enough IO and CPU resources to do so. It is exceptionally easy to bring a system to its knees using these hints. If you plan to use these hints, heed the warning and test before implementation. That said, lets take a look at how to use them.
The PARALLEL_INDEX hint is similar to the PARALLEL hint but is specifically used to parallelize index-related operations, such as creating or scanning indexes. While the PARALLEL hint applies to the entire query or DML operation (like select, insert, update, or delete), the PARALLEL_INDEX hint targets only index operations, typically improving performance for tasks like index range scans, full scans, fast full scans or index creation.
SELECT /*+ PARALLEL_INDEX(myTab1, myInd1, degree) */ col1
FROM myTab1
/
The NO_PARALLEL_INDEX hint explicitly disables parallel execution for a query, overriding any parallelism settings that may be configured at the system, session, or object level.
SELECT /*+ NO_PARALLEL_INDEX(myTab1, myInd1) */ col1
FROM myTab1
/
Notes
You can find more information on using parallel query in the documentation
Published on
Published 10th January 2025