Range of values
1 to 255
LOG_PARALLELISM specifies the level of concurrency for redo allocation within Oracle.
If you are using Oracle on high-end servers that have more than 16 processors, and you are experiencing very high contention on the redo allocation latch, then you should consider enabling parallel redo. This allows the parallel generation of redo and can increase the throughput of certain update-intensive workloads. You can examine the V$LATCH view to observe the cumulative wait times on the redo allocation latch.
To enable parallel redo, set the LOG_PARALLELISM parameter in the initialization parameter file to the desired level of concurrency for redo allocation. Oracle Corporation recommends setting LOG_PARALLELISM to a value between 2 and 8 when running on systems with 16 to 64 processors. You can start with a low value (such as 2) and increment it by 1 until you determine that the redo allocation latch is no longer contended, and that the parameter improves the performance of the application.
Setting LOG_PARALLELISM to values greater than 8 is not currently recommended.
来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/9078678/viewspace-45101/，如需转载，请注明出处，否则将追究法律责任。