The "default" DOP is cpu_count * parallel_threads_per_cpu, however if the execution plan has both producer/consumer slave sets, it will use 2 * DOP parallel execution servers. For example, with cpu_count=12 and parallel_threads_per_cpu=2, the default DOP would be 12 * 2 = 24, however the query could use 48 parallel execution servers depending on the execution plan. On Thu, Mar 4, 2010 at 8:13 AM, girlgeek <girlgeek@xxxxxxxx> wrote: > Ric, > Thank you for the explanation. I had always wondered about something that I > saw at a prior shop. Someone had used a parallel hint without degree and > managed to get 57 parallel processes running, (mostly fighting) on a 12 cpu > box. If the table was defined as parallel without a degree, the > documentation says that Oracle defines that the degree of parallelism to use > is the number of cpu times the value in the init parameter > parallel_threads_per_cpu. I didn't check at the time, but I assume that they > must have set the init parameter parallel_threads_per_cpu to 4. There are a > few extra processes not explained by that logic, but I no longer have access > to that particular box to research further. > > Thanks again, > Claudia -- Regards, Greg Rahn http://structureddata.org -- //www.freelists.org/webpage/oracle-l