Oracle Processes - Expert Oracle Database Architecture - page 201

parameter is set to a non-zero value (derived from CPU_COUNT * PARALLEL_THREADS_PER_CPU * 2 ). For example, on
my two CPU box ( CPU_COUNT parameter is 2 and PARALLEL_THREADS_PER_CPU parameter is 2), we see the following
eight parallel execution servers running:

$ ps -ef | grep ora_p00 | grep -v grep

oracle 31086 1 0 Apr06 ? 00:00:03 ora_p000_ORA12CR1
oracle 31088 1 0 Apr06 ? 00:00:05 ora_p001_ORA12CR1
oracle 31104 1 0 Apr06 ? 00:00:02 ora_p002_ORA12CR1
oracle 31106 1 0 Apr06 ? 00:00:02 ora_p003_ORA12CR1
oracle 31108 1 0 Apr06 ? 00:00:02 ora_p004_ORA12CR1
oracle 31110 1 0 Apr06 ? 00:00:02 ora_p005_ORA12CR1
oracle 31112 1 0 Apr06 ? 00:00:02 ora_p006_ORA12CR1
oracle 31114 1 0 Apr06 ? 00:00:02 ora_p007_ORA12CR1

■ Tip See Chapter 14 for full details on parallel processing.

Summary
We've covered the files used by Oracle, from the lowly but important parameter file to data files, redo log files,
and so on. We've taken a look inside the memory structures used by Oracle, both in the server processes and the
SGA. We've seen how different server configurations, such as shared server versus dedicated server mode for
connections, will have a dramatic impact on how memory is used by the system. Lastly, we looked at the processes
(or threads, depending on the operating system) that enable Oracle to do what it does. Now we are ready to look at the
implementation of some other features of Oracle, such as locking, concurrency controls, and transactions.