However, Oracle evolved to take advantage of systems containing
multiple CPUs through improved parallelism and more sophisticated optimization.
At the same time, the price points of Symmetric Multiprocessing systems (described
in the next section) have plummeted dramatically, making SMP systems the database
hardware servers of choice.
Figure 12-1. Typical uniprocessor system
Disk
CPU with L1 Cache
L2 Cache
Memory
I/O
Symmetric Multiprocessing Systems | 293
Even in a uniprocessor system, the server operating systems used by these systems
support multiple threads. The multicore processors are becoming common to further
enable simultaneous processing of multiple tasks. Multicore processors are integrated
circuits that contain two or more processors. Hardware platform vendors are
racing to provide more cores to differentiate their platforms.
Each thread in a server operating system can be used to support a concurrent
process, which can execute in parallel. By default, the PARALLEL_THREADS_PER_
CPU parameter in the initialization file is set at 2 for most platforms on which Oracle
runs.
Pages:
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640