Books for you

If you happen to perform this extensive testing, please tell all the rest of us what you find!
Figure 7-4. Oracle I/O and chunk size interaction
Oracle 256-KB I/O Call Oracle 256-KB I/O Call
Chunk Size
One
256-KB I/O
drives all
four disks
One
256-KB I/O
hits
one disk
256 KB 256 KB 256 KB 256 KB
64 KB 64 KB 64 KB 64 KB
Oracle
8-KB I/O
Call
Oracle
8-KB I/O
Call
Oracle
8-KB I/O
Call
Oracle
8-KB I/O
Call
Each 8-KB
I/O hits one
disk
170 | Chapter 7: Oracle Performance
the time needed to complete a given task. Oracle supports parallelism within a single
SMP server and parallelism across multiple nodes, using Oracle Real Application Clusters.
Executing a SQL statement in parallel will consume more of the machine
resources??”CPU, memory, and disk I/O??”but complete the overall task faster.
Parallelism affects the amount of memory and CPU resources used to execute a given
task in a fairly linear fashion??”the more parallel processes used, the more resources
consumed for the composite task. Each parallel execution process has a Program
Global Area (PGA) that consumes memory and performs work.


Pages:
356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380