notes on 'expert oracle'-no.2: abstract of the arch-chenjianjx的专号-iteye技术网站

notes on 'expert oracle'-no.2: abstract of the arch-chenjianjx的专栏-iteye技术网站

notes on 'expert oracle'-no.2: abstract of the arch-chenjianjx的专栏-iteye技术网站
2011年09月01日
　　 1. Database and Instance
　　Database: Static Contents in Disks 
　　Instance: Processes/Threads and Memory running on a Database 
　　A Database can only be opened by a single instance. 
　　An instance can only open a single Database. And it dies when it cloese the Database. 
　　2.SGA:  A shared memory area by all the processes/threads of an instance 
　　3.Connection
　　1.Conenction to a Dedicated Server: Every connection occupies a exclusive server process. Too many connections may bring the server down. 
　　2.Conenction to a Shared Server: 
　　a. All the connections shared a single server process.(Pooling behind the scene) 
　　b. Dispatcher + SGA Queues