Shared memory allows an application to allocate a chunk of memory which can be viewed by other processes. Oracle uses shared memory to create the System Global Area (SGA) which all Oracle processes must be able to access.
Semaphores act as flags for shared memory. Semaphores are either set on or off. When an Oracle process accesses the SGA (in shared memory) it will check for a semaphore for that portion of memory. If it finds a semaphore set on for that portion of memory that process will sleep and check again later. If there is no semaphore set on for that portion of memory it will set one on and proceed with its operation. When it is done it will switch that semaphore back to off.
[@more@]来自 “ ITPUB博客 ” ，链接：https://blog.itpub.net/37724/viewspace-1008197/ ，如需转载，请注明出处，否则将追究法律责任。
上一篇：
辛苦赚钱的目的
下一篇：
软链接存储内容的验证
请登录后发表评论
登录
全部评论
