###sequnece 介绍 http://www.dba-oracle.com/t_rac_tuning_sequence_order_parameter.htm order by 可能会影响性能,但是对确认时间戳 比较重要 order子句保证序列的下一个值是行中的下一个值,不管接收请求的实例是什么.为了举例说明,假设一个序列定义为cache=20.实例1的缓存中有序列值1到20.实例2的缓存中有序列值21到40.通常,并发会话可能按以下顺序生成序列值:1.2.21.3.22.4.23和24.…
DBA_TABLES describes all relational tables in the database. Its columns are the same as those in ALL_TABLES. To gather statistics for this view, use the ANALYZE SQL statement. ALL_TABLES describes the relational tables accessible to the current user.…
一.SMON(System MONitor) 系统监控进程: 在数据库启动过程中,SMON排在CKPT进程之后,在Oracle9i中排在第六号的位置: PMON started with pid=2 DBW0 started with pid=3 LGWR started with pid=4 CKPT started with pid=5 SMON started with pid=6 RECO started with pid=7 SMON负责系统监视已经一些系统清理及恢复工作,这…