Channel Allocation Time Limit: 1000MS Memory Limit: 10000K Total Submissions: 9669 Accepted: 4919 题目链接:http://poj.org/problem?id1129 Description
When a radio station is broadcasting over a very largearea, repeaters are used to retransm…
1.监控事例的等待:
select event,sum(decode(wait_time,0,0,1)) prev, sum(decode(wait_time,0,1,0)) curr,count(*) from v$session_wait group by event order by 4;2.回滚段的争用情况:
select name,waits,gets,waits/gets ratio from v$rollstat a,…
PGA,即程序全局区(Program Global Area),是Oracle体系机构的重要组成部分。Oracle 数据库对系统内存的总开销即是PGASGA。SGA主要由库缓存(共享SQL区和PL/SQL区)和数据字典缓存组成。而PGA包含客户端连接服务器所派生的服务器进程的集合,每个…