新的10g 比 9i 快28%, PL/SQL 快4倍， BACKUP 快6倍
比9i快 28% 提高的多吗？
pl/sql 快 4倍是说解吸速度提高4倍吗？解析的速度的提高对你的系统性能影响多少还不一定
backup提高6倍是说rman 备份吗？如果是这样偶就很清楚，这是oracle在数据块发生变化的时候使用了一个日志信息来记录发生变化的block，从而使得 rman 备份的时候根据日志只去读变化的block，原来是读整个文件的block header通过比较block的scn来确定只写哪些block到备份集而实现增量备份
现在的才是真正意义上的读增量写增量，原来是读全部写增量
如果大量的数据块都发生变化那这个功能代价可能就高了，牺牲的存储更高，读写代价更高
其实明白了原理也就那么回事
至于
1. ASM (Automatic Storage Management)
这个玩意，我给你一个说明
Predicated on S.A.M.E.
Not optimize for a specific workload
Placing, and maintaining, data files with higher than median IO rates on the outside half of the disk drives is manual task
Does not account for complexity of how rows are stored in Oracle blocks
Disk contention will occur when enough multiple processes, with sufficient demand, attempt to access the same device simultaneously
but : ASM 的限制
Has no file system (all raw devices)
Can’t host some Oracle files (e.g., trace, parameter, audit, export, tar, core,…)
Can’t easily balance load across controllers (DMP)
DBA’s cautious on ASM’s black box approachof data layout
System Administrators will abhor ASM
Lacks state of the art mirroring (Poor re-synchronizing of mirrors after failures)
Mix primary & mirror extents on each disk
Weak statistics gathering and reporting… i/o stats…
It’s a 1.0 full of defects.Virtually nobody will install 10G’s ASM for 2 years
Separate instance required to manage ASM-based databases
Adds complexity and can be a SPOF
Only supported backup method is using RMAN
ASM runs in user space, not in kernel space (recoverability concerns)
Supports placing primary on outer zone and the mirror on inner zone
With storage arrays h/w striping and mirroring is recommended
Striping is automatically selected
Course = 1MB
Fine = 128K
Does not work with Oracle Data Guard
Overhead on RAC can be significant
Simplifies Oracle database setup
“Best way to save costs is to remove complexity
所以专家断言2年内 ASM 不可能真正的被广泛应用
2. Flash Back Database (像放像机中的 REWIND)， 比如：
SQL> Flashback Database to '2:05 PM';
这个也是用存储来取代的！
这是用存储来换取的，用文件做log记录了block的变化的前印象
这个代价……如果io和存储空间是问题恐怕也不适用
3. Self Managing.
4. Automatic Tuning.
这两点……恐怕复杂性仍然不是软件自身能完成的
rman 很强大为什么很多人还用 oscopy，因为 oscopy 简单，rman 整个工具很复杂
5. HTML DB with Rapid Web Development Tool.
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