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redo and undo 各个公司实现机制不一样,因而和多少用户"more locking issue. means less concurrency "似无关系

neemliu(四季如冬)

WHY "2 sqlserver do not have undo tablespace, rely on transaction log for both rollback and roll-forward. trade off is bad performance and more locking issue. means less concurrency " ?

redo and undo 各个公司实现机制不一样, INFORMIX 也是用逻辑日志实现REDO 和UNDO(物理日志记录CHECKPOINT前的IMAGE).

DB2 也用LOG FILE 实现, MS SQL 也在进步.

REDO AND UNDO都是系统使用的(ORACLE和其它). 用户是LOCK不了的, 因而和多少用户 "locking issue. concurrency "似无关系.
UNDO TABLESPACE 是逻辑概念,也是通过DATAFILE来物理实现的, 本质上也是LOGFILE.

(#3314132@0)
Last Updated: 2006-11-11
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工作学习 / 专业技术讨论 / 这个坛子有不少SQLSERVER的高手,问一下哪个学校的SQLSERVER课不错?在线等.多谢! -oracle789(BeefLover); 2006-11-9 (#3311296@0)

6年前去过CDI的SQL SERVER COURSE. INSTRUCTOR 很不错, 讲的条理清晰. -looi500(looi); 2006-11-9 (#3311474@0)

多谢回答. 不过现在CDI好象没有SQLSERVER的课. 我计划跟跟形势朝MCITP:DBA努力一下, 好象没有(国人办的)学校提供. -oracle789(俺也要学SQLSERVER); 2006-11-9 (#3311509@0)

CDI 的WEB SITE -looi500(looi); 2006-11-9 (#3311538@0)

多谢.我还以为是CDI COLLEGE呢. 不过目前没有那么多的BUDGET. -oracle789(俺也要学SQLSERVER); 2006-11-9 (#3311919@0)

没银问啥,自摸吧 -binc(管理员); 2006-11-12 (#3316562@0)

不知道你的背景和学这个做何打算? 个人认为, 你要是windows/.net 程序员的话, 可以自己看看书, 考一门微软的课就比上那些培训强一些... 要是没有背景的话, 我就不好说了... 用SQL Server的都不是什么大系统, 很少有专门的DBA... -poohbear(毛毛熊); 2006-11-9 (#3311743@0)

这话说大了吧。SQL SERVER用在大系统的多了去了。就我所知，很多大公司都是跟微软有Affiliate的关系，只用微软的产品的。虽然我很讨厌微软，但这是事实。 -bdbs(不多不少); 2006-11-9 (#3311751@0)

大公司都会用微软的产品, 但是很少用到核心上, 连微软自己前些年还被指用Oracle哪... 我现在工作的公司不是什么大公司, 就只用SQL SERVER做APP... 核心数据前20年用mainframe, 现在正要往oracle上移...APP程序员为自己的SQL负责, 我当然希望有DBA啊 -poohbear(毛毛熊); 2006-11-9 (#3311785@0)

我想稳定性是问题, SQL SERVER隔三差五地就要重启动, MAINFRAME只停电的时候重启动过, 我以前的公司用Oracle, 也没见重启动... -poohbear(毛毛熊); 2006-11-9 (#3311801@0)

NASDAQ算不算大系统？？？ -zhihaoxx()(); 2006-11-9 (#3311982@0)

既然这么说了, 那就上培训班, 去nasdaq.... That's absolutely a wonderful path! -poohbear(毛毛熊); 2006-11-9 (#3312107@0)

估计没有人回答你的问题，是因为高手都不是学校里学出来的。:( -bdbs(不多不少); 2006-11-9 (#3311761@0)
兄弟们,没想到我这个问题引起HIGH-LEVEL的争论. 你看我的ID就知道俺是啥出身.但SQLSERVER的崛起是个不争的事实. -oracle789(俺也要学SQLSERVER); 2006-11-9 {273} (#3311976@0)
前段时间看过一个PAPER,在联想到公司的变化,彻底改变俺以前鄙视MS的心态.现在SQLSERVER的市场占有率已接近ORACLE(千万别听LARRY和CHARLES瞎摆活,提到MS,就说什么那个公司在SEATTLE的那个), 而且用到MISSION-CRITICAL的比例和ORACLE不相上下. 咱不说这个了, 快指点哪有2005 ADMIN的课吧. 急着呢!

做Oracle的转MS SQL还用学什么嘛？随便找点文档看看就好了 -hard20(hard20); 2006-11-9 (#3311992@0)
老大对DB2什么看法？ -thisunreal(饭得志); 2006-11-10 (#3312260@0)

如果不想去美国,就不要考虑db2，加拿大db2职位太少。 -ebusiness(每天进步多一些); 2006-11-10 (#3312264@0)

还没成热点话题，算不上争论。呵呵。不过如hard20所说，你有那家底，找什么学校呀。看这里：
-bdbs(不多不少); 2006-11-10 (#3312344@0)

这个俺早就DOWN下了. -oracle789(俺也要学SQLSERVER); 2006-11-10 (#3312362@0)

after you learn sqlserver, you will feel confident that mission critical system will stay with Oracle. for example. -walkthrough(walkthrough); 2006-11-11 {612} (#3313949@0)
1. sqlserver t-sql error handling has long way to catch up with plsql exception handling.
2. sqlserver do not have undo tablespace, rely on transaction log for both rollback and roll-forward. trade off is bad performance and more locking issue. means less concurrency .
3. sqlserver is on windows platform. oracle run majorly on unix.
I don't want to mention others, like row level locking, HA, security... etc.

sqlserver advantage is that it's a small shop, easy to start with. DTS is very good tool. but I don't think it's good enough to handle complicated business and hundreds of concurrent users.

redo and undo 各个公司实现机制不一样,因而和多少用户"more locking issue. means less concurrency "似无关系 -neemliu(四季如冬); 2006-11-11 {548} (#3314132@0)
WHY "2 sqlserver do not have undo tablespace, rely on transaction log for both rollback and roll-forward. trade off is bad performance and more locking issue. means less concurrency " ?

redo and undo 各个公司实现机制不一样, INFORMIX 也是用逻辑日志实现REDO 和UNDO(物理日志记录CHECKPOINT前的IMAGE).

DB2 也用LOG FILE 实现, MS SQL 也在进步.

REDO AND UNDO都是系统使用的(ORACLE和其它). 用户是LOCK不了的, 因而和多少用户 "locking issue. concurrency "似无关系.
UNDO TABLESPACE 是逻辑概念,也是通过DATAFILE来物理实现的, 本质上也是LOGFILE.

you can join my study group. I passed 70-431 last month. currently on upgrading to .NET 2.0. DBA would be my next goal. -sunday8(sunday8); 2006-11-10 (#3312273@0)

Do you have MS 70-431 Ebook CD? Can I borrow and make a copy? Thanks. -happycat(Kiki); 2006-11-10 (#3312925@0)

no. I don't have the CD. sorry.. -sunday8(sunday8); 2006-11-10 (#3313358@0)

Thanks anyway. -happycat(Kiki); 2006-11-11 (#3314092@0)

你最好还是能强调你的长处，不要什么都不精. 把OCM考出来比MSSQL有钱图. -binc(管理员); 2006-11-13 (#3317515@0)

@Calgary

redo and undo 各个公司实现机制不一样,因而和多少用户"more locking issue. means less concurrency "似无关系

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