Oracle creates a redo change vectordescribing how to make that change, and it creates the vectors before it makesthe changes. Historically, it created the undo change vector before it createdthe
Oracle creates a redo change vector describing how to make that change, and it creates the vectors before it makes the changes. Historically, it created the undo change vector before it created
Oracle creates a redo change vectordescribing how to make that change, and it creates the vectors before it makesthe changes. Historically, it created the undo change vector before it createdthe
a3次旅行 3 travel[translate] aSCENEINDEX SCENEINDEX[translate] a沈星辰 正在翻译,请等待...[translate] aCome play with me. I have something to show you 来戏剧与我。 我有某事吨展示您[translate] asave,undo,redo 保存,解开,再做[translate]...
1.Create a redo change vectordescribing how to insert an undo record into an undo block. --创建undo record对应的redochange vector。 2.Create a redo change vector forthe data block change. --创建data block对应的redochange vector。 3.Combine the redo change vectorsinto a redo record and writ...
After MySQL 5.6, the undo tablespace can be configured as a separate file, but it must be configured in the configuration file in advance. It takes effect after the database initialization is completed, and the number of undo log files cannot be changed. ...
Oracle Redo and Undo 《Oracle Core Essential Internals for DBAs and Developers》 在我看来,Oracle最重要的特性,是Oracle 6版本出现的change vector,描述数据块改变的机制,也是Redo和undo的核心。 but in my opinion the single most important feature of Oracle is one that first appeared in version 6: the...
REDO LOG是顺序写的文件,每次写入的数据量很小,TEMP文件虽然也就有部分顺序读写的特点,但是TEMP每次读写的数据量较大,和REDO 的特性不同。UNDO是典型的随机读写的文件,索引更是以单块读为主的操作。 REDO LOG 的产生十分频繁,几乎每秒钟都有几百K 到几M 的RED LOG 产生,甚至某些大型数据库每秒钟产生的REDO...
First time – just to prepare the redo entries and 2nd time to make the change to data/undo block .. My assumption is : Let us say : Update employee set sal=1000 where emp_id in (23,24) ; and let’s say there are 2 rows and they are in 2 blocks (one in each block).. ...
To undo something on Mac, you can use the Cmd+Z shortcut. The last action on your Mac will be undone. To redo an action on Mac, press Cmd+Z+Shift.