This chapterexamines the mechanisms Oracle uses to create the linked liststhrough undo records and, most importantly, how the code locates the end pointsof those lists.

            --这一章主要看一下Oracle 创建和linked undo records,并且确认undorecords list的结束点。在前面的blog里提到Oracle 采用这种UNDO 机制的3个原因：readconsistency 和 Rollback，最后一个原因就是今天这篇Blog的内容。

Oracle Core 学习笔记一-- Redo 和 Undo 机制详解

http://blog.csdn.net/tianlesoftware/article/details/7626421

We’ll be lookingat the transaction table that Oracle keeps in each undo segment header block toanchor one set of linked lists, and the interested transaction list (ITL) thatOracle keeps in every single data (and index) block as the anchor toanother set of linked lists. Then we’ll take a closer look into the undosegment header to examine the transaction table control section (hereinafterreferred to as the transaction control) that Oracle uses as the anchor pointfor the final linked list.

在每个undo sement headerblock里都有一个linked lists，这个就是我们说的transaction table。同样在每个data（index） block 也会有一个linkedlist，叫interested transaction list(ITL).

We’ll finishwith a short note on LOBs (large objects), as Oracle deals with undo, redo,read consistency, and transactions differently when dealing with LOBs—or, atleast, the LOB data that is stored “out of row.”

--注意Oracle 处理普通字段与LOBs字段的区别，如果是是LOBs，Oracle 的redo ，undo，readconsistency 都会按照LOBs字段来处理，因为LOB的数据是存储是单独存储的，即“out of row”。

Oracle LOB 详解

http://blog.csdn.net/tianlesoftware/article/details/6905406

一．Conflict Resolution  --冲突解决