问一个关于IMU REDO的问题~

willing_ox

刚看了李维斯的书，好像有点区别。内容我贴出来。

So a new mechanism combining private redo and in-memory undo appeared in 10g.
     In effect, a process can work its way through an entire transaction, generating all its change vectors
and storing them in a pair of private redo log buffers. When the transaction completes, the process
copies all the privately stored redo into the public redo log buffer, at which point the traditional log
buffer processing takes over. This means that a process acquires the public redo allocation latch only
once per transaction, rather than once per change.

这样说的话，也就是redo的合并，一个事务产生的redo只索取一次redo allocate。

Yong Huang

> 刚看了李维斯的书

You're talking about Jonathan Lewis's "Oracle Core: Essential Internals for DBAs and Developers". It's on p.15 of the book.

By the way, this discussion is suitable for "Oracle专题深入讨论". But as I said, there're too few of them. So shutting it down or placing it under "Oracle数据库管理" is appropriate.