Concept内容的翻译_1025(英语水平差，发出来主要是想让大家帮我指正一下，谢谢！)

 Redo Log Buffer
  
The redo log buffer is a circular buffer in the SGA that holds information about
changes made to the database. This information is stored in redo entries. Redo
entries contain the information necessary to reconstruct, or redo, changes made
to the database by INSERT, UPDATE, DELETE, CREATE, ALTER, or DROP operations.
Redo entries are used for database recovery, if necessary.

重做日志缓冲区是SGA种一个循环的缓冲区，他用来保存数据库的变化信息，这些
信息保存在重做条目种，重做条目包含数据库重建或者重做的必须信息，这些改变
包括INSERT、UPDATE、DELETE、CREATE、ALERT、DROP操作。重做条目被用来数
据库回复，如果必要。

Redo entries are copied by Oracle database processes from the user's memory space
to the redo log buffer in the SGA. The redo entries take up continuous, sequential
space in the buffer. The background process LGWR writes the redo log buffer to
the active redo log file (or group of files) on disk

重做条目被oracle数据库进程从用户内存空间拷贝到SGA种的重做日志缓冲区。
重做条目占据连续的缓冲区空间。oracle后台进程LGWR写重做日志缓冲区到
磁盘上活动的日志文件（或者日志组中的文件）

The initialization parameter LOG_BUFFER determines the size (in bytes) of the
redo log buffer. In general, larger values reduce log file I/O, particularly
if transactions are long or numerous. The default setting is either 512 kilobytes
 (KB) or 128 KB times the setting of the CPU_COUNT parameter, whichever is greater.
 
 初始化参数：LOG_BUFFER确定重做日志缓冲区的大小，一般情况，大的值可以
 减少日志文件I/O,在长事务或者事务频繁的情况下尤为显著。该参数的缺省设置
 可以是一下其中一个，512K或者128K，或者通过CPU_COUNT参数来设置，无论
 其中那个正确设置。(这里有些不太理解)