Oracle 视图 V$FLASHBACK_DATABASE_STAT 官方解释,作用,如何使用详细说明

本站中文解释

US

V$FLASHBACK_DATABASE_STATUS是一个视图,每次从V$INSTANCE视图中获取数据库的名称,建立新的闪回状态信息。该视图显示闪回操作的当前状态和进度等信息,以及可以对闪回模式进行设置。

Oracle Flashback Database可以让数据库管理员滚回数据库到一个特定的时间点,也可以将数据库滚回到一个特定的SCN。Flashback Database通过日志和快照之间的交互实现,以实现恢复和闪回操作。

要使用V$FLASHBACK_DATABASE_STATUS,首先需要使用FLASHBACK_ON参数开启Flashback Database模式,具体步骤如下:

1. 使用ALTER SYSTEM选项启动闪回模式:
ALTER SYSTEM FLASHBACK ON;

2. 查看V$FLASHBACK_DATABASE_STATUS视图:
SELECT * FROM V$FLASHBACK_DATABASE_STATUS;

官方英文解释

V$FLASHBACK_DATABASE_STAT displays statistics for monitoring the I/O overhead of logging flashback data. This view also displays the estimated flashback space needed based on previous workloads.

Column Datatype Description

BEGIN_TIME

DATE

Beginning of the time interval

END_TIME

DATE

End of the time interval

FLASHBACK_DATA

NUMBER

Number of bytes of flashback data written during the interval

DB_DATA

NUMBER

Number of bytes of database data read and written during the interval

REDO_DATA

NUMBER

Number of bytes of redo data written during the interval

ESTIMATED_FLASHBACK_SIZE

NUMBER

Value of ESTIMATED_FLASHBACK_SIZE in V$FLASHBACK_DATABASE_LOG at the end of the time interval

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data


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