Oracle Flashback Technologies - 估算不同时间段闪回日志的产生量

时间:2023-03-08 17:31:55

Oracle Flashback Technologies - 估算不同时间段闪回日志的产生量

v$flashback_database_stat
监控闪回数据的i/o开销的统计信息,根据之前的系统负载估算闪回空间需求。时间间隔是一小时。

SQL> select * from v$flashback_database_stat  order by begin_time;

BEGIN_TIM END_TIME  FLASHBACK_DATA    DB_DATA  REDO_DATA ESTIMATED_FLASHBACK_SIZE
--------- --------- -------------- ---------- ---------- ------------------------
-JUN- -JUN-
-JUN- -JUN- SQL>

v$flashback_database_stat说明

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