V$FLASHBACK_DATABASE_LOG 和 V$FLASHBACK_DATABASE_STAT
记录一下ORACE 10g? 1Z0-043 中关于闪回的两个视图
SQL> col object_name for a30;
SQL>
SQL> select o.object_name,o.object_type
? 2??? from dba_objects o
? 3?? where o.object_name like 'V$FLASH%';
OBJECT_NAME?????????????????????????????????? ????? OBJECT_TYPE
------------------------------?????????????????????? -------------------
V$FLASHBACK_DATABASE_LOG???????????????????????????? SYNONYM
V$FLASHBACK_DATABASE_LOGFILE???????????????????????? SYNONYM
V$FLASHBACK_DATABASE_STAT????????????? ? ? ? ? ? ? ? SYNONYM
V$FLASHBACK_TXN_GRAPH??????????????????????????????? SYNONYM
V$FLASHBACK_TXN_MODS???????????????????????????????? SYNONYM
V$FLASH_RECOVERY_AREA_USAGE????????????????????????? SYNONYM
V$FLASHBACK_DATABASE_LOG
显示闪回数据的信息，用来评估当前负载下需要的闪回空间
v$flashback_database_log
Name???????????????????????????????????????????????????? ? Description
------------------------------??????????????????????? --------------------------
OLDEST_FLASHBACK_SCN? Lowest system change number (SCN) in the flashback data,for any incarnation
????????????????????????????????????????????????闪回数据最小的scn
OLDEST_FLASHBACK_TIME????? Time of the lowest SCN in the flashback data,for any incarnation
????????????????????????????????????????????????闪回数据最小的时间
RETENTION_TARGET????????????????Target retention time (in minutes)
????????????????????????????????????????????????闪回保留时间
FLASHBACK_SIZE?????????????????? ? Current size (in bytes) of the flashback data
?????????????????????????????????????????????????闪回数据大小
ESTIMATED_FLASHBACK_SIZE? Estimated size of flashback data needed for the current target retention
?????????????????????????????????????????????????评估满足当前闪回保留时间，需要的闪回空间的大小
??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
V$FLASHBACK_DATABASE_STAT
显示数据库收集到的闪回信息
Name???????????????????????????????????????????? Description
------------------------??????????? --------------------------------
BEGIN_TIME??????????? Beginning of the time interval?
?????????????????????????????? ?一段时间间隔的起始时间???
END_TIME????????????????End of the time interval??
??????????? ??????????????????? ?一段时间间隔的结束时间
????????????????????????????
FLASHBACK_DATA????Number of bytes of flashback data written during the interval????????
?????????????????????????????? ?一段时间内闪回数据的大小(bytes)?
DB_DATA????????????????? Number of bytes of database data read and written during the interval
?????????????????????????????????一段时间内数据库读写大小(bytes)??
REDO_DATA??????????????Number of bytes of redo data written during the interval
?????????????????????????????? ?一段时间内redo 数据的大小(bytes)
ESTIMATED_FLASHBACK_SIZE??? Value of ESTIMATED_FLASHBACK_SIZE in V$FLASHBACK_DATABASE_LOG at the
?????????????????????????????????????????????? end of the time interval
???????????????????????? ????????? 一段时间间隔的结束时，评估需要闪回空间的大小
转自：http://blog.csdn.net/lwei_998/article/details/6125403
OCP试题
186.?You?executed?the?following?query?in?your?database: FROM?V$FLASHBACK_DATABASE_LOG? What?would?you?determine?from?the?output? A.the?time?when?the?last?flashback?operation?in?your?database?was?performed B.the?time?when?the?first?flashback?operation?in?your?database?was?performed C.a?list?of?flashback?operations?performed?in?your?database?using?SCN?and?time D.the?approximate?time?and?the?lowest?system?change?number?(SCN)?to?which?you?can?flash?back?your database Answer:?D 187.?These?are?the?details?about?V$FLASHBACK_DATABASE_STAT: SQL>?DESC?V$FLASHBACK_DATABASE_STAT Name?Null??Type -------------------------------?? --------?? ---------- BEGIN_TIME?DATE END_TIME?DATE FLASHBACK_DATA?NUMBER DB_DATA?NUMBER REDO_DATA?NUMBER ESTIMATED_FLASHBACK_SIZE?NUMBER Which?two?statements?regarding?the?V$FLASHBACK_DATABASE_STAT?view?are?true??(Choose?two.) A.BEGIN_TIME?is?the?time?at?which?Flashback?logging?is?enabled. B.END_TIME?is?the?time?at?which?the?query?is?executed?on?the?view. C.REDO_DATA?is?the?number?of?bytes?of?redo?data?written?during?the?interval. D.This?view?contains?information?about?flashback?data?pertaining?to?the?last?24?hours. E.FLASHBACK_DATA?is?the?amount?of?flashback?data?generated?since?the?database?was?opened. Answer:?CD
