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how to clean up Flash Back Log ?

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peterx
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Posts: 208
Joined: Wed Feb 09, 2011 7:07 am

how to clean up Flash Back Log ?

Postby peterx » Tue Aug 06, 2013 9:27 am

hi Tim,

Code: Select all

NAME                           SPACE_LIMIT(GB) SPACE_USED(GB) SPACE_USAGE(%) SPACE_RECLAIMABLE(GB) SPACE_RECLAIMABLE(%) NUMBER_OF_FILES
------------------------------ --------------- -------------- -------------- --------------------- -------------------- ---------------
/Flash_Recovery_Area/xxxxxxx                30         11.426         38.086                10.938               36.458             234

FILE_TYPE            PERCENT_SPACE_USED PERCENT_SPACE_RECLAIMABLE NUMBER_OF_FILES
-------------------- ------------------ ------------------------- ---------------
CONTROL FILE                          0                         0               0
REDO LOG                              0                         0               0
ARCHIVED LOG                          0                         0               0
BACKUP PIECE                          0                         0               0
IMAGE COPY                            0                         0               0
FLASHBACK LOG                     38.09                     36.46             234
FOREIGN ARCHIVED LOG                  0                         0               0




I read some official doc. Oracle claimed that the FLASHBACK LOG can't backup and they will manage automatically,
if the FRA needed space, they will delete and reuse the space.

I want to ask is, that means, the real needed flash back log (24hrs retention) is equal to

Code: Select all

FLASHBACK LOG                     38.09                     36.46             234

PERCENT_SPACE_USED - PERCENT_SPACE_RECLAIMABLE, right?
Then, if i monitor the figure, do i needed to monitor "PERCENT_SPACE_USED - PERCENT_SPACE_RECLAIMABLE", rather
than PERCENT_SPACE_USED ?


And, my retention is set to 24hrs, but in my FLASHBACK LOG folder have some log is created at JUN.
I do want to know, any method to find the "can delete" flashback log ?

thanks.

peterx
Senior Member
Posts: 208
Joined: Wed Feb 09, 2011 7:07 am

Re: how to clean up Flash Back Log ?

Postby peterx » Wed Aug 07, 2013 9:57 am

Seems, Oracle said that Flashback log is managed by itself.

I search from internet, only two method to clean or delete the flashback log.

1. turn off the flashback and turn on again
but, this will lost all the before flashback log.

2. try to shrink the FRA size, then the flashback will be delete automatically.

I think shrink the FRA size is a possible method, but any bad effect while shrink the FRA in the production environment ?

thanks.

Tim...
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Location: England, UK
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Re: how to clean up Flash Back Log ?

Postby Tim... » Wed Aug 07, 2013 4:14 pm

Hi.

Sorry I've taken so long to reply. I an in South America at the moment, so I don't have a lot of time to myself. :)

Shrinking the size is ok, but remember, the FRA may contain other things, like backups and archived redo logs. Depending on how you use the FRA, reducing its size could be a negative issue.

For the most part, you can just leave Oracle to manage it.

Cheers

Tim...
Tim...
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peterx
Senior Member
Posts: 208
Joined: Wed Feb 09, 2011 7:07 am

Re: how to clean up Flash Back Log ?

Postby peterx » Thu Aug 08, 2013 7:35 am

hi Tim,

Never mind for you late reply, in fact, very thanks for you reply always!

Then, if really turn on the flashback (maybe for a few month). The FRA will be used up to 100% ?
But..., maybe the recliamable = 95% ?

thanks.

Tim...
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Posts: 18437
Joined: Mon Nov 01, 2004 5:56 pm
Location: England, UK
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Re: how to clean up Flash Back Log ?

Postby Tim... » Thu Aug 08, 2013 10:44 am

Hi.

Yes. Oracle will try to keep things as long as possible, only clearing things out when more space for new items is required. This gives you the maximum recovery window.

Cheers

Tim...
Tim...
Oracle ACE Director
Oracle ACE of the Year 2006 - Oracle Magazine Editors Choice Awards
OakTable Member
OCP DBA 7.3, 8, 8i, 9i, 10g, 11g
OCP Advanced PL/SQL Developer
Oracle Database: SQL Certified Expert
My website: http://www.oracle-base.com
My blog: http://www.oracle-base.com/blog


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