RE: Flashback_on disabled automatically
- From: Martin Brown <martinfbrown@xxxxxxxxxxx>
- To: <john.hallas@xxxxxxxxxxxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 4 Jan 2010 10:30:43 -0500
You may want to try a shell script that monitors free space in the recovery
area. It's also possible that you've set a guaranteed restore point and forgot
about it? Or maybe the db_flashback_retention_target is larger than it needs to
be? Just some things to look at without knowing your requirements.
From: John.Hallas@xxxxxxxxxxxxxxxxxx
To: oracle-l@xxxxxxxxxxxxx
Date: Mon, 4 Jan 2010 14:06:23 +0000
Subject: Flashback_on disabled automatically
I believe that there is a fundamental flaw in how flashback is managed in a
database.
If I make the decision, based on business requirements and technical reasons,
that I want flashback logging to be enabled for a database then I would expect
that to remain the situation.
However Oracle can disable flashback and not really inform the user at all. Yes
there is a message in the alert log
Errors in file /app/oracle/admin/FLASH10G/bdump/flash10g_rvwr_22255.trc:
ORA-38701: Flashback database log 77 seq 201 thread 1:
"+FRA/flash10g/flashback/log_77.2579.702048581"
ORA-17503: ksfdopn:2 Failed to open file
+PETRAFRA/flash10g/flashback/log_77.2579.702048581
ORA-15012: ASM file '+FRA/flash10g/flashback/log_77.2579.702048581' does not
exist
Thu Nov 5 15:14:07 2009
*************************************
RVWR encountered an error when writing flashback database logs.
See error stack in alert log. To avoid crashing the instance,
this instance has turned off flashback database.
*************************************
However that is very easily to miss and there is no OEM policy to raise an
alert.
I have tried to cause flashback to be automatically turned off but I cannot
replicate it very easily as the archivelog fills prior to flashback being
turned off.
I have logged an SR with Oracle as I want to develop a test so that I can put
processes in place to capture the event and raise automatic alerts.
Oracle are now suggesting that this very difficult to do because of the code
paths used and are suggesting I raise an enhancement request to get an OEM
policy to be created to report when fkashback has become disabled automatically.
I favour a init.ora parameter which asks “Should the database hang if
flashback_area full” which the DBA can set to true if he wants flashback
logging to be treated like archive logging. I know that the database can be
recovered without flashback but cannot with archiving but I still consider the
situation should be handled much better than it currently it.
Has anybody else got any thoughts on the matter
John
www.jhdba.wordpress.com
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