Flashback_on disabled automatically

From: John Hallas <John.Hallas_at_morrisonsplc.co.uk>
Date: Mon, 4 Jan 2010 14:06:23 +0000
Message-ID: <A92AF970568F9A4BAB18E10F9C64ED60691FC8189F_at_EXCH2.morrisonsplc.co.uk>

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



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Received on Mon Jan 04 2010 - 08:06:23 CST

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