Re: oracle total recall

From: Tim Hall <tim_at_oracle-base.com>
Date: Tue, 3 Apr 2012 13:32:19 +0100
Message-ID: <CAP=5zEiFn8853RKXXmL1O0F+QEFZe-q87tngRmNVga79s-LOvA_at_mail.gmail.com>



Hi.

I agree with Ilmar, your post does sound a little confusing because you do sound like you are talking about flashback database. :)

Ignoring that, what it sounds like you are saying is the more changes you make to the table, the longer a flashback operation takes to complete.

Well, that's kinda obvious since the way the undo-based flashback operations work is to use the undo in the undo tablespace (and flashback data archive if present and required) to build up a specific point in time representation of the data. In the case of flashback table, this representation of the data is used to alter the table data, effectively recovering to the previous state. This is a transactional operation though, so the next flashback operation you try will have more data to wade through to get your result. The same way, flashing back 1 minute will be quicker than flashing back 1 week, since the amount of undo processing will be vastly less (assuming even load over time etc.)

Sorry if I misunderstood your point...

Cheers

Tim...

On Tue, Apr 3, 2012 at 1:10 PM, Remigiusz Sokolowski <remigiusz.sokolowski_at_nordea.com> wrote:
> W dniu 03.04.2012 13:36, Ilmar Kerm pisze:
>> On Tue, Apr 3, 2012 at 2:00 PM, Remigiusz Sokolowski
>> <remigiusz.sokolowski_at_nordea.com> wrote:
> [..]
>> I somehow got the feeling, that maybe you are mixing up two different
>> flashback features:
>> * flashback database, for a very quick entire database rollback
>> * flashback archive (total recall), mainly for providing historical
>> views of a table data for a long period in time, by storing the needed
>> undo records
>>
>
> That is an interesting statement.
> I certainly do not use flashback database, but flashback table
> statements (thus this will use data from UNDO tablespace).
> So, if I understand You well, my idea that flashback table will use
> flashback archives if called on flashback-archive-enabled table is not
> really a reality ? ;-)
> That would be something I look for.
>
> Regards
> Remigiusz
> --
> Pole nakazi
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Received on Tue Apr 03 2012 - 07:32:19 CDT

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