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Flashback Database [message #618936] Wed, 16 July 2014 11:07 Go to next message
jerstep
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Is it common to use Oracle Flashback Database to rollback code releases (DDL, DML) to Development and/or Production environments instead of writing rollback scripts ? What are the pros/cons of such an approach?
Re: Flashback Database [message #618938 is a reply to message #618936] Wed, 16 July 2014 11:09 Go to previous messageGo to next message
John Watson
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Welcome to the forum. Please read our OraFAQ Forum Guide and please read How to use [code] tags and make your code easier to read

This is what flashback might have been designed for. Repeatable testing runs, too.
Re: Flashback Database [message #618941 is a reply to message #618936] Wed, 16 July 2014 11:29 Go to previous messageGo to next message
Michel Cadot
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There are things that are very difficult if not impossible to roll back.
And there are things that are very long to roll back when flashback might be very fast.

Re: Flashback Database [message #618989 is a reply to message #618936] Thu, 17 July 2014 03:32 Go to previous messageGo to next message
gazzag
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Like everything, the answer is "it depends" Smile

I don't use Flashback on production as there is an obvious overhead - flashback logs have to be written, for example. Also, to flashback a database means that all work done on that database will be rolled back which will probably not be acceptable for your users.

Generally, I use Flashback on test or UAT systems. This means that the database can be returned to a known state at any point during the testing phase.

HTH
-g
Re: Flashback Database [message #618991 is a reply to message #618989] Thu, 17 July 2014 03:37 Go to previous messageGo to next message
Michel Cadot
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Quote:
I don't use Flashback on production as there is an obvious overhead - flashback logs have to be written, for example.


But is this noticeable for the application and application users?
And is this not acceptable to counterbalance a downtime of several hours (if a whole day) in restoring and recovering in case of errors?

Re: Flashback Database [message #618992 is a reply to message #618991] Thu, 17 July 2014 03:51 Go to previous messageGo to next message
gazzag
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Quote:
Like everything, the answer is "it depends"
Re: Flashback Database [message #618993 is a reply to message #618992] Thu, 17 July 2014 03:54 Go to previous messageGo to next message
Michel Cadot
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This is why I asked what leads you to not use it on your production databases.

Re: Flashback Database [message #618997 is a reply to message #618993] Thu, 17 July 2014 04:15 Go to previous messageGo to next message
gazzag
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Why don't you go and clarify your first post in this thread instead of tearing mine to pieces? No wonder your post count is so high <_<
Re: Flashback Database [message #618999 is a reply to message #618997] Thu, 17 July 2014 04:27 Go to previous messageGo to next message
Michel Cadot
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I didn't want to bother you, it was just to help other knowing why one decides something in this case.
As you said "it depends" so your example may be important.

Re: Flashback Database [message #619001 is a reply to message #618989] Thu, 17 July 2014 04:46 Go to previous messageGo to next message
John Watson
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gazzag wrote on Thu, 17 July 2014 09:32
Like everything, the answer is "it depends" Smile

I don't use Flashback on production as there is an obvious overhead - flashback logs have to be written, for example. Also, to flashback a database means that all work done on that database will be rolled back which will probably not be acceptable for your users.

Generally, I use Flashback on test or UAT systems. This means that the database can be returned to a known state at any point during the testing phase.

HTH
-g
Exactly my usual working practice. That having been said, I suspect that the overhead of flashback is not significant. Theoretically, one can calculate it. v$flashback_database_stat shows the volumes of data written to data files, online redo logs, and flashback logs. So one should be able work out what proportion of your I/O capacity is taken by flashback. But I am not confident in my ability to generate meaningful data from this.
Re: Flashback Database [message #619013 is a reply to message #619001] Thu, 17 July 2014 05:30 Go to previous message
gazzag
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I've had problems persuading management to invest in the additional disk space that they perceive as "unnecessary", John Smile
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