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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?

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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.

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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.

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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

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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?

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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"

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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.

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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 <_<

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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.

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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.

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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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