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Read undo log files in MAXDB

Former Member
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Hey.

I'm new to this forum...

I have installed MAXDB 7.8.02.21.

I want to rollback some (not all) transactions based on your redo/undo log to a certain past time.

Therefore, I would like to read the redo/undo MAXDB logs files and choose which transactions to undo.

I cannot find a way to read the MAXDB log files !

Is there a solution ?

Remark:

Rollingback manually through running undo SQL order would be fine... My question is not on the existence of a rollback interface... I just need to read the undo/redo log entries.

Thanks in advance.

Robert.

Accepted Solutions (0)

Answers (2)

Answers (2)

lbreddemann
Active Contributor
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Hello Robert,

Markus comments are all correct and true.

There is no functionality available to make the redolog entries readable in a way that would allow to undo certain statement.

And even more important, also mentioned by Markus, this would likely make your database inconsistent.

This is especially true, when the consistency isn't enforced by constraints (as it is the case with SAP databases).

What's interesting to me is: what kind of use case do you have in mind for that?

Undoing user actions on complex data always needs to be implemented specifically on application level and reflected in the database level. So, I assume that it's not about that, is it?

So what is it you wan to do with such a functionality?

regards,

Lars

Former Member
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Thanks for your info and questions.

Beyond undoing transactions, I am indeed also interested in reading actions performed by users/transactions to improve/tune an application and audit users requests.

At MAXDB level, would you have a functionality that could help me identify what SQL request has been performed by a user or by a transaction?

Bye.

Robert.

markus_doehr2
Active Contributor
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> I want to rollback some (not all) transactions based on your redo/undo log to a certain past time.

> Therefore, I would like to read the redo/undo MAXDB logs files and choose which transactions to undo.

There is no such functionality in MaxDB.

Markus

Former Member
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Thanks for your reply Markus.

I have continued to search your web today and found a command that could be helpfull : DBMGETF linked with a SAP command called SM49. The URL is

http://wiki.sdn.sap.com/wiki/display/MaxDB/SAPMaxDBTools

Is there a way to read redo files with these commands? I could not find anything more helpfull than this URL.

Sincerely,

Robert.

markus_doehr2
Active Contributor
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"redo log" are binary, they are not human readable. Morever, they don't contain easy statements as "insert value X on database Y to table Z".

The support may be able to use x_console to read some the data but there are no tools to roll back transaction that are already saved in the database (commited). This would alter the database integrity

The tool you mention (dbmgetf) is to read/get text files and display/use them in an ABAP system.

What you can do is, you can create snapshots at some point, run transaction and then roll back to the snapshot you want but you can not do tihs based on the redo logs, just on the time the snapshot was created.

Markus