Re: log file format

>
> > So in order to identify these rows I need to build something like a
> > ROWID dictionnary.
> > The problem with partitionned tables is that queries can imply rowid
> > modification and it's very hard to notice.
> >
>
> Nope, you lost me there. Queries don't modify rows, and aren't in the redo
> logs at all. DML is. Maybe that's what you meant.
>

Sorry I keep on using the word "query" for every transactions. Yes I meant DML.

>
> > So I was asked to look in the log files in order to determien if it's
> > possible to use them directly instead of using logminer.
> >
>
> I confess up front I've never checked for partitioned tables. But every
> piece of DML stored in the logs includes the rowid, and I would be highly
> surprised if an update to a row in a partition didn't likewise include the
> rowid. And I don't quite see why one rowid is any more difficult to notice
> than another -it's all Base-64 code crap anyway! Have you applied the
> DBMS_ROWID package against the ROW_ID column in v$logmnr_contents to turn it
> into something rather more workable (like decimal!).
>

The problem with partitionned tables is as follow :

suppose you make an update that cause a row to be moved from a partition to another with logminer you will get those sql_redo:

• update ... where rowid = 'oldrowid'
• delete ... where rowid = 'oldrowid'
• insert ... where rowid = 'newrowid'

So it seems to you there are three operations whereas there's only one.

So if you have an automized process that is reacting to insert for example,it's problematic.

> > I've never found third party tools.
> > Are they more efficient?
>
> Wouldn't have a clue. I've only heard about them by reputation, and I've
> never worked with them. But it depends how you define 'efficient'! They
> probably have nice point-and-click interfaces, and don't require you to do
> battle with mangled package/procedure syntax, but I doubt they do much more
> than Log Miner itself -it's the same redo stream they are analysing, after
> all.
>

OK I'm not interested in a visual tool cause I'm planning to build an application that will run logminer. So it's easiest to have the API.

> > If so , it means that there may be more to find in the log files.
> >
> > Do you know if Oracle agrees giving or sending their log file format?
>
> OK, so you wonder whether the column descriptions in v$logmnr_contents
> accurately reflects the actual composition of the redo log stream, or
> whether there are bits and pieces it misses out. I doubt it misses anything
> major out, but Jonathan or Steve could probably tell you for sure. The
> speak fluent hexadecimal.

Maybe there's more to get from the log file but it was difficult to implement.
As it is the first version of this tool, it may not use all the capacity of the logs.
I've read that the version shipped with Oracle 9 have several more functionalities.So...

Moreover the fact that logminer doesn't work with Oracle 7 is also a problem for me.  

> Regards
> HJR
Received on Wed May 23 2001 - 04:37:01 CDT