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Re: Tuning RMAN: what is rsr_l0key?

From: Charles Schultz <>
Date: Fri, 12 Oct 2007 09:06:34 -0500
Message-ID: <>

Since I was not able to get a definitive answer about what rsr_l0key is, I did some investigation. This is not rocket science, but I want to share it just in case anyone else is curious.

Apparently, rsr_l0key only has relevance when row_level = 2 (also when row_type = 'RECURSIVE OPERATION'). When that is the case, rsr_l0key is the level 0 key, where rsr_pkey is the level 1 key and rsr_key is the level 2 key. I think level 2 is the max, at least it is in my database. This is the only case where nvl(rsr_pkey,-1) != nvl(rsr_l0key, -1), or to put it in english, when the parent key is not exactly the same as the level 0 key, even if they are both null.

I am not exactly sure why the rc_rman_status view wants to union in all the null level 0 keys. It seems like you would grab all the regular rsr keys, and if you want parent information, go get it with a hierarchy or something.

However, I am even more perplexed about the original query. Why select a session key using a very generic timestamp that has nothing to do with your session?

Where are those rman developers when you need to ask completely inane, innocuous and inconsequential questions. =)

On 10/11/07, Charles Schultz <> wrote:
> Thanks to those that responded. I thought to make a "group" reply to
> answer you all at once, but also to make this info available to anyone else.
> Unfortunately, I have not learned anything else about rsr_l0key; the jury is
> still out for that one.
> However, after looking over my SR and hearing back from some of you, we
> will be applying bug patch 5620640 over the weekend and hopefully that will
> help.
> On 10/11/07, Charles Schultz <> wrote:
> >
> > We are having some serious performance problems with the RMAN catalog;
> > Oracle suggested that we upgraded to but I think that has only
> > moved the bottlenecks to different parts of the architecture. Right now, we
> > are getting killed by this rman query:
> >
> > Our RC_RMAN_STATUS has ~500 k rows. Looking at the view, there is a
> > union for rows were rsr.rsr_l0key is null. A third of our rows have a
> > null value for that column. What is rsr_l0key? It is not documented.
> >
> > I am sure our problem is related to volume, but I am not convinced that
> > this should be the problem. I mean, come on, this is a measly 500,000
> > rows.
> > We are in the progress of creating a colocated catalog to partition the
> > load a little. But I am still curious about the internals of rman,
> > especially since it is not documented.
> >
> > --
> > Charles Schultz
> --
> Charles Schultz

Charles Schultz

Received on Fri Oct 12 2007 - 09:06:34 CDT

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