Re: RE: difference between child and parent latches?
- From: <ryan.gaffuri@xxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Tue, 23 Mar 2004 9:19:49 -0500
thanks for your help. I want to drill a little deeper.
1. v$latch and v$latch_parent seem to be identical? What am I missing?
2. I don't quite understand the level# field? level of what?
>
> From: K Gopalakrishnan <kaygopal@xxxxxxxxx>
> Date: 2004/03/23 Tue AM 07:57:34 EST
> To: oracle-l@xxxxxxxxxxxxx
> Subject: Re: RE: difference between child and parent latches?
>
> Ryan:
>
> My understanding is whenever/whereever,
>
> a)single latch is not sufficiant to protect the entire data structure
> b)the contention for that particular latch is severe and the structure
> can be logically split in to multiple data structures
>
> multiple latches are implemented and grouped as parent-child
> relationships.
>
> So to answer your question, both are essentially same, but the child
> latches are created during instance startup (parents are defined in the
> code) and the number of children can be controlled by some underscore
> parameters.
>
> Hope this answers your question ! if not Ask Steve Adams
>
> Regards,
> Gopal
>
>
>
> --- ryan.gaffuri@xxxxxxx wrote:
> > i'm still having trouble understanding what the real difference is
> > between a parent latch and a child latch?
> > >
> > > From: K Gopalakrishnan <kaygopal@xxxxxxxxx>
> > > Date: 2004/03/23 Tue AM 04:28:38 EST
> > > To: oracle-l@xxxxxxxxxxxxx
> > > Subject: RE: difference between child and parent latches?
> > >
> > > Paul:
> > >
> > > You will have only one latch if your shared pool is less than 250
> > MB.
> > > But the v$latch_children may (probably) have 7 entries, but only
> > one
> > > latch will be protecting the shared pool structures. This can be
> > > verified by checking the misses/sleeps for that particular child.
> > >
> > > Regards,
> > > Gopal
> > >
>
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