Each latch in the system has an entry in v$latch. For some latches,
this is the only entry. For others, there are additional entries in
v$latch_children. These latches have a set of children, each of which
protects a subset of the named object. For example, the ‘cache buffers
chains’ latch has a number of children; each of the child latches
protects a set of hash buckets in the db block cache.
- ryan.gaffuri_at_cox.net wrote:
> what is the difference between a parent and a child latch?
> >
> > From: "Bobak, Mark" <Mark.Bobak_at_il.proquest.com>
> > Date: 2004/03/22 Mon AM 09:33:23 EST
> > To: <oracle-l_at_freelists.org>
> > Subject: RE: difference between child and parent latches?
> >
> > Ryan,
> >
> > The main difference is that for latches which there are multiples,
> such as cache buffers chains, there is only one parent row in
> v$latch_parent, whereas there is one row per latch in
> v$latch_children. Also, the statistics are only valid in the
> corresponding view. Meaning, GETS, SLEEPS, etc are only populated in
> v$latch_children for those latches where children are present, such
> as CBC. For those where there's only one, such as shared pool, that
> data is only populated in v$latch_parent.
> >
> > -Mark
> >
> > -----Original Message-----
> > From: ryan.gaffuri_at_cox.net [mailto:ryan.gaffuri_at_cox.net]
> > Sent: Monday, March 22, 2004 7:54 AM
> > To: oracle-l_at_freelists.org
> > Subject: difference between child and parent latches?
> >
> >
> > I've been looking at v$latch_children and v$latch_parent and I'm
> having trouble seeing the differences?
> >
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Received on Mon Mar 22 2004 - 20:10:27 CST
