Re: GRD maintenance in RAC
- From: Anand Rao <panandrao@xxxxxxxxx>
- To: racdba@xxxxxxxxxxxxx
- Date: Tue, 26 Jul 2005 10:09:31 +0530
Hey!
i think i have read this question on Metalink a long time ago !!!
...not sure of this is the same Ahmed :-)
not a problem,
Both LMD (GES) and LMS (GCS) maintain the DLM database which is
otherwise called as the GRD in Oracle 9i and 10g. LMD performs a very
crucial function called Deadlock Detection as well lock database
canning and lock conversion. So, locking operations are made possible
because LMD handles the lock database or shall we say maintains the
GRD. There are many resource structures inside the GRD and these
structures are what comprises the GRD and maintained by GCS and GES.
In Oracle 9i, LMON did the DLM reconfiguration (on instance crash or
instance join/leaving). In Oracle 10g it is the LMS which does the
remastering. The housekeeping task of cleaning the DLM database
(cache) is also done by LMON and i think LMS takes this job from
Oracle 10g.
Other than this i believe PMON has a lot of DLM calls stacked away in
its code in RAC enabled databases. But, PMON does not do any GRD
maintenance.
In 9i, LMS maintains structures related to lock messaging which is
also stored inside the GRD.
corrections are welcome.
regards,
anand
On 26/07/05, Hameed, Amir <Amir.Hameed@xxxxxxxxx> wrote:
>
>
> Hi folks,
> Per the "Oracle 9i2 RAC Concepts" manual, page 3-6, "The GCS and GES
> maintain a Global Resource Directory to record information about
>
> resources". Does anyone know what parts of GRD are specifically maintained
> by GCS and GES respectively. Also, are these the only components that
> maintain GRD or are there other processes that also participate in the
> maintenance?
>
> Any feedback will be appreciated.
>
> Thank you
> Amir
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