RE: received more blocks than served?

From: Yong Huang <>
Date: Thu, 10 Jul 2008 12:24:24 -0700 (PDT)
Message-ID: <>

[Adding back the list]

Thanks, Mark. I was only thinking of instance start, but you meant restart, while other instances continue to run. It makes a lot of sense now.

So I shutdown and restarted one instance and kept the other one running on this 2-instance RAC. The sum of served vs sum of received is different now. But I keep watching and notice that the one I just started keeps increasing its stats, particularly 'gc current blocks received' while the other instance's numbers (both stats) stay constant. The difference between served and received on *this* restarted instance keeps changing too. I can't explain this. Alls jobs or scheduler jobs are disabled. No DML or DDL is running. The only queries are mine, checking v$sysstat and gv$instance.

Yong Huang

  • "Mark W. Farnham" <> wrote:

> It is not intransit. It is that the individual instance stats are zeroed on
> each restart.
> I don't think any blocks are ever served or received from nowhere ;)
> mwf
> -----Original Message-----
> From: []
> On Behalf Of Yong Huang
> Sent: Thursday, July 10, 2008 12:31 PM
> To:
> Cc:;
> Subject: Re: received more blocks than served?
> > Date: Tue, 08 Jul 2008 11:21:32 -0600
> > From: Dan Norris <>
> > Subject: Re: received more blocks than served?
> >
> > I think Mark's suggestion about the different start times is probably the
> > culprit. Flawed logic on my part--thanks Mark for pointing it out. Guess I
> > was having a Monday :-|
> > Dan
> Dan and Mark,
> I still don't understand. That seems to say that when RAC instances are
> started
> at different times, some blocks will be received from nowhere, or (as I see
> on
> some of my RAC nodes) some blocks will be sent to nowhere. Our current
> thinking
> is the cluster-wide total count by summing on gv$ views should still be
> balanced, taking into account other stats such as lost or corrupt blocks,
> blocks converted from current to CR, which are generally very small or 0.
> There
> must be something we're missing.
> If the blocks are in transit between instances, the total count will not
> balance. But your query shows a big difference (SERVED - RECEIVED). I don't
> think we can explain that big number by blocks in transit.
> Yong Huang

Received on Thu Jul 10 2008 - 14:24:24 CDT

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