Re: Standby database Transport Lag

From: PC <>
Date: Tue, 16 Jul 2013 00:07:42 -0700 (PDT)
Message-ID: <>


Sorry for a follow up on this very old query. But I had the exact same query. So wanted to know from you if you ever got an answer or found it yourself?


On Friday, 28 November 2008 05:34:59 UTC+5:30, wrote:
> Oracle EE with Data Guard Physical Standby configured with
> Asynchronous transport and real time apply. Platform RHEL 4 x86_64.
> How can I determine the exact lag between when a transaction is
> committed on the Primary database and when that transaction gets
> written into the Standby Redo Log on the physical standby..?
> OEM Grid has a metric called Transport Lag which seems to be related
> to this time but it always reports a Transport Lag of between 5 and 15
> seconds even when our redo generation rate is very low (200 kbits/
> sec). The primary and standby are connected via a relatively under-
> utilised gigabit network so this Lag is unnecessarily high.
> So, firstly – is the Transport Lag statistic accurate (which comes
> from select * from v$dataguard_stats where name = ‘transport lag’;)
> If not how can I accurately calculate the difference between the time
> a transaction commits on the primary and the time that transaction
> arrives on the Standby (written to the Standby Redo Log)..?
> In the Oracle published doc “Data Guard Redo Transport Network Best
> Practices 10gR2’ the author states that he has a lag of less than 2
> seconds with a redo generation rate of 2Mbytes/sec on a network with a
> latency of less than 1ms. Our network latencies are also less than
> 1ms and our redo generation rate is 1 tenth of theirs yet our
> Transport Lag is consistently between 5 and 15 seconds.
> Any ideas..?
> Thanks
Received on Tue Jul 16 2013 - 09:07:42 CEST

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