Re: ADG lag after upgrading to 12.1

Rich,

Glad you found the blog post helpful.

A lag of 20-30 seconds seems very high on the same server, with no network latency. What resource contention do you have on the server? Any CPU starvation? Slow disk?

Any chance you could provide the config? Show configuration verbose
Show database verbose “dbname”

Do you have figures for the amount of redo produced at 11.2 and 12.1 ?

Regards

Neil.
sent from my phone

On 14 Mar 2019, at 14:08, Rich J <rjoralist3_at_society.servebeer.com<mailto:rjoralist3_at_society.servebeer.com>> wrote:

Hey all,

After upgrading to 12.1.0.2 from 11.2.0.3 on our primary and ADG physical standby, I started seeing lag. The standby is on the same box, used for ad-hoc reporting. Prior to the upgrade, 99.99% of all lag was 7 seconds or less over the past 12 months. After the upgrade, it's 6 minutes.

This wasn't totally unexpected, thanks to Neil's blog post https://chandlerdba.com/2019/01/03/data-guard-unexpected-lag/ and this list. After recreating the Thread 0 standby logs to be in Thread 1 about 15 hours ago, the lag has improved dramatically, as hoped. However, I'm still regularly getting lags of 20-30 seconds, whereas in 11.2 that was a rare occasion.

This isn't a show-stopper by any means, but I want to find out why the lag is still higher than in 11.2, in case it's an indicator of a configuration issue or bug.

I'm not sure where to start looking. Any ideas?

Thanks,
Rich

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