After upgrading to 22.214.171.124 from 126.96.36.199 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
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?