I am still using sonar-java-5.10.1 because any upgrade to sonar-java-6 ends up with 4 times longer scans.
Recently I tried SonarQube 8.9.2 LTS with sonar-java-6.15.1 with the same result.
When I replaced sonar-java-6.15.1 with sonar-java-5.10.1 in /lib/extensions directory it started to work good again. The difference is between 1,5h (old jar) and 6h (new jar).
We are using SonarQube in TeamCity, sonar scanner version : 188.8.131.528
I see that there were some problems with performance in early sonar-java-6 versions but were supposedly fixed in 6.3.
As you mentioned in your post, speed of analysis was expected to take a toll as of version 6 of the Java analyzer.
While the performance degradation has been tamed, the analyzer is still expected to be slower on version 6.3 and greater than it was on version 5.
Has there been any change in your infrastructure as you moved to SonarQube 8.9.2?
There were no changes in our infrastructure.
Should it work correctly in latest 8.9.2 release or maybe there is some configuration change that I need to do in order to have acceptable scan times ?
While we are working to enable some options to speed up the scan, I would like to share with you this post where I shared some recommendations that you can already apply now.