Since app version 1.6.1, we support incremental mode to speedup the analysis of your pull requests by only passing the changed and new files of a pull request diff to Sonar. You just have to enable "incremental mode" by configuring for which branches it should be used in the Bamboo task as follows:
We also recommend that you enable creating plan branches for pull requests, because only with this mode a full analysis will be prevented when you push a new branch to Bitbucket Server and instead be deferred until the pull request is created:
