Still working on my custom external system plugin. It's starting to work pretty well now, but this problem has been annoying me. It's always sort-of been there, but sometimes just doesn't show up. Getting it regularly now.
There are a ton of messages like the following:
2020-01-23 16:52:42,720 [ 915025] INFO - penapi.project.DumbServiceImpl - cancel com.intellij.util.indexing.UnindexedFilesUpdater@2a0a9514
If it helps any, I'm seeing it log a lot of threadDump files, top places seem to be:
OrderRootsCache.disposePointers -> ObjectTree.executeAll (which creates a Throwable and calls fillInStackTrace),
ProjectFileIndexImpl.isUnderIgnored -> DirectoryIndexImpl.getRootIndex