IntelliJ constantly indexing project

Question

I'm really impressed with the startup time of IntelliJ which is really fast, however, every time I open it when it has started its always doing this indexing which causes everything to slow down, even if previously I have gracefully closed IntelliJ, the next start it will index again, why is that?

Answer 1

IntelliJ may not be the only application using your project working directory.

If you use version control like git, SVN, or hg, or other tools such as code generators that operate on the project, then they will likely not know about IntelliJ(with or without version control-ignored IntelliJ data), and will simply write their changes.

For that reason, the IDE reindexes completion and outline data to be consistent with the code,