Slow choppy performance navigating and editing a Groovy file in a large Grails project

When just moving around and editing many files in our project with 2017.1, there are often long pauses (2-3 seconds) where the cursor cannot be moved. Memory usage goes up and down very quickly. Even just moving the cursor around is painful. The file in question only has about 500 lines.

I've attached the CPU profiler output.

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*Imported from [IDEA-171321](https://youtrack.jetbrains.com/issue/IDEA-171321) · Type: Performance Problem · Votes: 2*
*Comments, attachments, dates and reporter are not part of the export — follow the link above for the full history.*

Start by reviewing the attached CPU profiler output and reproducing the pauses while navigating and editing a roughly 500-line Groovy file in the large Grails project. Investigate the reported cursor freezes and rapidly changing memory usage; done means navigation and editing no longer exhibit the described 2–3 second pauses.

Written by the indexing model from the issue text.