After upgrade to 2017.3, IDEA (Scala project) frequently spikes to 600+ CPU for multiple minutes



IntelliJ IDEA 2017.3.2 (Ultimate Edition)
Build #IU-173.4127.27, built on December 25, 2017
JRE: 1.8.0_152-release-1024-b8 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.13.2

After upgrade to latest 2017.3, IntelliJ frequently spikes to 600+ CPU with no obvious activity.  I think this typically happens when the editor is brought to focus after a longer period of being in the background, but I haven't isolated a good consistent repro.  At that CPU usage, the software is essentially unusable for a few minutes. Other engineers on our codebase have reported similar symptoms. 

I'm not sure what other info to provide; we are on Scala-based projects with a fairly large codebase. latest Scala plugin. The above change occurred on the same codebase where older versions of IDEA did not have this problems.


Please refer to Report at with the logs, thread dumps and the CPU snapshot attached.

See if increasing the heap size helps (Help | Edit Custom VM Options).



yep, adding heap size helped. For anyone reading, bumped from 2gb to 4gb.  So far no more symptoms.


Please sign in to leave a comment.