# server

Arivnd Ramesh

02/15/2023, 1:49 AM
Hi everyone, I apologize in advance if this is Not Kotlin, but I think it might be related so I figured I would give it a shot in this channel. I recently upgraded my app to Java 17 (from 1.8) and Kotlin 1.8.10 (from 1.6.10), and when we deployed it we saw a big spike in latency and rolled back. Using our profiling tool, I noticed that the JIT compiler was taking significantly longer in the new deployment, as was garbage collection. Has anyone run into an issue while attempting a version upgrade like this, or in general has advice on where to start troubleshooting this?

Dariusz Kuc

02/15/2023, 1:57 AM
Check your jvm config -> java 8 defaulted to parallel gc whereas for 17 it is g1
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James Richardson

02/15/2023, 8:29 AM
In general advice would be try to upgrade one thing at a time. Was there a reason to upgrade both at the same time? Was there a missed opportunity to detect this before it reaching production? Often, not always, you will get signals from test environments. Why jump so many releases at the same time? Both jvm and kotlin jumped many interim releases.
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