Garbage collection tuning
Follow-up to Garbage collection and Hibernate performance tuning from Kieran's blog
Some of the changes I was making to the GC settings were not really making the different I thought they should be. More or less every minute on the dot, there was a full GC, which is far too often.
We had known for a while that there is a default full GC interval of 1 minute for RMI GC.
The above will set the intervals to be an hour. However…it turns out that everywhere we had it set we had "gcinterval" without the capital I :(
Change the variable to be the capital I and all of a sudden the per minute full GC's are gone! Sigh.
Analysing the throughput with the very handy GCViewer showed that it had gone from a poor 86% up to 97%, with full GC's probably only every 5 minutes or more.
Now that the stupid RMI interval problem is fixed, I should be able to more reliably tune the GC even further.