On 9/28/2020 12:17 PM, Wei wrote:
Thanks Shawn. Looks like Java 11 is the way to go with -XX:+UseNUMA. Do you see any backward compatibility issue for Solr 8 with Java 11? Can we run Solr 8 built with JDK 8 in Java 11 JRE, or need to rebuild solr with Java 11 JDK?
I do not know of any problems running the binary release of Solr 8 (which is most likely built with the Java 8 JDK) with a newer release like Java 11 or higher.
I think Sun was really burned by such problems cropping up in the days of Java 5 and 6, and their developers have worked really hard to make sure that never happens again.
If you're running Java 11, you will need to pick a different garbage collector if you expect the NUMA flag to function. The most recent releases of Solr are defaulting to G1GC, which as previously mentioned, did not gain NUMA optimizations until Java 14.
It is not clear to me whether the NUMA optimizations will work with any collector other than Parallel until Java 14. You would need to check Java documentation carefully or ask someone involved with development of Java.
If you do see an improvement using the NUMA flag with Java 11, please let us know exactly what options Solr was started with.
Thanks, Shawn
