michaelsembwever commented on code in PR #3696: URL: https://github.com/apache/cassandra/pull/3696#discussion_r2749589418
########## conf/jvm-server.options: ########## @@ -185,6 +185,25 @@ # For production use you may wish to adjust this for your environment. # If that's the case, see MAX_HEAP_SIZE (and HEAP_NEWSIZE for CMS) in cassandra-env.sh +# Need experimental bytebuddy for JDK21 +-Dnet.bytebuddy.experimental + +# Young generation size is automatically calculated by cassandra-env +# based on this formula: min(100 * num_cores, 1/4 * heap size) +# +# The main trade-off for the young generation is that the larger it +# is, the longer GC pause times will be. The shorter it is, the more +# expensive GC will be (usually). +# +# It is not recommended to set the young generation size if using the +# G1 GC, since that will override the target pause-time goal. +# More info: http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html +# +# The example below assumes a modern 8-core+ machine for decent +# times. If in doubt, and if you do not particularly want to tweak, go +# 100 MB per physical CPU core. +#-Xmn800M Review Comment: cassandra-env.sh already catches and informs you if you try set it. see https://github.com/jmckenzie-dev/cassandra/blob/c78641cbfa9032986beffd07faf18843cecaec79/conf/cassandra-env.sh#L161-L168 to me this doesn't help clarify, it only makes the documentation more complicated and confusing. at first glance it looks like Xmx can be set, and set here, which is wrong on both accounts. if we want to improve user feedback, then i'd rather see the above text added to https://github.com/jmckenzie-dev/cassandra/blob/c78641cbfa9032986beffd07faf18843cecaec79/conf/cassandra-env.sh#L176 (i'd also add ZGC to this check: https://github.com/jmckenzie-dev/cassandra/blob/c78641cbfa9032986beffd07faf18843cecaec79/conf/cassandra-env.sh#L171 – while Xmn doesn't crash ZGC like it does G1, we should help operators avoid applying erroneous options, when we can do from the very first time they configure and use ZGC) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
