Thanks. I’m already familiar with adoc. https://issues.apache.org/jira/browse/SOLR-15056 <https://issues.apache.org/jira/browse/SOLR-15056>
Now I need to brush up on How To Contribute. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Dec 18, 2020, at 12:23 PM, Anshum Gupta <ans...@anshumgupta.net> wrote: > > Hi Walter, > > Thanks for taking this up. > > You can file a PR for the documentation change too as our docs are now a > part of the repo. Here's where you can find the docs: > https://github.com/apache/lucene-solr/tree/master/solr/solr-ref-guide > > > On Fri, Dec 18, 2020 at 9:26 AM Walter Underwood <wun...@wunderwood.org> > wrote: > >> Looking at the code, the CPU circuit breaker is unusable. >> >> This actually does use Unix load average >> (operatingSystemMXBean.getSystemLoadAverage()). That is a terrible idea. >> Interpreting the load average requires knowing the number of CPUs on a >> system. If I have 16 CPUs, I would probably set the limit at 16, with one >> process waiting for each CPU. >> >> Unfortunately, this implementation limits the thresholds to 0.5 to 0.95, >> because the implementer thought they were getting a CPU usage value, I >> guess. So the whole thing doesn’t work right. >> >> I’ll file a bug and submit a patch to use >> OperatingSystemMXBean.getSystemCPULoad(). How do I fix the documentation? >> >> wunder >> Walter Underwood >> wun...@wunderwood.org >> http://observer.wunderwood.org/ (my blog) >> >>> On Dec 16, 2020, at 10:41 AM, Walter Underwood <wun...@wunderwood.org> >> wrote: >>> >>> In https://lucene.apache.org/solr/guide/8_7/circuit-breakers.html < >> https://lucene.apache.org/solr/guide/8_7/circuit-breakers.html> >>> >>> URL to Wikipedia is broken, but that doesn’t matter, because that >> article is about a different metric. The Unix “load average” is the length >> of the run queue, the number of processes or threads waiting to run. That >> can go much, much higher than 1.0. In a high load system, I’ve seen it at >> 2X the number of CPUs or higher. >>> >>> Remove that link, it is misleading. >>> >>> The page should list the JMX metrics that are used for this. I’m >> guessing this uses OperatingSystemMXBean.getSystemCPULoad(). That metric >> goes from 0.0 to 1.0. >>> >>> >> https://docs.oracle.com/javase/7/docs/jre/api/management/extension/com/sun/management/OperatingSystemMXBean.html >> < >> https://docs.oracle.com/javase/7/docs/jre/api/management/extension/com/sun/management/OperatingSystemMXBean.html >>> >>> >>> I can see where the “load average” and “getSystemCPULoad” names cause >> confusion, but this should be correct in the documents. >>> >>> Which metric is used for the memory threshold? My best guess is that the >> percentage is calculated from the MemoryUsage object returned by >> MemoryMXBean.getHeapMemoryUsage(). >>> >>> >> https://docs.oracle.com/javase/7/docs/api/java/lang/management/MemoryMXBean.html >> < >> https://docs.oracle.com/javase/7/docs/api/java/lang/management/MemoryMXBean.html >>> >>> >> https://docs.oracle.com/javase/7/docs/api/java/lang/management/MemoryUsage.html >> < >> https://docs.oracle.com/javase/7/docs/api/java/lang/management/MemoryUsage.html >>> >>> >>> wunder >>> Walter Underwood >>> wun...@wunderwood.org <mailto:wun...@wunderwood.org> >>> http://observer.wunderwood.org/ (my blog) >>> >> >> > > -- > Anshum Gupta
