I just read that page over and it looks way out of date. I’ll raise a JIRA.
> On Feb 14, 2020, at 2:55 PM, Walter Underwood <wun...@wunderwood.org> wrote: > > Yeah, that is pretty outdated. At Netflix, I was running an 8 GB heap with > Solr 1.3. :-) > > Every GC I know about has a stop-the-world collector as a last ditch measure. > > G1GC limits the time that the world will stop. It gives up after > MaxGCPauseMillis > milliseconds and leaves the rest of the garbage uncollected. If it has 5 > seconds > worth of work to do that, it might take 10 seconds, but in 200 ms chunks. It > does > a lot of other stuff outside of the pauses to make the major collections more > effective. > > We wrote Ultraseek in Python+C because Python used reference counting and > did not do garbage collection. That is the only way to have no pauses with > automatic memory management. > > wunder > Walter Underwood > wun...@wunderwood.org > http://observer.wunderwood.org/ (my blog) > >> On Feb 14, 2020, at 11:35 AM, Tom Burton-West <tburt...@umich.edu> wrote: >> >> Hello, >> >> In the section on JVM tuning in the Solr 8.3 documentation ( >> https://lucene.apache.org/solr/guide/8_3/jvm-settings.html#jvm-settings) >> there is a paragraph which cautions about setting heap sizes over 2 GB: >> >> "The larger the heap the longer it takes to do garbage collection. This can >> mean minor, random pauses or, in extreme cases, "freeze the world" pauses >> of a minute or more. As a practical matter, this can become a serious >> problem for heap sizes that exceed about **two gigabytes**, even if far >> more physical memory is available. On robust hardware, you may get better >> results running multiple JVMs, rather than just one with a large memory >> heap. " (** added by me) >> >> I suspect this paragraph is severely outdated, but am not a Java expert. >> It seems to be contradicted by the statement in " >> https://lucene.apache.org/solr/guide/8_3/taking-solr-to-production.html#memory-and-gc-settings"; >> "...values between 10 and 20 gigabytes are not uncommon for production >> servers" >> >> Are "freeze the world" pauses still an issue with modern JVM's? >> Is it still advisable to avoid heap sizes over 2GB? >> >> Tom >> https://www.hathitrust.org/blogslarge-scale-search >
