Erick, Can you drop a link to that Jira here after you create it?
Many thanks, Mike On Fri, Feb 14, 2020 at 6:05 PM Erick Erickson <erickerick...@gmail.com> wrote: > I just read that page over and it looks way out of date.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 Yeah, that is pretty outdated.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 I suspect this paragraph is severely outdated, but am not a Java expert.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 > > > >
