Hi, Here is an explanation about deprecation of https://docs.oracle.com/javase/9/gctuning/concurrent-mark-sweep-cms-collector.htm
Kind Regards, Furkan KAMACI On Tue, Nov 7, 2017 at 10:46 AM, Daniel Collins <danwcoll...@gmail.com> wrote: > Oh, blimey, have Oracle gone with Ubuntu-style numbering now? :) > > On 7 November 2017 at 08:27, Markus Jelsma <markus.jel...@openindex.io> > wrote: > > > Shawn, > > > > There won't be a Java 10, we'll get Java 18.3 instead. After 9 it is a > > guess when CMS and friends are gone. > > > > Regards, > > Markus > > > > > > > > -----Original message----- > > > From:Shawn Heisey <apa...@elyograg.org> > > > Sent: Tuesday 7th November 2017 0:24 > > > To: solr-user@lucene.apache.org > > > Subject: Re: Java 9 > > > > > > On 11/6/2017 3:07 PM, Petersen, Robert (Contr) wrote: > > > > Anyone else been noticing this this msg when starting up solr with > > java 9? (This is just an FYI and not a real question) > > > > > > > > Java HotSpot(TM) 64-Bit Server VM warning: Option UseConcMarkSweepGC > > was deprecated in version 9.0 and will likely be removed in a future > > release. > > > > Java HotSpot(TM) 64-Bit Server VM warning: Option UseParNewGC was > > deprecated in version 9.0 and will likely be removed in a future release. > > > > > > I have not tried Java 9 yet. > > > > > > Looks like G1 is now the default garbage collector. I did not know > that > > > they were deprecating CMS and ParNew ... that's a little surprising. > > > Solr's default garbage collection tuning uses those two collectors. It > > > is likely that those choices will be available in all versions of Java > > > 9. It would be very uncharacteristic for Oracle to take action on > > > removing them until version 10, possibly later. > > > > > > If it were solely up to me, I would adjust Solr's startup script to use > > > the G1 collector by default, eliminating the warnings you're seeing. > > > It's not just up to me though. Lucene documentation says to NEVER use > > > the G1 collector because they believe it to be unpredictable and have > > > the potential to cause problems. I personally have never had any > issues > > > with it. There is *one* Lucene issue mentioning problems with G1GC, > and > > > that issue is *specific* to the 32-bit JVM, which is not recommended > > > because of the limited amount of memory it can use. > > > > > > My experiments with GC tuning show the G1 collector (now default in > Java > > > 9) to have very good characteristics with Solr. I have a personal page > > > on the Solr wiki that covers those experiments. > > > > > > https://wiki.apache.org/solr/ShawnHeisey > > > > > > Thanks, > > > Shawn > > > > > > > > >
