It's a waste to set heap to 30g if your use of Solr only requires 6g to function. That is 24G memory not being used for index caching, and it will may, depending on chose GC, cause bigger/longer GC events as more garbage piles up before collection.
You have to measure and experiment to find your heap sweetspot. It is a common misconception that giving more heap to Solr improves performance of something, it's rather the contrary. Only rarely do you need huge internal solr caches, and if you find yourself needing that kind of memory due to requesting huge number of docs or faceting on high cardinality long string fields or whatever, then it is better to optimize your use of Solr to lower the footprint than to add >30g. Jan > 9. mar. 2023 kl. 12:52 skrev Dave <hastings.recurs...@gmail.com>: > > Again, set to less than 32, I liked 30 > >> On Mar 9, 2023, at 1:04 AM, Deepak Goel <deic...@gmail.com> wrote: >> >> The max heap could be the max heap used by the process uptill now. And not >> the max value you have set. I would suggest you increase the load by at >> least 20 times to see the max heap to go to 32 gb. >> >> >> Deepak >> "The greatness of a nation can be judged by the way its animals are treated >> - Mahatma Gandhi" >> >> +91 73500 12833 >> deic...@gmail.com >> >> Facebook: https://www.facebook.com/deicool >> LinkedIn: www.linkedin.com/in/deicool >> >> "Plant a Tree, Go Green" >> >> Make In India : http://www.makeinindia.com/home >> >> >>> On Thu, Mar 9, 2023 at 8:21 AM Shawn Heisey <apa...@elyograg.org> wrote: >>> >>>> On 3/8/2023 9:24 AM, HariBabu kuruva wrote: >>>> I have set the Heap memory as -Xms 1g -Xmx 40g in the Production >>>> environment. >>>> >>>> But when i see the Heap memory in the Solr UI. I can see the Max Heap >>> below. >>>> >>>> Max: 3.8Gb >>>> Used: 2.2Gb >>> >>> The other answers you've gotten are good. This is mostly just a little >>> more detail. >>> >>> If you really do have the spaces before the 1g and 40g, then those >>> values are probably not being honored as Jan said. >>> >>> If you don't have the spaces, then Java will start with the heap size at >>> 1GB, and only increase it if there is enough memory pressure. One thing >>> that I don't know is whether Java will use the 32 bit pointers with the >>> Xmx at 40g. It probably won't, so I expect that memory usage would be >>> more efficient if you set the max heap to 31g. >>> >>> With a heap size at 32GB or larger, Java has to use 64 bit pointers, and >>> that will make it use quite a bit more memory because Solr creates a LOT >>> of objects. >>> >>> As Dave said, if you use Xms and Xmx, then they should be set to the >>> same value. And the value should be less than 32GB for efficiency. >>> >>> If you use the SOLR_HEAP environment variable in the include script, >>> then both Xms and Xmx will be set to the provided value. >>> >>> Thanks, >>> Shawn >>>
