On 4/14/2016 12:45 PM, Betsey Benagh wrote: > I'm running solr 6.0.0 in server mode. I have one core. I loaded about 2000 > documents in, and it was using about 54 MB of memory. No problem. Nobody was > issuing queries or doing anything else, but over the course of about 4 hours, > the memory usage had tripled to 152 MB. I shut solr down and restarted it, > and saw the memory usage back at 54 MB. Again, with no queries or anything > being executed against the core, the memory usage is creeping up - after 17 > minutes, it was up to 60 MB. I've looked at the documentation for how to > limit memory usage, but I want to understand why it's creeping up when > nothing is happening, lest it run out of memory when I limit the usage. The > machine is running CentOS 6.6, if that matters, with Java 1.8.0_65.
When you start Solr 5.0 or later directly from the download or directly after installing it with the service installer script (on *NIX platforms), Solr starts with a 512MB Java heap. You can change this if you need to -- most Solr users do need to increase the heap size to a few gigabytes. Java uses a garbage collection memory model. It's perfectly normal during the operation of a Java program, even one that is not doing anything you can see, for the memory utilization to rise up to the configured heap size. This is simply how things work in systems using a garbage collection memory model. Where exactly are you looking to find the memory utilization? In the admin UI, that number will go up over time, until one of the memory pools gets full and Java does a garbage collection, and then it will likely go down again. From the operating system point of view, the resident memory usage will increase up to a point (when the entire heap has been allocated) and probably never go back down -- but it also shouldn't go up either. Thanks, Shawn
