On 12/9/2015 7:56 AM, Steven White wrote: > Thanks Erick!! Your summary and the blog by Uwe (thank you too Uwe) are > very helpful. > > A follow up question. I also noticed the "JVM-Memory" report off Solr's > home page is fluctuating. I expect some fluctuation, but it kinda worries > me when it fluctuates up / down in a range of 4 GB and maybe more. I.e.: > at times it is at 5 GB and other times it is at 10 GB (this is while I'm > running my search tests). What does such high fluctuation means? > > If it helps, Solr's "JVM-Memory" report states 2.5 GB usage when Solr is > first started and before I run any search on it. I'm taking this as my > base startup memory usage.
The heap usage at any particular instant in time (even right after startup) is nearly useless information. To reach any useful conclusions and change your heap size based on those conclusions, heap usage must be tracked (and ideally graphed) for several minutes or hours, sampling no less frequently than about every five or ten seconds -- exactly what programs like JConsole (included with the Java JDK) do. You will want to do the tracking/graphing during your your heaviest usage for both queries and indexing. See the "How much heap space do I need?" section here for some relatively vague pointers: https://wiki.apache.org/solr/SolrPerformanceProblems#How_much_heap_space_do_I_need.3F Thanks, Shawn
