When you see memory filling up on the visualvm gui, request a heap dump. The heap dump file gets stored on the node's /tmp location. Use the eclipse memory analyzer tool (MAT) to load the downloaded ".dmp" file, the MAT analyzes the heap and generates a report of objects on the heap.
On Mon, Oct 23, 2023 at 1:48 PM Surya R <suryam...@gmail.com> wrote: > Hi. We have a solr index with around 2.5M documents , running solr 8.11 . > We have bunch of fields that we faceet/sort/highlight on. Heap is 8GB, out > of 12 GB RAM > > These fields were not defined with docValues=true due to some legacy design > issues , but if we were to rewrite the app, we would definitely have the > docvalues enabled for those fields that participate in > facet/sort/highlight. > > Problem: > I do see garbage collection ( G1GC) kicking in when the traffic is moderate > to high, with a "pause full" event that takes around 2seconds to complete. > This event happens more often when the traffic is high. > > I see this GC event happening when the humongous regions go beyond 1000. > The humongous region size is 4M > > I took a heap dump and analyzed with VisualVM, but I couldnt pinpoint what > objects are using the 'humougous region' . > > My question is, using the VisualVM, is it possible to pinpoint which / what > objects are using the 'humongous region' ? > > If for example I have an solr indexed field called "answerSnippet" , if > that is the culprit, Is it possible to see the field answerSnippet in the > VisualVM heap dump output? > > All i see is byte[] with 55% heap occupancy, but dont know what objects > constitute that byte[] > > Can anybody throw some light on this ? I really appreciate the help. > > > thanks > -- Surya >
