Hi, Because you went over 31-32 GB heap you lost the benefit of compressed pointers and even though you gave the JVM more memory the GC may have had to work harder. This is a relatively well educated guess, which you can confirm if you run tests and look at GC counts, times, JVM heap memory pool utilization, etc.
Otis -- Monitoring * Alerting * Anomaly Detection * Centralized Log Management Solr & Elasticsearch Support * http://sematext.com/ On Fri, Apr 17, 2015 at 10:14 PM, Kamal Kishore Aggarwal < kkroyal....@gmail.com> wrote: > Hi, > > As per this article, the linux machine is preferred to have 1.5 times RAM > with respect to index size. So, to verify this, I tried testing the solr > performance in different volumes of RAM allocation keeping other > configuration (i.e Solid State Drives, 8 core processor, 64-Bit) to be same > in both the cases. I am using solr 4.8.1 with tomcat server. > > https://wiki.apache.org/solr/SolrPerformanceProblems > > 1) Initially, the linux machine had 32 GB RAM, out of which I allocated > 14GB to solr. > > export CATALINA_OPTS="-Xms2048m -Xmx14336m -XX:+UseConcMarkSweepGC > -XX:+PrintGCApplicationStoppedTime -XX:+PrintGCDetails > -XX:+PrintGCTimeStamps -Xloggc:./logs/info_error/tomcat_gcdetails.log" > > The average search time for 1000 queries 300ms. > > 2) After that, RAM was increased to 68 GB, out of which I allocated 40GB to > Solr. Now, on a strange note, the average search time for the same set of > queries was 3000ms. > > Now, after this, I reduced solr allocated RAM to 25GB on 68GB machine. But, > still the search time was higher as compared to first case. > > What am I missing. Please suggest. >
