If tomcat error logs show up SEVERE: The web application [/pentaho] created a ThreadLocal with key of type but failed to remove it when the web application was stopped. This is very likely to be a memory leak.
Kill background process/action still running and start again.
set JAVA_OPTS="-Xms512m -Xmx1024m -XX:MaxPermSize=1024m".
(We can avoid 19Q and 20Q, as it related to internal activity)