title: Ignite Heap Memory Usage
body: <p>I have a tomcat that does session clustering with IGNITE. I have a sample login call that creates a session for one user and after a successful login, i see the below logs that gets printed where heap size is fluctuating a lot.</p>
  
  <p>My questions are</p>
  
  <ol>
  <li><p>What does this mean. How can one single Spring session object take so much space?.</p></li>
  <li><p>Why is the whole heap size fluctuating?.</p></li>
  <li><p>Am i gonna bring down the whole server if i do 100 consecutive logins?.</p></li>
  </ol>
  
  <blockquote>
    <p>Metrics for local node (to disable set 'metricsLogFrequency' to 0)
        ^-- Node [id=fadf3af0, name=lockGrid]
        ^-- H/N/C [hosts=3, nodes=3, CPUs=6]
        ^-- CPU [cur=8.33%, avg=3.7%, GC=0.07%]
        ^-- <strong>Heap [used=261MB,</strong> free=85.03%, comm=318MB]
        ^-- Public thread pool [active=0, idle=6, qSize=0]
        ^-- System thread pool [active=0, idle=16, qSize=0]
        ^-- Outbound messages queue [size=0]
    p2016-07-29 14:12:50,205 [r-#23%lockGrid%] INFO  IgniteKernal%lockGrid   </p>
    
    <p>Metrics for local node (to disable set 'metricsLogFrequency' to 0)
        ^-- Node [id=fadf3af0, name=lockGrid]
        ^-- H/N/C [hosts=3, nodes=3, CPUs=6]
        ^-- CPU [cur=0.23%, avg=3.65%, GC=0%]
        ^-- <strong>Heap [used=402MB,</strong> free=77.01%, comm=453MB]
        ^-- Public thread pool [active=0, idle=6, qSize=0]
        ^-- System thread pool [active=0, idle=16, qSize=0]
        ^-- Outbound messages queue [size=0]
    2016-07-29 14:13:50,204 [r-#23%lockGrid%] INFO  IgniteKernal%lockGrid </p>
    
    <p>Metrics for local node (to disable set 'metricsLogFrequency' to 0)
        ^-- Node [id=fadf3af0, name=lockGrid]
        ^-- H/N/C [hosts=3, nodes=3, CPUs=6]
        ^-- CPU [cur=0.27%, avg=3.64%, GC=0%]
        ^-- Heap [used=188MB, free=89.22%, comm=363MB]
        ^-- Public thread pool [active=0, idle=6, qSize=0]
        ^-- System thread pool [active=0, idle=16, qSize=0]
        ^-- Outbound messages queue [size=0]
    2016-07-29 14:14:50,211 [r-#23%lockGrid%] INFO  IgniteKernal%lockGrid  </p>
  </blockquote>
  
  <p>Any pointers are appreciated.</p>
  
  <p>Regards,
  Aravind</p>