Eviction not working in JBossCache-1.2.4SP2

[jaikiran]

Hi,
I am trying out a simple standalone app where i, put in 50 elements in the cache at a given fqn. I have enabled EvictionPolicy and set the maxNodes as 5. However none of the nodes are getting evicted. Here's the code and the config file:

package org.myapp;

import org.jboss.cache.Fqn;
import org.jboss.cache.PropertyConfigurator;
import org.jboss.cache.TreeCache;
import org.w3c.dom.Element;



public class TestEviction {
 public static void main(String arg[])
 {
 try {
 TreeCache treeCache = new TreeCache();

 PropertyConfigurator config = new PropertyConfigurator(); // configure tree cache. Needs to be in the classpath
 config.configure(treeCache, "D:\\local-eviction-service.xml");
 treeCache.start();

 System.out.println("Eviction policy class name: " +treeCache.getEvictionPolicyClass());
 System.out.println("Revisit time: " + treeCache.getEvictionThreadWakeupIntervalSeconds());

 Fqn fqn = new Fqn("a/b/c");
 for(int i=0;i<50;i++)
 {

 System.out.println("Put#"+ (i+1));
 treeCache.put(fqn, new Integer(i), "Put#" + i);
 System.out.println("Exists fqn: " + treeCache.exists(fqn));
 System.out.println("Exists object: " + treeCache.exists(fqn,new Integer(i)));
 }

 /*
 * Check the contents of FQN
 */
 System.out.println("Contents of FQN: " + treeCache._print(fqn));

 /*
 * Just verify whether eviction policy config was picked up
 */
 Element ele = treeCache.getEvictionPolicyConfig();
 System.out.println(ele.toString());

 System.out.println("Before EXPLICITLY Calling evict of FQN, Obj 1: " + treeCache.get(fqn,new Integer("1")));
 System.out.println("Before EXPLICITLY Calling evict of FQN, Obj 48: " + treeCache.get(fqn,new Integer("48")));

 /*
 * manually evict
 */
 treeCache.evict(fqn);

 System.out.println("After EXPLICITLY Calling evict of FQN, Obj 1: " + treeCache.get(fqn,new Integer("1")));
 System.out.println("After EXPLICITLY Calling evict of FQN, Obj 48: " + treeCache.get(fqn,new Integer("48")));

 } catch (Exception e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }

 }
}

Config file:

<?xml version="1.0" encoding="UTF-8"?>

<!-- ===================================================================== -->
<!-- -->
<!-- Sample TreeCache Service Configuration -->
<!-- -->
<!-- ===================================================================== -->

<server>

 <classpath codebase="./lib" archives="jboss-cache.jar, jgroups.jar"/>


 <!-- ==================================================================== -->
 <!-- Defines TreeCache configuration -->
 <!-- ==================================================================== -->

 <mbean code="org.jboss.cache.TreeCache"
 name="jboss.cache:service=TreeCache">

 <depends>jboss:service=Naming</depends>
 <depends>jboss:service=TransactionManager</depends>

 <!--
 Configure the TransactionManager
 -->
<!-- <attribute name="TransactionManagerLookupClass">org.jboss.cache.JBossTransactionManagerLookup</attribute> -->


 <!--
 Node locking level : SERIALIZABLE
 REPEATABLE_READ (default)
 READ_COMMITTED
 READ_UNCOMMITTED
 NONE
 -->
 <attribute name="IsolationLevel">REPEATABLE_READ</attribute>

 <!--
 Valid modes are LOCAL
 REPL_ASYNC
 REPL_SYNC
 -->
 <attribute name="CacheMode">LOCAL</attribute>

 <!-- Name of cluster. Needs to be the same for all clusters, in order
 to find each other
 -->
 <attribute name="ClusterName">TreeCache-Cluster</attribute>

 <!-- JGroups protocol stack properties. Can also be a URL,
 e.g. file:/home/bela/default.xml
 <attribute name="ClusterProperties"></attribute>
 -->

 <attribute name="ClusterConfig">
 <config>
 <!-- UDP: if you have a multihomed machine,
 set the bind_addr attribute to the appropriate NIC IP address -->
 <!-- UDP: On Windows machines, because of the media sense feature
 being broken with multicast (even after disabling media sense)
 set the loopback attribute to true -->
 <UDP mcast_addr="228.1.2.3" mcast_port="48866"
 ip_ttl="64" ip_mcast="true"
 mcast_send_buf_size="150000" mcast_recv_buf_size="80000"
 ucast_send_buf_size="150000" ucast_recv_buf_size="80000"
 loopback="false"/>
 <PING timeout="2000" num_initial_members="3"
 up_thread="false" down_thread="false"/>
 <MERGE2 min_interval="10000" max_interval="20000"/>
 <FD shun="true" up_thread="true" down_thread="true"/>
 <VERIFY_SUSPECT timeout="1500"
 up_thread="false" down_thread="false"/>
 <pbcast.NAKACK gc_lag="50" retransmit_timeout="600,1200,2400,4800"
 max_xmit_size="8192" up_thread="false" down_thread="false"/>
 <UNICAST timeout="600,1200,2400" window_size="100" min_threshold="10"
 down_thread="false"/>
 <pbcast.STABLE desired_avg_gossip="20000"
 up_thread="false" down_thread="false"/>
 <FRAG frag_size="8192"
 down_thread="false" up_thread="false"/>
 <pbcast.GMS join_timeout="5000" join_retry_timeout="2000"
 shun="true" print_local_addr="true"/>
 <pbcast.STATE_TRANSFER up_thread="false" down_thread="false"/>
 </config>
 </attribute>


 <!--
 The max amount of time (in milliseconds) we wait until the
 initial state (ie. the contents of the cache) are retrieved from
 existing members in a clustered environment
 -->
 <attribute name="InitialStateRetrievalTimeout">5000</attribute>

 <!--
 Number of milliseconds to wait until all responses for a
 synchronous call have been received.
 -->
 <attribute name="SyncReplTimeout">20000</attribute>

 <!-- Max number of milliseconds to wait for a lock acquisition -->
 <attribute name="LockAcquisitionTimeout">15000</attribute>


 <!-- Name of the eviction policy class. -->
 <attribute name="EvictionPolicyClass">org.jboss.cache.eviction.LRUPolicy</attribute>
 <!-- Specific eviction policy configurations. This is LRU -->
 <attribute name="EvictionPolicyConfig">
 <config>
 <attribute name="wakeUpIntervalSeconds">2</attribute>
 <!-- Cache wide default -->
 <region name="/_default_">
 <attribute name="maxNodes">5</attribute>
 <attribute name="timeToLiveSeconds">0</attribute>
 </region>
 <region name="/a/b/c">
 <attribute name="maxNodes">5</attribute>
 <attribute name="timeToLiveSeconds">0</attribute>
 </region>
 </config>
 </attribute>
 </mbean>


</server>

Any idea why this is not working?

[jaikiran]

I even introduced a time delay in putting the objects as follows, just to try out whether eviction works. But still it does not work.

The following is just an extract from the above code, with *only* a Thread.sleep(500) introduced.

for(int i=0;i<50;i++)
 {

 Thread.sleep(500);
 System.out.println("Put#"+ (i+1));
 treeCache.put(fqn, new Integer(i), "Put#" + i);
 System.out.println("Exists fqn: " + treeCache.exists(fqn));
 System.out.println("Exists object: " + treeCache.exists(fqn,new Integer(i)));
 }

[jaikiran]

Tried a few more things and looks like eviction is working for attributes like timeToLiveSeconds and maxAgeSeconds(if at all they are specified) but NOT WORKING for maxNodes.

P.S.: While debugging LRUAlgorithm.java, observed that the following statement :

ne = (NodeEntry)recycleQueue_.poll(0);

in the prune() method *always* returns null and as a result the subsequent check for maxNodes in this method is skipped. I am not sure whether this information is going to be of any use.

[jaikiran]

Please, ignore this entire topic. Had got confused with the concept of nodes and keys. Eviction is working fine.

Sorry for the trouble

[jaikiran]

Is this behavior of Fqn correct? If yes, shouldnt this be documented through the javadocs?

[jaikiran]

Sorry, posted in the wrong topic