Performance Issue: DB Hit quicker then Cache

[huangjd]

I am using JBoss Tree Cache as a Local read-only cache, with Hibernate.

When loading items from the cache, there seems to be no performance or a negative performance then when loading items from the DB. (Loading items from the DB are faster in most cases then loading items from the cache). And with larger cached items, the performance is .5 seconds or greater.

I can't seem to understand why this is the case. Maybe someone could point me in a direction so I can look as to why and how this is happening. maybe some tools to look at the JVM etc. . .

Thanks in advance.

Here is my Config File:

<?xml version="1.0" encoding="UTF-8"?>
<server>
 <classpath codebase="./lib" archives="jboss-cache.jar, jgroups.jar" />

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

 <depends>jboss:service=Naming</depends>
 <depends>jboss:service=TransactionManager</depends>
 <attribute name="NodeLockingScheme">PESSIMISTIC</attribute>
 <attribute name="IsolationLevel">REPEATABLE_READ</attribute>
 <attribute name="CacheMode">LOCAL</attribute>
 <attribute name="UseReplQueue">false</attribute>
 <attribute name="ReplQueueInterval">0</attribute>
 <attribute name="ReplQueueMaxElements">0</attribute>
 <attribute name="LockAcquisitionTimeout">15000</attribute>
 <attribute name="EvictionPolicyConfig">
 <config>
 <attribute name="wakeUpIntervalSeconds">5</attribute>
 <!-- Cache wide default -->
 <region name="/_default_"
 policyClass="org.jboss.cache.eviction.LRUPolicy">
 <attribute name="maxNodes">10000</attribute>
 <attribute name="timeToLiveSeconds">10000</attribute>
 </region>
 </config>
 </attribute>
 <attribute name="UseRegionBasedMarshalling">false</attribute>

 </mbean>
</server>

[smarlow]

A few thoughts to share:

1. There are performance tips at http://www.hibernate.org/hib_docs/v3/reference/en/html/performance.html#performance-fetching that could be helpful.

2. As per the above link, did you set "usage" to read only?



....


3. When you say that loading items from the cache is slower, do you mean for the first time access or for subsequent access (I assume you aren't including first time access when comparing performance).

4. In terms of tools, you could enable jdbc debug or set hibernate.show_sql=true and see if the database i/o meets your expectation.

Hope this helps,
Scott

[smarlow]

Also, is your database server local or on a remote machine?