I have configured JBoss Cache to asynchronously write to a MySQL database. I'm using this "write-behind" configuration in order to improve performance by not blocking the client while writing to the database. However, it seems that there is still a performance hit. For example, I tested writing an object to the JBoss Cache without any persistence. This only took about 1ms. In contrast, when I configured the cache to use MySQL asynchronously, the operation took about 30ms. My cache config file looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<jbosscache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:jboss:jbosscache-core:config:3.1">
<loaders passivation="false" shared="true">
<loader class="org.jboss.cache.loader.JDBCCacheLoader" async="true"
fetchPersistentState="false" ignoreModifications="false" purgeOnStartup="false">
<properties>
cache.jdbc.table.name=jbosscache
cache.jdbc.table.create=true
cache.jdbc.table.drop=false
cache.jdbc.table.primarykey=jbosscache_pk
cache.jdbc.fqn.column=fqn
cache.jdbc.fqn.type=VARCHAR(255)
cache.jdbc.node.column=node
cache.jdbc.parent.column=parent
cache.jdbc.driver=com.mysql.jdbc.Driver
cache.jdbc.url=jdbc:mysql://${interview.db.host:localhost}:${interview.db.port:3306}/${interview.db.name:mydatabase}
cache.jdbc.user=${interview.db.username:root}
cache.jdbc.password=${interview.db.password:}
cache.jdbc.node.type=LONGBLOB
</properties>
</loader>
</loaders>
</jbosscache>Why does it take so much longer to write to a cache that asynchronously writes to a database? Shouldn't this call return immediately while running the database update in a separate thread? Is it caused by the overhead required to create and run the new thread?
Thanks!
Dustin
