[jboss-user] [JBossCache] - JDBCCacheLoader bad performance when writing to DB

gmeroz do-not-reply at jboss.com
Wed Jan 2 07:18:11 EST 2008


I use JDBCCacheLoader (JBossCache 2.0.0GA & Oracle in JBossAS) to persist a cahe to DB. When the cache is big it takes hours to persist.

It takes a lot of time to write the item into the DB. i loaded YourKit profiler to analyze the problem and learned that most time is spent in running SQL commands. YouKit shows that the time is spent mostly on Oracle driver's executeQuery & pingDatabase commands and that the following SQL commands are run:

1. 2600 * insert into jbosscache_table (obvious)
2. 15000 * select node from jbosscache_table where fqn=?
3. 600 * update jbosscache_table set node=? where fqn=?

i don't understand why there are 6 times more "select" statements than "insert". 

Is it related to the number of '/' in the item key?

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