I have been doing some performance testing of various approaches to a persistent map. I tested HSql 1.8 (no JBoss cache yet) and found it extremely fast (1,000,000 records written and read in under 5 seconds) until I configured it for durable transactions (using statement.execute("SET WRITE_DELAY FALSE")) at which point the performance became abysmal (100,000 records took 7 minutes). An approach I have used with other implementations was to batch multiple records into a single transaction but there is no way to do that with version 1.8 of HSql. I thought JBoss Cache might be a good way to add this functionality - it does support transactions, so I might be able to use it with the jdbc driver to queue up a number of transactions into a batch. I coded this up, and could see it building a jbosshsql.script file while it ran, so I thought it might be working. Alas, the performance was on par with the straight HSql implementation with no write delay.
Here's the main bit of my setup code:
CacheFactory<K, V> factory = new DefaultCacheFactory<K, V>();
cache = factory.createCache(false);
Configuration config = cache.getConfiguration();
Configuration.CacheMode cacheMode = config.getCacheMode();
CacheLoaderConfig cacheLoaderConfig = new CacheLoaderConfig();
JDBCCacheLoaderConfig jdbcCacheLoaderConfig = new JDBCCacheLoaderConfig();
Properties properties = jdbcCacheLoaderConfig.getProperties();
jdbcCacheLoaderConfig.setJdbcURL("jdbc:hsqldb:file:" + path.getAbsolutePath());
rootNode = cache.getRoot();
transactionManager = cache.getConfiguration().getRuntimeConfig().getTransactionManager();
My thought was that I was being stupid, and that although JBoss was queueing up the records, when I committed it was still writing them to the database one at a time, but when I look at the script file that it was writing, it does look like it was trying to batch them into consolidated INSERTS:
CREATE SCHEMA PUBLIC AUTHORIZATION DBA
CREATE MEMORY TABLE JBOSSCACHE(FQN VARCHAR(255) NOT NULL PRIMARY KEY,NODE VARBINARY,PARENT VARCHAR(255))
CREATE MEMORY TABLE JBOSSCACHE_D(I CHAR)
CREATE USER SA PASSWORD ""
GRANT DBA TO SA
SET WRITE_DELAY 10
SET SCHEMA PUBLIC
INSERT INTO JBOSSCACHE VALUES('/','aced0005770700200c98bf010974000d5f746573745f69645f373939..... // This goes on and on.