Cache the database content in memory to increase performance

Question

I have a message driven bean running on Glassfish. It receives hundreds of messages per second. After receiving a message, it needs to read the values in the JDBC database and process.

However, the values in database will only be updated one time a day or less. So what the MDB will read is consistent most of the time. So, is it there a good way to cache the content into the memory in order to increase the performance?

Update: is it posible to configure a in-memory database JDBC Connection Pool in Glassfish for the MDB?

Answer 1

The most obvious answer is to define the table as a MEMORY table type. If the underlying hardware is not prone to crashing and the OS is stable and there's a UPS attached, you might want to think about this. It also depends on the consequences of losing a number of transactions since the last backup whenever this fails. But performance-wise, this is lightning fast. More information can be found here for MySQL. (YMMV)

I've implemented multiple tables that way, and it worked great for me.

Answer 2

You can use a simple SoftReference HashMap based cache. Here is the complete implementation example SoftReference Cache In addition you can clear the complete Map periodically to bring in fresh data.
Or in case you can use 3rd party library, you might use ReferenceMap provided as part of Apache Collections.

Answer 3

You may get inspired by the identity map pattern and implement your own cache mechanism (with your own expiration policy), if you think that using a third party solution (like memcached) would be overkill.