The JDBC disk cache uses a relational database such as MySQL as a persistent store. It works with Oracle, MySQL and HSQL. The cache elements are serialized and written into a BLOB. Multiple regions can share a single table. You can define multiple, differently configured JDBC disk caches in one JCS instance. This allows you to use different tables for different cache regions.
If you want to use numerous JDBC disk cache instances that talk to the same database, you can configure them to share a connection pool. You might want to use several different tables to partition the data. Some operations, such as index building on a MyISAM storage engine take longer if there are more items in the table.