Virtual Storage Enhancements
In V8 IBM began a major project to transform DB2 into a 64-bit RDBMS. The groundwork was laid to provide some scalability improvements but a lot of DBM1 objects remained below the 2GB bar.
In the DB2 9 release things a little, but only by another 10-15% for most customers – practical limit of 300-500 threads per DB2 subsystem.
DB2 10 moves 80-90% of the remaining objects above the bar, resulting in 5-10x improvement in threads per subsystem. This is great news because less DB2 subsystems mean lower data sharing overhead and less systems to manage and maintain. We also get more space for critical storage objects such as dynamic statement cache.