When last night’s Oracle/Exadata post got too long — and before I knew Oracle would request a different section be cut — I set aside my comments on Oracle’s workload management story to post separately. Elements of Oracle’s workload management story include:
- Oracle’s workload management product is called Oracle Database Resource Manager.
- Oracle Database Resource Manager has long managed CPU. For Exadata, Oracle added in management of I/O. Management of RAM is coming.
- Another aspect of Oracle workload management is “instance caging.” If you’re running multiple instances of Oracle on the same box – e.g. one with 128 cores and thus 256 threads – instance caging can keep an instance confined to a specific number of threads.
- Policies can let some classes of user get access to more threads in Oracle Parallel Query than others do.*
- Oracle offers a QoS (Quality of Service) layer, at least on Exadata, that tries to use Oracle’s workload management capabilities to enforce SLAs (Service Level Agreements). For example, if you want a certain query to always be answered in no more than 0.3 seconds, it tries to make that happen. However, this technology is new in the current Oracle release, and will be enhanced going forward.
One reason I split out this discussion of workload management is that I also talked with IBM’s Tim Vincent yesterday, who added some insight to what I already wrote last August about DB2/InfoSphere Warehouse workload management. Specifically:
- DB2/InfoSphere Warehouse workload management has multiple ways to manage use of CPU resources.
- DB2/InfoSphere Warehouse workload management doesn’t directly manage consumption of I/O or RAM resources. However, it can influence usage of I/O or RAM by:
- Limiting the number or rows read or returned.
- Adjusting priorities as to which queries get to prefetch the most records.
- DB2/InfoSphere Warehouse workload management doesn’t allow you to directly set an SLA mandating query response time. However, if query response times exceed a target SLA, DB2/InfoSphere Warehouse workload management can cause a statistics dump that might help you tune your way out of the problem.