Typical classifications include intrusive/unintrusive, I/O-intensive, and CPU-intensive. For example, identify each object as intrusive or unintrusive, I/O intensive or not, and CPU intensive or not. You will probably need to identify additional issues specific to the environment to gain useful insight.
Two or more execution objects running on the same Adaptive Server are intrusive when they use or access a common set of resources.
Intrusive applications |
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Effect of assigning attributes |
Assigning high execution attributes to intrusive applications might degrade performance. |
Example |
Consider a situation in which a noncritical application is ready to release a resource, but becomes blocked when a highly-critical application starts executing. If a second critical application needs to use the blocked resource, then execution of this second critical application is also blocked |
If the applications in the Adaptive Server environment use different resources, they are unintrusive.
Unintrusive applications |
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Effect of assigning attributes |
You can expect enhanced performance when you assign preferred execution attributes to an unintrusive application. |
Example |
Simultaneous distinct operations on tables in different databases are unintrusive. Two operations are also unintrusive if one is compute bound and the other is I/O bound. |
When an execution object is I/O intensive, it might help to give it EC1 attributes and, at the same time, assign EC3 attributes to any compute-bound execution objects. This can help because an object performing I/O will not normally use an entire time quantum, and will give up the CPU before waiting for I/O to complete.
By giving preference to I/O-bound Adaptive Server tasks, Adaptive Server ensures that these tasks are runnable as soon as the I/O is finished. By letting the I/O take place first, the CPU should be able to accommodate both types of applications and logins.
