David Hallberg

If You Rewrite the Rules…

How I love rules. By following certain clear principles, you can be reasonably sure of the outcomes. If you wash your hands regularly, then you’ll spread fewer diseases. If you listen carefully, then you’ll be better able to address a person’s concerns. In the IT world, it’s called the if-then-else logic loop. But I’m the first to admit that rules have limitations. I’ll leave you to figure out their limitations in your personal life, but this week I’ll help you determine if some of the rules you have set up in Millennium® are a bit broken.

Millennium has a wonderful subsystem called Discern EKS, which allows users to identify special events that will automatically trigger other events. For instance, users can set a rule that whenever a patient’s white blood cell count is very high, say 15,000 to 30,000, an alert suggesting a blood culture will be generated. Each department determines the rules it needs based on its standard operating procedures, works with the appropriate teams in the organization to set them up and outlines its response when the rules are triggered.

It sounds straightforward enough, and most organizations don’t give much thought to the rules if they are running in less than a second or two. Run time alone, however, does not tell the whole story. Organizations can have hundreds or thousands of rules, some of which fire thousands or tens of thousands of times a day. They can present a huge drag on the Millennium system, and these tuning issues need to be addressed.

For example, if a rule takes one second to run – which would be considered a reasonably fast rule – but is triggered 1,000 times in one day, that one rule is using up 1,000 seconds – or over 16 minutes – of application CPU time. Rules firing more than once per minute – more than 1,440 times a day – need closer scrutiny. I would recommend that you look at that rule’s trigger mechanism and verify it really should be firing that frequently.

Rules that trigger once per minute are not uncommon. I’ve worked with clients that have rules triggering more than once per second – that’s 86,400 times a day. Now consider that many sites have hundreds or thousands of these rules. Even if all of them are so-called fast rules, you can still see where you might have Millennium performance issues.

To determine if you’re having issues with a rule or set of rules, we’ll look at the Oracle table EKS_MODULE_AUDIT. This table shows when rules are triggered and how long they take to fire, along with a lot more useful information. To learn how to access the EKS audit table and analyze its numbers, click here.

Prognosis: An analysis of the time Millennium spends each day running rules will show you whether any rules need to be rewritten to help the system run faster.