Understanding Server Status Threshold Values
Windchill defines a set of threshold values that are used in conjunction with the Server Status page.
When your system reaches one of the thresholds, the color of the corresponding value on the page becomes red. When a threshold is reached, investigate whether there is a system issue that needs to be addressed or whether the threshold value is set too low. If you need help in determining what action to take, contact PTC Technical Support.
The threshold values are stored as attribute values in JMX MBeans and are subject to change as PTC obtains additional information about how Windchill is performing in customer environments. Additionally, you can change a threshold value to better reflect how your system is functioning.
Use the following steps to review and adjust threshold values:
1. View current default threshold values by navigating to the attribute holding the threshold values using a JMX client. The attributes are described later in this topic.
2. Adjust any threshold values that you have found do not reflect normal thresholds for your system.
3. Save changes using the Loader MBean.
4. In a cluster environment, copy changes to other nodes in the cluster.
Modifying and saving most threshold values using the Loader MBean causes a change to a specific file in the <Windchill>/codebase/WEB-INF directory, which can then be copied to other nodes.
The following list provides the Server Status page field names for which there are thresholds. Under each field, there is a description of what is being calculated, the JMX MBean tree path and attribute where the threshold is stored, and what the initial default threshold value is.
Time In Garbage Collection
Description: Calculates the garbage collection percentage for the specific process under which the link resides. This calculation only considers garbage collectors that operate on the “old gen” portion of the heap. The recent garbage collection percentage is calculated by averaging the time spent in garbage collection using a data point gathered at the specified time interval and the data point obtained at that moment the recent request is made.
Tracking this percentage is done because this portion of garbage collection is most likely to cause system problems.
MBean tree path: com.ptc > Monitors > GarbageCollection
Threshold Attribute: PercentTimeSpentInGCThreshold
Interval Attribute for recent value: RecentIntervalSeconds
Initial Default Threshold: 15% over a duration of 150 seconds
CPU Used by Process
Description: Calculates the CPU processing time percentage for the specific process (server manager or method server). The recent CPU processing time percentage is calculated by averaging the CPU processing time data point gathered at the specified time interval and the data point obtained at that moment the recent request is made.
MBean tree path: com.ptc > Monitors > ProcessCpuTime
Threshold Attribute: ProcessPercentCPUThreshold
Interval Attribute for recent value: RecentIntervalSeconds
Initial Default Threshold: 90% over a duration of 90 seconds
Memory In Use: Heap
Description: Calculates the heap memory usage percentage by the Java virtual memory (JVM) of a specific process (server manager or method server). The percentage is calculated using the current memory usage over the total memory available. There is no interval averaging being done for this data point. Notifications are sent on 30 second intervals (by default) when the threshold has been reached.
When the threshold for this calculation is exceeded, the JVM will most likely run out of memory.
MBean tree path: com.ptc > Monitors > Memory
Threshold Attribute: OldGenPercentCollUsageThreshold
Interval Attribute: CheckIntervalSeconds
Initial Default Threshold: 97.5%
Method Contexts: Maximum Concurrency
Description: Calculates the maximum number of active method contexts running in the method server JVM at any instance since the beginning of the most recent interval (Recent column) or the last baseline (Baseline column). Method contexts are the threads created to perform method server work.
When this threshold is reached, the response time for those waiting threads is usually slower.
MBean tree path: com.ptc > Monitors > MethodContexts
Threshold Attribute: MaxAverageActiveContextsThreshold
Interval Attribute for recent value: RecentIntervalSeconds; initial default interval is 60 seconds
Initial Default Threshold: (5*maxDbConnections) / 2, where maxDbConnections is the value set in the db.properties wt.pom.maxDbConnections property.
Servlet Requests: Active Sessions
Description: Calculates how many sessions are active within the Windchill web application. Since active sessions do not change that frequently, no interval is used for this calculation.
Although reaching the threshold usually means there is too much activity being routed to the JVM, you should check other indicators, to determine if there are other problems. It is possible that there is just an unexpectedly high number of concurrent users or that some custom client code is creating a separate servlet session for each request to Windchill.
MBean tree path: com.ptc > WebAppContexts > windchillWebAppPath > Monitors > ServletSessions
Threshold Attribute: MaxAverageActiveSessionsThreshold
Initial Default Threshold: 200
Servlet Requests: Maximum Concurrency
Description: Calculates how many servlet requests are current within a specific web application. Since servlet requests do not change that frequently, no interval is used for this calculation.
Although reaching the threshold can indicate that there is a Tomcat JVM issue, you should check other indicators, such as excessive memory and CPU usage, to determine if there are other problems.
MBean tree path: com.ptc > WebAppContexts > webAppContext > Monitors > ServletRequests
The web application identified by webAppContext corresponds to one of the following:
◦ For Servlet Requests: General servlet requests, select the Windchill web application.
◦ For Servlet Requests: Help Center servlet requests, select the Windchill Help Center web application.
◦ For Servlet Requests: Solr servlet requests, select the Windchill Index Search web application.
Threshold Attribute: MaxAverageActiveRequestsThreshold
Initial Default Threshold: 45