This section covers the properties that can be used to print tables of performance statistics for the system, Wrapper process and JVM.
These statistics were added in version 3.5.52 to help understand issues in situations such as when the JVM is detected hung.
The data are subject to change in future versions of the Wrapper, but currently include memory and CPU usage.
They are collected at regular intervals by the Wrapper and then printed retrospectively when certain events occur.
This allows analysis of what happened during a given period before a problem occurred and, when included in the logs, are a useful information for technical support.
Triggering the printing of statistics:
The 'STATS' keyword can be used in the value of any action property to configure when statistics should be printed.
This feature is currently only available for Windows, but can be added to other platforms upon request.
This property can be used to enable or disable the ability to print performance statistics.
When set to FALSE, no statistics will be collected.
Statistics collection has been optimized to have a negligible impact on performance while the Wrapper is running.
In most cases it's preferred to leave the value of this property to TRUE, otherwise the information will not be available for analysis in the event of a problem.
Keep in mind that performance-related issues can be rare but are often difficult to reproduce, and the ability to consult what happened afterwards is valuable.
The default value is TRUE.
Example: Disable statistics.
This property can be used to enable or disable the ability to print performance statistics for the System.
Currently, the Physical memory, Committed memory, and Cache are included in the system statistics.
This property specifies the maximum number of lines to be printed per statistics table.
Be aware that increasing the value of this property will result in more log output.
The value can be balanced with wrapper.stats.interval to observe performance over a period of time that is right for you, while keeping a reasonable number of rows per table.
Valid values are in the range of "1" to "60".
The default value is 10.
Example: Limit to 5 lines.
This property specifies the interval, in seconds, at which statistics are collected.
The starting time and ending time of each interval can be visualized in the first column of the tables.
Valid values are in the range of "1-86400" (1 second - 1 day).
This property controls whether statistics should be printed when the Wrapper detects that the JVM is hung.
It is similar to wrapper.request_thread_dump_on_failed_jvm_exit, which causes a thread dumps in the same situation of a hung JVM.
When this property is set to TRUE, the statistics will be printed before the thread dumps (if requested), which itself happens before the JVM process is being terminated.