Solutions > AppInsight Applications > Understanding AppInsight for IIS > Worker Process Cache

Worker Process Cache

This resource contains monitors specific to worker process cache for the current application pool. The icons of the listed performance counters in the Statistic Name column will change color to reflect the listed counter's current state. Clicking any performance counter in the Statistic Name column will take you to the Performance Counter Details page for that performance counter.

If the value of a listed performance counter approaches or crosses the Warning threshold, a yellow band will appear for the listed counter allowing plotted values that cross the threshold to easily be visualized against the yellow band. If the value of a listed performance counter approaches or crosses the Critical threshold, a red band will appear for the listed counter allowing plotted values that cross the threshold to easily be visualized against the red band. Hovering over any time period within the chart will display detailed information about that time period in the tooltip. Hovering over a counter will give you detailed information about that performance counter.

Counter Expert Knowledge

Current File Cache Memory Usage

Description:
This displays the current number of bytes used by the user-mode file cache.

Information:
The value of this counter and the value of Web Service Cache and Maximum File Cache Memory Usage should be the same.

Possible problems:
If the values are different, this means the cache was flushed.

Remediation:
If this counter is significantly lower than Web Service Cache and Maximum File Cache Memory Usage, consider recycling the worker process because the application might have a memory leak.

Maximum File Cache Memory Usage

Description:
This displays the maximum number of bytes used by the user-mode file cache since service startup.

Information:
The value of this counter and the value of Web Service Cache and Current File Cache Memory Usage should be the same.

Possible problems:
If the values are different, this means the cache was flushed.

Remediation:
If this counter is significantly higher than Web Service Cache and Current File Cache Memory Usage, consider recycling the worker process because the application might have a memory leak.

Output Cache Current Memory Usage

Description:
This displays the current number of bytes used by the output cache.

File Cache Hits

Description:
This displays the total number of successful lookups in the user-mode file cache since service startup.

Information:
Understanding this output depends on the content. For example, if the content files cannot be cached by HTTP.sys, a high value is good

File Cache Misses Description:
This displays the total number of unsuccessful lookups in the user-mode file cache since service startup.

Information:
A file cache miss means the request for the file must go to the hard disk.

Possible problems:
File cache misses negatively impact performance and scalability. This value should be as low as possible. Also note that kernel cache hits will cause this value to be low.
Metadata Cache Hits Description:
This displays the total number of successful lookups in the user-mode metadata cache since service startup.
Metadata Cache Misses Description:
This displays the total number of unsuccessful lookups in the user-mode metadata cache since service startup.

Information:
This value should be as low as possible.
Output Cache Total Hits Description:
This displays the total number of successful lookups in the output cache since service startup.
Output Cache Total Misses Description:
This displays the total number of unsuccessful lookups in the output cache since service startup.
URI Cache Hits Description:
This displays the total number of successful lookups in the user-mode URI cache since service startup.

Information:
Understanding this output depends on the content. For example, if the content cannot be cached in the HTTP.sys response cache, the value of this counter should be as high as possible. If your content can be stored in the HTTP.sys response cache, the value of this counter should be low.
URI Cache Misses Description:
This displays the total number of unsuccessful lookups in the user-mode URI cache since service startup.

Information: A low value is preferable. The value of this counter increases when IIS cannot locate the requested content in either the HTTP.sys response cache or the IIS file cache, and must locate the requested content on the hard disk.

Possible problems:
If the value of this counter is high, IIS locates the requested content on the hard disk which could slow overall performance.

Zooming

You can have the chart show a predetermined time period of data by clicking on any one of the three Zoom buttons in the head of the Zoom column. Alternatively, you can have the chart show a specific date range by dragging the mouse over an area of the chart. The time and date displayed at the top of the resource shows the amount of data currently loaded into the chart. This can be changed by clicking Edit from within the resource.

The Value from Last Poll column shows the most recent data available for the listed statistic.