Can anyone please describe me what is the role of CriticalExceptionCount measure in SharePoint 2010?
Couldn't understand the below line:
ResourcesPerPoint - Represents a normalization factor for this resource measure. 0 will disable.
CriticalExceptionCount is one of the resource usage limits defined for sandbox solution on SharePoint 2010 - it works by monitoring the following list of exception a solution may trigger:
The resource per point property is related to the Per Day/Per Site Collection usage limit. Basically, you can define an usage limit (expressed in resource point - default 300) for a specific site collection: when the usage exceeds its maximum allowed points all sandboxed solutions in the site collection are terminated, and no more can run for the remainder of the day. In this contest "The Resources Per Point (column) specifies how much of the resource, by default, causes an additional point to be added toward the Per Day/Per Site Collection total." (taken from MSDN). In your example the critical exception count usage limit is defined with a default Resource Per Point setting of 3. This means that after 3 critical exception the daily usage will be increased.
There is also a second parameter called "Absolute Limit". This defines how many resource usage should trigger an immediate termination of the process, no matter what the daily limit may by.
When using Sandboxed solutions in SharePoint 2010 the code runs in a separate process to isolate the "normal" environment from the sandboxed code.
Each site collection is allocated a number of points it can use for sandboxed code each day. The moment the site collection has consumed more that that number of point during a day all sandboxed code execution for that site collection is disabled until next day.
So what is a point?
A point is taxed for use of certain resources. One of these resources is Critical Exceptions others are CPU, IO,... see Resource Usage Limits on Sandboxed Solutions in SharePoint 2010 for full list. As you can't just add CPU time, IO operations, Exception count..., SharePoint has introduced a way to convert each of these into points.
For CriticalExceptionCount there is set to numbers:
The exceptions that count as Critical in this context are: