2.3.3 metric

The metric objects represent values that are extracted from KDR UDRs and aggregated according to the tree structure in the model. Expressions are applied on the various fields in the UDRs to calculate a value, e g a sum, average, or min/max value.

The following JSON schema describes the data format of the metric object type:

Click here to expand...

{ 
   "$schema": "http://json-schema.org/draft-04/schema#", 
   "title": "KpiMgmt Metric Schema", 
   "type": "object", 
   "minProperties": 1, 
   "additionalProperties": { 
     "$ref": "#/definitions/aggregation" 
   }, 
   "definitions": { 
     "aggregation": { 
       "type": "object", 
       "properties": { 
         "fun": { 
           "enum": [ 
             "avg", 
             "sum", 
             "count" 
           ] 
         }, 
         "expr": { 
           "type": "object", 
           "minProperties": 1, 
           "additionalProperties": { 
             "$ref": "model_expression_schema.json" 
           } 
         } 
       }, 
       "additionalProperties": false, 
       "required": [ 
         "fun", 
         "expr" 
       ] 
     } 
   } 
 }

Property Description

fun

fun must contain a string that identifies one of the following aggregation functions:

avg - This function yields the average result of the expression.
min - This function yields the minimum result of the expression.
max - This function yields the maximum result of the expression.
sum - This function yields the sum of results from expression.

expr

expr must contain an arithmetic or relational expression (or combination thereof) based on the fields in the KDR input and/or constant values.

Syntax: "<KDR.type>" : "<expression>"

The functions and operators that you can use in expressions are described below.

Conditional functions:

isSet(<field>) - Returns 1 if the field is set to a value, otherwise 0
isNotSet(<field>) - Returns 1 if the field is not set to a value, otherwise 0

Operators:

+ - Addition
- - Subtraction/negation
* - Multiplication
/ - Division

Relational operators:

= - Equal
!= - Not equal
> - Greater than
< - Less than

A relational expression or sub-expression evaluates to 1 if it is true, or 0 if it is false.

You can use parentheses to modify the order of the operations, i e apply precedence rules.

Example. Expressions

Arithmetic expression:

"expr": { 
          "kdr_record_type_a": "field2-field1", 
          "kdr_record_type_b": "field3" 
         }

Expression using conditional function:

"expr": { 
          "kdr_record_type_a": "isSet(field1)" 
         }

Relational expression:

"expr": { 
          "kdr_record_type_a": "field2<(field1+10)" 
         }

In case of division by zero, the value of the output of the expression will be positive infinity, negative infinity, or NaN (Not a Number) as defined in the JVM specification.

Example - JSON Representation

"metric": { 
     "TotalNumber": { 
        "fun": "sum", 
        "expr": { 
          "kdr_record_type_a": "isSet(field1)" 
        } 
      },     
      "TotalSuccessful": { 
        "fun": "sum", 
        "expr": { 
          "kdr_record_type_a": "field1=200" 
        } 
      }, 
       "AvgDuration": { 
        "fun": "avg", 
        "expr": { 
          "kdr_record_type_a": "field2-field1", 
          "kdr_record_type_b": "field3" 
        } 
      }     
  }

Next:

2.3.4 threshold