The metric functions include functions such as mean, min and max. These values are calculated for each bucket. Field values that cannot be converted to double precision floating point numbers are ignored.
The XPack machine learning features include the following metric functions:
Min
The min
function detects anomalies in the arithmetic minimum of a value.
The minimum value is calculated for each bucket.
High and lowsided functions are not applicable.
This function supports the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 1: Analyzing minimum transactions with the min function.
{ "function" : "min", "field_name" : "amt", "by_field_name" : "product" }
If you use this min
function in a detector in your job, it detects where the
smallest transaction is lower than previously observed. You can use this
function to detect items for sale at unintentionally low prices due to data
entry mistakes. It models the minimum amount for each product over time.
Max
The max
function detects anomalies in the arithmetic maximum of a value.
The maximum value is calculated for each bucket.
High and lowsided functions are not applicable.
This function supports the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 2: Analyzing maximum response times with the max function.
{ "function" : "max", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this max
function in a detector in your job, it detects where the
longest responsetime
is longer than previously observed. You can use this
function to detect applications that have responsetime
values that are
unusually lengthy. It models the maximum responsetime
for each application
over time and detects when the longest responsetime
is unusually long compared
to previous applications.
Example 3: Two detectors with max and high_mean functions.
{ "function" : "max", "field_name" : "responsetime", "by_field_name" : "application" }, { "function" : "high_mean", "field_name" : "responsetime", "by_field_name" : "application" }
The analysis in the previous example can be performed alongside high_mean
functions by application. By combining detectors and using the same influencer
this job can detect both unusually long individual response times and average
response times for each bucket.
Median
The median
function detects anomalies in the statistical median of a value.
The median value is calculated for each bucket.
High and lowsided functions are not supported.
This function supports the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 4: Analyzing response times with the median function.
{ "function" : "median", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this median
function in a detector in your job, it models the
median responsetime
for each application over time. It detects when the median
responsetime
is unusual compared to previous responsetime
values.
Mean, High_mean, Low_mean
The mean
function detects anomalies in the arithmetic mean of a value.
The mean value is calculated for each bucket.
If you want to monitor unusually high average values, use the high_mean
function.
If you are just interested in unusually low average values, use the low_mean
function.
These functions support the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 5: Analyzing response times with the mean function.
{ "function" : "mean", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this mean
function in a detector in your job, it models the mean
responsetime
for each application over time. It detects when the mean
responsetime
is unusual compared to previous responsetime
values.
Example 6: Analyzing response times with the high_mean function.
{ "function" : "high_mean", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this high_mean
function in a detector in your job, it models the
mean responsetime
for each application over time. It detects when the mean
responsetime
is unusually high compared to previous responsetime
values.
Example 7: Analyzing response times with the low_mean function.
{ "function" : "low_mean", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this low_mean
function in a detector in your job, it models the
mean responsetime
for each application over time. It detects when the mean
responsetime
is unusually low compared to previous responsetime
values.
Metric
The metric
function combines min
, max
, and mean
functions. You can use
it as a shorthand for a combined analysis. If you do not specify a function in
a detector, this is the default function.
High and lowsided functions are not applicable. You cannot use this function
when a summary_count_field_name
is specified.
This function supports the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 8: Analyzing response times with the metric function.
{ "function" : "metric", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this metric
function in a detector in your job, it models the
mean, min, and max responsetime
for each application over time. It detects
when the mean, min, or max responsetime
is unusual compared to previous
responsetime
values.
Varp, High_varp, Low_varp
The varp
function detects anomalies in the variance of a value which is a
measure of the variability and spread in the data.
If you want to monitor unusually high variance, use the high_varp
function.
If you are just interested in unusually low variance, use the low_varp
function.
These functions support the following properties:

field_name
(required) 
by_field_name
(optional) 
over_field_name
(optional) 
partition_field_name
(optional)
For more information about those properties, see Detector Configuration Objects.
Example 9: Analyzing response times with the varp function.
{ "function" : "varp", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this varp
function in a detector in your job, it models the
variance in values of responsetime
for each application over time. It detects
when the variance in responsetime
is unusual compared to past application
behavior.
Example 10: Analyzing response times with the high_varp function.
{ "function" : "high_varp", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this high_varp
function in a detector in your job, it models the
variance in values of responsetime
for each application over time. It detects
when the variance in responsetime
is unusual compared to past application
behavior.
Example 11: Analyzing response times with the low_varp function.
{ "function" : "low_varp", "field_name" : "responsetime", "by_field_name" : "application" }
If you use this low_varp
function in a detector in your job, it models the
variance in values of responsetime
for each application over time. It detects
when the variance in responsetime
is unusual compared to past application
behavior.