Áú»¢¶Ä²©

FIXME This page is not fully translated, yet. Please help completing the translation.
(remove this paragraph once the translation is finished)

1 Aggregate functions

All functions listed here are supported in:

Aggregate functions can work with either:

  • history of items, for example, min(/host/key,1h)
  • foreach functions as the only parameter, for example, min(last_foreach(/*/key))

Some general notes on function parameters:

  • Function parameters are separated by a comma
  • Optional function parameters (or parameter parts) are indicated by < >
  • /host/key is a common mandatory first parameter for the functions referencing the host item history
  • /host/key and time period:time shift parameters must never be quoted
  • Function-specific parameters are described with each function

Aggregate functions

FUNCTION
Description Function-specific parameters Comments
avg (/host/key,time period<:time shift>)
Average value of an item within the defined evaluation period. time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Examples:
=> avg(/host/key,1h) ¡ú average value1 for an hour
=> avg(/host/key,1h:now-1d) ¡ú average value for an hour one day ago
=> avg(/host/key,#5) ¡ú average value of the five latest values

Time shift is useful when there is a need to compare the current average value with the average value some time ago.
kurtosis (/host/key,time period<:time shift>)
"Tailedness" of the probability distribution in collected values within the defined evaluation period.

See also:
time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> kurtosis(/host/key,1h) ¡ú kurtosis1 for an hour
mad (/host/key,time period<:time shift>)
Median absolute deviation in collected values within the defined evaluation period.

See also:
time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> mad(/host/key,1h) ¡ú median absolute deviation1 for an hour
max (/host/key,time period<:time shift>)
Highest value of an item within the defined evaluation period. time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> max(/host/key,1h) - min(/host/key,1h) ¡ú calculate the difference between the maximum and minimum values within the last hour1 (delta of values)
min (/host/key,time period<:time shift>)
Lowest value of an item within the defined evaluation period. time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> max(/host/key,1h) - min(/host/key,1h) ¡ú calculate the difference between the maximum and minimum values within the last hour1 (delta of values)
skewness (/host/key,time period<:time shift>)
Asymmetry of the probability distribution in collected values within the defined evaluation period.

See also:
time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> skewness(/host/key,1h) ¡ú skewness1 for an hour
stddevpop (/host/key,time period<:time shift>)
Population standard deviation in collected values within the defined evaluation period.

See also:
time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> stddevpop(/host/key,1h) ¡ú population standard deviation1 for an hour
stddevsamp (/host/key,time period<:time shift>)
Sample standard deviation in collected values within the defined evaluation period.

See also:
time period - maximum evaluation period in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

At least two data values are required for this function to work.

Example:
=> stddevsamp(/host/key,1h) ¡ú sample standard deviation1 for an hour
sum (/host/key,time period<:time shift>)
Sum of collected values within the defined evaluation period. time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> sum(/host/key,1h) ¡ú sum of values1 for an hour
sumofsquares (/host/key,time period<:time shift>)
The sum of squares in collected values within the defined evaluation period. time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> sumofsquares(/host/key,1h) ¡ú sum of squares1 for an hour
varpop (/host/key,time period<:time shift>)
Population variance of collected values within the defined evaluation period.

See also:
time period - maximum evaluation period1 in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

Example:
=> varpop(/host/key,1h) ¡ú population variance1 for an hour
varsamp (/host/key,time period<:time shift>)
Sample variance of collected values within the defined evaluation period.

See also:
time period - maximum evaluation period in seconds (time suffixes can be used) or in latest collected values (if preceded by a hash mark)

Time shift (optional) allows to move the evaluation point back in time.
Supported value types: float, int

At least two data values are required for this function to work.

Example:
=> varsamp(/host/key,1h) ¡ú sample variance1 for an hour
Footnotes

1 The function is evaluated starting with the first received value (unless the time shift parameter is used), i.e. Áú»¢¶Ä²© will not wait for all the values of the defined evaluation period before evaluating the function.