PromQL functions

These functions are based on the Prometheus query functions. Refer to the Prometheus documentation for the full semantics. Each function entry lists its differences from Prometheus, including the uses that aren't supported yet.

Functions that take a range vector and return an instant vector.

Range vector function list
  • absent_over_time

    Returns 1 if the range vector has no elements, and nothing otherwise.

  • avg_over_time

    Returns the average value of all points in the specified time range.

  • changes

    Returns the number of times the value changed in each time series in a range vector.

  • count_over_time

    Returns the count of all values in the specified time range.

  • delta

    Calculates the difference between the first and last value of each time series in a range vector.

  • deriv

    Calculates the per-second derivative of the time series using simple linear regression.

  • first_over_time

    Returns the first value of each time series in the specified time range.

  • idelta

    Calculates the difference between the last two samples of each time series in a range vector.

  • increase

    Calculates the increase in the time series in the range vector, adjusting for counter resets.

  • irate

    Calculates the per-second instant rate of increase based on the last two data points.

  • last_over_time

    Returns the most recent value of each time series in the specified time range.

  • max_over_time

    Returns the maximum value of all points in the specified time range.

  • min_over_time

    Returns the minimum value of all points in the specified time range.

  • predict_linear

    Predicts the value of each time series t seconds after the evaluation time using simple linear regression.

  • present_over_time

    Returns 1 for every series that has at least one sample in the range.

  • quantile_over_time

    Returns the φ-quantile (0 ≤ φ ≤ 1) of the values in the specified time range.

  • rate

    Calculates the per-second average rate of increase of the time series in the range vector.

  • stddev_over_time

    Returns the population standard deviation of the values in the specified time range.

  • stdvar_over_time

    Returns the population variance of the values in the specified time range.

  • sum_over_time

    Returns the sum of all values in the specified time range.

Functions that aggregate an instant vector across series.

Aggregation function list
  • avg

    Calculates the average of the values across the input vector.

  • bottomk

    Returns k time series with the lowest values, keeping their full label set. When used with by, bottomk ranks independently within each group.

  • count

    Counts the number of elements in the input vector.

  • limit_ratio

    Returns a ratio r of the series from the input vector, keeping their full label set.

  • limitk

    Returns k arbitrary elements from the input vector, keeping their full label set. Unlike topk and bottomk, selection is not sort-based and histogram samples are included.

  • max

    Returns the maximum value across the input vector.

  • min

    Returns the minimum value across the input vector.

  • quantile

    Returns the φ-quantile (0 ≤ φ ≤ 1) of the values across the input vector.

  • stddev

    Calculates the population standard deviation across the input vector.

  • stdvar

    Calculates the population variance across the input vector.

  • sum

    Calculates the sum of the values across the input vector.

  • topk

    Returns k time series with the highest values, keeping their full label set. When used with by, topk ranks independently within each group.

Functions that operate on histogram metrics.

Histogram function list
  • histogram_avg

    Returns the arithmetic average of observations stored in a native histogram.

  • histogram_count

    Returns the count of observations stored in a native histogram.

  • histogram_fraction

    Returns the estimated fraction of observations of a classic or native histogram that fall between the provided lower and upper values.

  • histogram_quantile

    Returns the φ-quantile of a classic histogram represented by cumulative le buckets or a native (exponential) histogram.

  • histogram_sum

    Returns the sum of observations stored in a native histogram.

Mathematical, trigonometric, and rounding functions.

Math function list
  • abs

    Returns the input vector with all sample values converted to their absolute value.

  • acos

    Calculates the arccosine of all elements in the input vector.

  • acosh

    Calculates the inverse hyperbolic cosine of all elements in the input vector.

  • asin

    Calculates the arcsine of all elements in the input vector.

  • asinh

    Calculates the inverse hyperbolic sine of all elements in the input vector.

  • atan

    Calculates the arctangent of all elements in the input vector.

  • atanh

    Calculates the inverse hyperbolic tangent of all elements in the input vector.

  • ceil

    Rounds the sample values of all elements up to the nearest integer.

  • clamp

    Clamps the sample values of all elements to be within [min, max].

  • clamp_max

    Clamps the sample values of all elements to have an upper limit of max.

  • clamp_min

    Clamps the sample values of all elements to have a lower limit of min.

  • cos

    Calculates the cosine of all elements in the input vector.

  • cosh

    Calculates the hyperbolic cosine of all elements in the input vector.

  • deg

    Converts input values from radians to degrees for all elements in the input vector.

  • exp

    Calculates the exponential function for all elements in the input vector.

  • floor

    Rounds the sample values of all elements down to the nearest integer.

  • ln

    Calculates the natural logarithm for all elements in the input vector.

  • log10

    Calculates the decimal logarithm for all elements in the input vector.

  • log2

    Calculates the binary logarithm for all elements in the input vector.

  • pi

    Returns the value of pi.

  • rad

    Converts input values from degrees to radians for all elements in the input vector.

  • round

    Rounds the sample values to the nearest integer, or to the nearest multiple of the optional argument.

  • sgn

    Returns the sign of the sample values: -1 for negative, 0 for zero, and 1 for positive values.

  • sin

    Calculates the sine of all elements in the input vector.

  • sinh

    Calculates the hyperbolic sine of all elements in the input vector.

  • sqrt

    Calculates the square root of all elements in the input vector.

  • tan

    Calculates the tangent of all elements in the input vector.

  • tanh

    Calculates the hyperbolic tangent of all elements in the input vector.

Functions that extract date and time components from timestamps.

Date and time function list
  • day_of_month

    Returns the day of the month for each of the input timestamps (in UTC). Returned values are from 1 to 31.

  • day_of_week

    Returns the day of the week for each of the input timestamps (in UTC). Returned values are from 0 to 6, where 0 means Sunday.

  • day_of_year

    Returns the day of the year for each of the input timestamps (in UTC). Returned values are from 1 to 366.

  • days_in_month

    Returns the number of days in the month for each of the input timestamps (in UTC). Returned values are from 28 to 31.

  • hour

    Returns the hour of the day for each of the input timestamps (in UTC). Returned values are from 0 to 23.

  • minute

    Returns the minute of the hour for each of the input timestamps (in UTC). Returned values are from 0 to 59.

  • month

    Returns the month of the year for each of the input timestamps (in UTC). Returned values are from 1 to 12.

  • time

    Returns the number of seconds since January 1, 1970 UTC. Note that this does not actually return the current time, but the time at which the expression is being evaluated.

  • timestamp

    Returns the timestamp of each sample of the given vector as the number of seconds since January 1, 1970 UTC. It acts on float and histogram samples in the same way.

  • year

    Returns the year for each of the input timestamps (in UTC).

Functions that convert between scalars and instant vectors.

Conversion function list
  • scalar

    Returns the sample value of a single-element instant vector as a scalar. If the input vector does not have exactly one element, scalar returns NaN.

  • vector

    Returns the scalar as a vector with no labels.

Functions that derive new labels from existing label values.

Metadata function list
  • label_join

    Joins the values of the source labels src_label_1 .. src_label_N using separator and stores the result in the label dst_label. A missing source label contributes an empty string.

  • label_replace

    Matches the regular expression regex against the value of the label src_label. On a match, sets the label dst_label to the expansion of replacement, substituting $1, $name, and ${name} with the matched capture groups; on no match the input series is returned unchanged.

Functions that sort an instant vector by sample value.

Sorting function list
  • sort

    Sorts instant-vector series by sample value in ascending order. NaN values are sorted last.

  • sort_desc

    Sorts instant-vector series by sample value in descending order. NaN values are sorted last.

The following PromQL functions are recognized but not supported yet in Elasticsearch. Using them returns a client error (4xx):

  • absent
  • count_values
  • double_exponential_smoothing
  • group
  • histogram_stddev
  • histogram_stdvar
  • holt_winters
  • info
  • mad_over_time
  • resets
  • sort_by_label
  • sort_by_label_desc