Statistical and charting functions

You can use the statistical functions with the chart, stats, and timechart commands.

• Functions that you use with the stats command, can be used with the eventstats, streamstats, and geostats commands. You can also use many of these functions with the tstats command.
• Functions that you use with the chart, stats, and timechart commands can also be used with their respective summary indexing counterparts: sichart, sistats, and sitimechart.
• Functions that you can use to create sparkline charts are noted in the tables below. Sparkline is not a search command, it is a function that applies to only the chart and stats command and allows you to call other functions. For more information, see Add sparklines to search results in the Search Manual.

String and numeric field values

Most of the statistical and charting functions expect the field values to be numbers. All of the values are processed as numbers, and any non-numeric values are ignored.

Some functions process the field values as literal string values, even though the values are numbers.

count dc earliest

estdc estdc_error first

latest last list

max min mode values

For example, you use the distinct count function and the field contains values such as "1", "1.0", and "01". Each value is considered a distinct string value.

The only exceptions are the max and min functions. These functions process values as numbers if possible. For example, values such as "1", "1.0", and "01" are processed the same numeric value.

Types of functions

There are several types of statistical and charting functions:

• Aggregate functions
• Event order functions
• Multivalue functions
• Time functions

Aggregate functions

Most aggregate functions are used with numeric fields. However, there are some functions that you can use with either alphabetic string fields or numeric fields. The function descriptions indicate which functions you can use with alphabetic strings.

Function	Description	Commands	Examples
avg(X)	Returns the average of the values of field X. See also, mean(X).	chart, stats, timechart, sparkline()	This examples returns the average response time: avg(responseTime)
c(X) | count(X)	Returns the number of occurrences of the field X. To indicate a specific field value to match, format X as eval(field="value"). Processes field values as strings.	chart, stats, timechart, sparkline()	This example returns the count of events where status has the value "404": count(eval(status="404")) These generate sparklines for the counts of events. The first looks at the _raw field. The second counts events with a user field: sparkline(count) sparkline(count(user))
dc(X) | distinct_count(X)	Returns the count of distinct values of the field X. Processes field values as strings.	chart, stats, timechart, sparkline()	This example generates sparklines for the distinct count of devices and renames the field, "numdevices": sparkline(dc(device)) AS numdevices This example counts the distinct sources for each sourcetype, and buckets the count for each five minute spans: sparkline(dc(source),5m) by sourcetype
estdc(X)	Returns the estimated count of the distinct values of the field X. Processes field values as strings.	chart, stats, timechart
estdc_error(X)	Returns the theoretical error of the estimated count of the distinct values of the field X. The error represents a ratio of abs(estimate_value - real_value)/real_value. Processes field values as strings.	chart, stats, timechart
max(X)	Returns the maximum value of the field X. If the values of X are non-numeric, the max is found using lexicographical ordering. Processes field values as numbers if possible, otherwise processes field values as strings.	chart, stats, timechart, sparkline()	This example returns the maximum value of "size": max(size)
mean(X)	Returns the arithmetic mean of the field X. See also, avg(X).	chart, stats, timechart, sparkline()	This example returns the mean of "kbps" values: mean(kbps)
median(X)	Returns the middle-most value of the field X. Note: The median calculation is more accurate with an odd numbers of events. If you have an even number of events, the median is approximated to the higher of the two values.	chart, stats, timechart
min(X)	Returns the minimum value of the field X. If the values of X are non-numeric, the min is found from lexicographic ordering. Processes field values as numbers if possible, otherwise processes field values as strings.	chart, stats, timechart
mode(X)	Returns the most frequent value of the field X. Processes field values as strings.	chart, stats, timechart
p<X>(Y) | perc<X>(Y), upperperc<X>(Y), exactperc<X>(Y)	Returns the X-th percentile value of the numeric field Y, where X is an integer between 1 and 99. The percentile X-th function sorts the values of Y in an increasing order. Then, if you consider that 0% is the lowest and 100% the highest, the functions picks the value that corresponds to the position of the X% value. The functions perc (or the abbreviation p) and upperperc give approximate values for the integer percentile requested. The approximation algorithm that is used, which is based on dynamic compression of a radix tree, provides a strict bound of the actual value for any percentile. The function perc (or p) return a single number that represents the lower end of that range. The function upperperc gives the approximate upper bound. The exactperc function provides the exact value, but will be very expensive for high cardinality fields. The exactperc function could consume a large amount of memory in the search head.	chart, stats, timechart	For the list of values Y = {10,9,8,7,6,5,4,3,2,1}: perc50(Y)=6 perc95(Y)=10
range(X)	Returns the difference between the max and min values of the field X ONLY IF the value of X are numeric.	chart, stats, timechart, sparkline()
stdev(X)	Returns the sample standard deviation of the field X.	chart, stats, timechart, sparkline()	This example returns the standard deviation of wildcarded fields "*delay" which can apply to both, "delay" and "xdelay". stdev(*delay)
stdevp(X)	Returns the population standard deviation of the field X.	chart, stats, timechart, sparkline()
sum(X)	Returns the sum of the values of the field X.	chart, stats, timechart, sparkline()	sum(eval(date_hour * date_minute))
sumsq(X)	Returns the sum of the squares of the values of the field X.	chart, stats, timechart, sparkline()
var(X)	Returns the sample variance of the field X.	chart, stats, timechart, sparkline()
varp(X)	Returns the population variance of the field X.	chart, stats, timechart, sparkline()

Event order functions

These functions return events based on chronological or timestamp order.

Function	Description	Commands	Examples
earliest(X)	Returns the chronologically earliest seen occurrence of a value of a field X. Processes field values as strings.	chart, stats, timechart
first(X)	Returns the first seen value of the field X. In general, the first seen value of the field is the most recent instance of this field, relative to the input order of events into the stats command. To locate the first value based on time order, use the earliest function. Works best when the search includes the sort command immediately before the statistics or charting command. Processes field values as strings.	chart, stats, timechart
last(X)	Returns the last seen value of the field X. In general, the last seen value of the field is the oldest instance of this field relative to the input order of events into the stats command. To locate the last value based on time order, use the latest function. Works best when the search includes the sort command immediately before the statistics or charting command. Processes field values as strings.	chart, stats, timechart
latest(X)	Returns the chronologically latest seen occurrence of a value of a field X. Processes field values as strings.	chart, stats, timechart

Multivalue functions

Function	Description	Commands	Examples
list(X)	Returns a list of up to 100 values of the field X as a multivalue entry. The order of the values reflects the order of input events. if more than 100 values are in field X, only the first 100 are returned. This function processes field values as strings.	chart, stats, timechart
values(X)	Returns the list of all distinct values of the field X as a multivalue entry. The order of the values is lexicographical. By default there is no limit to the number of values returned. Users with the appropriate permissions can specify a limit in the limits.conf file. You specify the limit in the [stats | sistats] stanza using the maxvalues attribute. This function processes field values as strings.	chart, stats, timechart

Time functions

The time functions are used only with the timechart command.

Function	Description	Commands	Examples
per_day(X)	Returns the values of field X per day.	timechart	This example returns the values of "total" per day. per_day(total)
per_hour(X)	Returns the values of field X per hour.	timechart	This example returns the values of "total" per hour. per_hour(total)
per_minute(X)	Returns the values of field X per minute.	timechart	This example returns the values of "total" per minute. per_minute(total)
per_second(X)	Returns the values of field X per second.	timechart	This example returns values of "kb" per second: per_second(kb)

See also

Evaluation functions, stats, chart, timechart, eventstats, streamstats, geostats

Answers

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