Search Reference

eventstats

Description

Adds summary statistics to all search results.

Generate summary statistics of all existing fields in your search results and saves those statistics in to new fields. The eventstats command is similar to the stats command. The difference is that with the eventstats command aggregation results are added inline to each event and added only if the aggregation is pertinent to that event.

Syntax

eventstats [allnum=<bool>] <stats-agg-term>... [<by-clause>]

Required arguments

<stats-agg-term>

Syntax: <stats-func>( <evaled-field> | <wc-field> ) [AS <wc-field>]

Description: A statistical aggregation function. See Stats function options. The function can be applied to an eval expression, or to a field or set of fields. Use the AS clause to place the result into a new field with a name that you specify. You can use wild card characters in field names.

Optional arguments

allnum

Syntax: allnum=<bool>

Description: If true, computes numerical statistics on each field if and only if all of the values of that field are numerical.

Default: false

<by-clause>

Syntax: BY <field-list>

Description: The name of one or more fields to group by.

Stats function options

stats-func

Syntax: The syntax depends on the function that you use. Refer to the table below.

Description: Statistical and charting functions that you can use with the eventstats command. Each time you invoke the eventstats command, you can use one or more functions. However, you can only use one BY clause. See Usage.

The following table lists the supported functions by type of function. Use the links in the table to see descriptions and examples for each function. For an overview about using functions with commands, see Statistical and charting functions.

Type of function	Supported functions and syntax
Aggregate functions	avg() count() distinct_count() estdc() estdc_error()	exactperc<int>() max() median() min() mode()	perc<int>() range() stdev() stdevp()	sum() sumsq() upperperc<int>() var() varp()
Event order functions	earliest()	first()	last()	latest()
Multivalue stats and chart functions	list(X)	values(X)

Usage

In the limits.conf file, the max_mem_usage_mb setting in the [default] stanza is used to limit how much memory the stats and eventstats commands use to keep track of information. If the eventstats command reaches this limit, the command stops adding the requested fields to the search results. You can increase the limit, contingent on the available system memory.

Additionally, the maxresultrows setting in the [searchresults] stanza specifies the maximum number of results to return. The default value is 50,000. Increasing this limit can result in more memory usage.

Only users with file system access, such as system administrators, can edit the configuration files. Never change or copy the configuration files in the default directory. The files in the default directory must remain intact and in their original location. Make the changes in the local directory.

See How to edit a configuration file.

If you are using Splunk Cloud and want to change either of these settings, file a Support ticket.

Functions and memory usage

Some functions are inherently more expensive, from a memory standpoint, than other functions. For example, the distinct_count function requires far more memory than the count function. The values and list functions also can consume a lot of memory.

If you are using the distinct_count function without a split-by field or with a low-cardinality split-by by field, consider replacing the distinct_count function with the the estdc function (estimated distinct count). The estdc function might result in significantly lower memory usage and run times.

Event order functions

Using the first and last functions when searching based on time does not produce accurate results.

• To locate the first value based on time order, use the earliest function, instead of the first function.
• To locate the last value based on time order, use the latest function, instead of the last function.

For example, consider the following search.

index=test sourcetype=testDb | eventstats first(LastPass) as LastPass, last(_time) as mostRecentTestTime BY testCaseId | where startTime==LastPass OR _time==mostRecentTestTime | stats first(startTime) AS startTime, first(status) AS status, first(histID) AS currentHistId, last(histID) AS lastPassHistId BY testCaseId

When you use the stats and eventstats commands for ordering events based on time, use the earliest and latest functions.

The following search is the same as the previous search except the first and last functions are replaced with the earliest and latest functions.

index=test sourcetype=testDb | eventstats latest(LastPass) AS LastPass, earliest(_time) AS mostRecentTestTime BY testCaseId | where startTime==LastPass OR _time==mostRecentTestTime | stats latest(startTime) AS startTime, latest(status) AS status, latest(histID) AS currentHistId, earliest(histID) AS lastPassHistId BY testCaseId

Examples

Example 1: Compute the overall average duration and add 'avgdur' as a new field to each event where the 'duration' field exists

... | eventstats avg(duration) AS avgdur

Example 2: Same as Example 1 except that averages are calculated for each distinct value of date_hour and then each event gets the average for its particular value of date_hour.

... | eventstats avg(duration) AS avgdur BY date_hour

Example 3: This searches for spikes in error volume. You can use this search to trigger an alert if the count of errors is higher than average, for example.

eventtype="error" | eventstats avg(foo) AS avg | where foo>avg

See also

Commands

stats, streamstats

Blogs

Getting started with stats, eventstats and streamstats

Answers

Have questions? Visit Splunk Answers and see what questions and answers the Splunk community has using the eventstats command.