Collects a set of values from one or more fields. The collect() function outputs these values in two possible formats: either as a single concatenated string, or as multiple rows with individual values.

The sequence of output values is undefined and does not follow any specific order.

The collect() function operates under two collection restrictions: A maximum number of values and a maximum memory allocation.

The limit parameter defines the maximum number of values that can be collected.

The memory limit depends on where the function is used: 10 MiB if collect() is run as a top level function and 1 MiB for all other contexts.

When the collect() function exceeds either limitation, it returns partial results and displays a warning message that explains the situation.

ParameterTypeRequiredDefault ValueDescription
fields[a]array of stringsrequired   Names of the fields to collect values for.
limitintegeroptional[b] 2000 Limit to number of distinct values to collect.
  Minimum1 
multivalbooleanoptional[b] true Whether to output values as a concatenation.
   Values
   falseOutput as multiple rows containing individual values
   trueOutput as a single concatenated string
separatorstringoptional[b] \n Separator used when concatenating values (when multival=true).

[a] The parameter name fields can be omitted.

[b] Optional parameters use their default value unless explicitly set.

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collect() Function Operation

The collect() function is limited in the memory for while collecting data before the data is aggregated. The limit changes depending on whether collect() runs as a top level function — in which case its limit is 10 MiB:

logscale
#type = humio #kind=logs
| collect(myField)

or whether it runs in a subquery, or as a sub-aggregator to another function — in which case its limit is 1 MiB:

logscale
#type=humio #kind=logs
groupBy(myField, function=collect(myOtherField))

Warning

Collecting the @timestamp field currently only works when a single timestamp exists. You can work around this restriction by renaming or making another field and collecting that instead, for example:

logscale
timestamp := @timestamp
| collect(timestamp)

If you do not need more than a single value, consider using the selectLast() function or setting limit=1, if you experience that the @timestamp field not having a value.

collect() Examples

Click + next to an example below to get the full details.

Collect and Group Events by Specified Field - Example 1

Collect and group events by specified field using collect() as part of a groupBy() operation

Query
logscale
groupBy(client_ip, function=session(maxpause=1m, collect([url])))
Introduction

In this example, the collect() function is used to collect visitors, each visitor defined as non-active after one minute.

Step-by-Step

  1. Starting with the source repository events.

  2. logscale
    groupBy(client_ip, function=session(maxpause=1m, collect([url])))

    Collects visitors (URLs), each visitor defined as non-active after one minute and returns the results in an array named client_ip. A count of the events is returned in a _count field.

  3. Event Result set.

Summary and Results

The query is used to collect fields from multiple events into one event. This query analyzes user behavior by grouping events into sessions for each unique client IP address. It then collects all URLs accessed during each session. Collecting should be used on smaller data sets to create a list (or set, or map, or whatever) when you actually need a list object explicitly (for example, in order to pass it on to some other API). This analysis is valuable for understanding user engagement, and identifying potential security issues based on unusual browsing patterns. Using collect() on larger data set may cause out of memory as it returns the entire data set.

Collect and Group Events by Specified Field - Example 2

Collect and group events by specified field using collect() as part of a groupBy() operation

Query
logscale
LocalAddressIP4 = * RemoteAddressIP4 = * aip = *
| groupBy([LocalAddressIP4, RemoteAddressIP4], function=([count(aip, as=aipCount, distinct=true), collect([aip])]))
Introduction

In this example, the collect() function is used to collect fields from multiple events.

Step-by-Step

  1. Starting with the source repository events.

  2. logscale
    LocalAddressIP4 = * RemoteAddressIP4 = * aip = *

    Filters for all events where the fields LocalAddressIP4, RemoteAddressIP4 and aip are all present. The actual values in these fields do not matter; the query just checks for their existence.

  3. logscale
    | groupBy([LocalAddressIP4, RemoteAddressIP4], function=([count(aip, as=aipCount, distinct=true), collect([aip])]))

    Groups the returned results in arrays named LocalAddressIP4 and RemoteAddressIP4, collects all the AIPs (Adaptive Internet Protocol) into an array and performs a count on the field aip. The count of the AIP values is returned in a new field named aipCount.

  4. Event Result set.

Summary and Results

The query is used to collect fields from multiple events into one event. Collecting should be used on smaller data sets to create a list (or set, or map, or whatever) when you actually need a list object explicitly (for example, in order to pass it on to some other API). Using collect() on larger data set may cause out of memory as it returns the entire data set. The query is useful for network connection analysis and for identifying potential threats.

Sample output might look like this:

LocalAddressIP4RemoteAddressIP4aipCountaip
192.168.1.100203.0.113.503[10.0.0.1, 10.0.0.2, 10.0.0.3]
10.0.0.5198.51.100.751[172.16.0.1]
172.16.0.108.8.8.85[192.0.2.1, 192.0.2.2, 192.0.2.3, 192.0.2.4, 192.0.2.5]