Finds the largest number for the specified field over a set of events.
Omitted Argument NamesThe argument name for
field
can be omitted; the following forms of this function are equivalent:logscale Syntax
max("value")
and:
logscale Syntax
max(field="value")
These examples show basic structure only.
max()
Syntax Examples
Return what was the maximum responsetime:
max(responsetime)
Filter for events in the repository with maximum responsetime values greater than 5 seconds:
max(responsetime)
| _max> 5
max()
Examples
Click + next to an example below to get the full details.
Alert Query for Parsers Issues
Reporting errors
Query
#type=humio #kind=logs
| loglevel=WARN
| class = c.h.d.ParserLimitingJob
| "Setting reject ingest for"
| groupBy(id, function=[count(), min(@timestamp), max(@timestamp)] )
| timeDiff:=_max-_min
| timeDiff > 300000 and _count > 10
Introduction
This alert query tries to balance reacting when there are problems with parsers, without being too restrictive.
Step-by-Step
Starting with the source repository events.
- logscale
#type=humio #kind=logs
Filters on all logs across all hosts in the cluster.
- logscale
| loglevel=WARN
Filters for all events where the loglevel is equal to
WARN
. - logscale
| class = c.h.d.ParserLimitingJob
Assigns the value
c.h.d.ParserLimitingJob
to the class for the logs having the loglevel valueWARN
. - logscale
| "Setting reject ingest for"
Filters for events containing the string
Setting reject ingest for
. This is the error message generated when ingested events are rejected. - logscale
| groupBy(id, function=[count(), min(@timestamp), max(@timestamp)] )
Groups the returned result by the field id, makes a count on the events and returns the minimum timestamp and maximum timestamp. This returns a new event set, with the fields id, _count, _min, and _max.
- logscale
| timeDiff:=_max-_min
Calculates the time difference between the maximum timestamp values and the minimum timestamp values and returns the result in a new field named timeDiff.
- logscale
| timeDiff > 300000 and _count > 10
Returns all events where the values of timeDiff is greater that
300000
and where there are more than10
occurrences. Event Result set.
Summary and Results
This query is used to set up alerts for parsers issues. Setting up alerts for parsers issues will allow to proactively reach out to customers where their queries are being throttled and help them.
Compute Aggregate Value for Each Array Element With Same Index
Compute an aggregate value for each array element with the same index using the array:reduceColumn()
Query
maxTimes := array:reduceColumn(times, var=x, function={time := max(x)})
Introduction
In this example, the array:reduceColumn()
function
is used to find the maximum time for each array element with same index
in a flat array.
Example incoming data might look like this:
times[0] | times[1] | times[2] |
---|---|---|
1 | 2 | 3 |
5 | 1 | 0 |
Step-by-Step
Starting with the source repository events.
- logscale
maxTimes := array:reduceColumn(times, var=x, function={time := max(x)})
Computes the maximum time for each array element with same index in the array and reduces it to one value.
Event Result set.
Summary and Results
The query is used to find the maximum time for each array element with same index in a flat array.
_reduceColumn[0] | _reduceColumn[1] | _reduceColumn[2] |
---|---|---|
5 | 2 | 3 |
Compute an Aggregated Value of an Array on All Events
Compute an aggregated value of a flat array on all events using the array:reduceAll()
function
Query
array:reduceAll("values[]", var=x, function=max(x))
Introduction
In this example, the aggregate function max()
is
used to output a single event with a single field.
Step-by-Step
Starting with the source repository events.
- logscale
array:reduceAll("values[]", var=x, function=max(x))
Computes the maximum value over all the values within the array values[] by using the
max()
on each element, and then across each event in the event set. Event Result set.
Summary and Results
The query is used to compute a value from all events and array elements
of a specified array. The
reduce()
method is recommended,
when you need to have a single value returned from iterating over your
array. Only aggregate functions that return a single event with a single
field (such as avg()
, count()
,
sum()
, max()
etc.) are allowed
as the function
argument.
Create a Pivot Table
Creating a view of LogScale activity
Query
groupBy([type,actor.user.id],function={groupBy(actor.user.id, function=max(@timestamp))})
|transpose(header=type)
|drop(column)
Introduction
The humio-audit repository contains audit events for the LogScale cluster. Reporting on this information can provide a wealth of information, but a useful summary can be created based on the activities, users and which the latest user of that particular operation.
Step-by-Step
Starting with the source repository events.
- logscale
groupBy([type,actor.user.id],function={groupBy(actor.user.id, function=max(@timestamp))})
The first step to creating a pivot table is the base query that will create the initial summary of the information. In this fragment, a nested
groupBy()
aggregation. The embedded aggregation creates a group of the maximum access time for a given user, by usingmax()
on the @timestamp against the actor.user.id. This creates a table of the last event by the user. The outergroupBy()
then creates an aggregation of this maximum user time against the type which defines the operation performed.The result is a table of the last user and time for a specific operation; for example, the last time a query was executed. An example of this table can be seen below:
type actor.user.id _max alert.clear-error
0O7WGPBX9YbvZbKOrBMd5fgH
1700546666592 alert.create
0O7WGPBX9YbvZbKOrBMd5fgH
1699004139419 alert.update
0O7WGPBX9YbvZbKOrBMd5fgH
1700546666676 dashboard.create
0O7WGPBX9YbvZbKOrBMd5fgH
1698417330709 dataspace.query
0O7WGPBX9YbvZbKOrBMd5fgH
1700721296197 - logscale
|transpose(header=type)
The
transpose()
will convert individual columns into rows, switching the orientation. For example, the type column will now become the type row. However, there are no row titles, so the title for the resulting table will by default create a header row containing the column and row numbers, like this:column row[1] row[2] row[3] row[4] row[5] _max 1700546666592 1699004139419 1700546666676 1698417330709 1700722209214 actor.user.id 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH type alert.clear-error alert.create alert.update dashboard.create dataspace.query However, the aggregate grouping, type could be used instead as a valid header for each column. To achieve that, use the
header
parameter to specify type as the column. The resulting table now looks like this:alert.clear-error alert.create alert.update column dashboard.create dataspace.query 1700546666592 1699004139419 1700546666676 _max 1698417330709 1700722210073 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH actor.user.id 0O7WGPBX9YbvZbKOrBMd5fgH 0O7WGPBX9YbvZbKOrBMd5fgH - logscale
|drop(column)
The table created contains the summarized information pivoted around the user ID and last event time further summarized by the type of the event. However, there is a column in the table, column, which is now a field in the event stream that was generated from the old row before the table was pivoted.
That column can be removed by dropping the column field from the event using
drop()
to remove the column from the events. Event Result set.
Summary and Results
Pivoting an event set of data allows for the information to be displayed and summarized in a format that may make more logical sense as a display format. The final table will look like this:
alert.clear-error | alert.create | alert.update | dashboard.create | dataspace.query |
---|---|---|---|---|
1700546666592 | 1699004139419 | 1700546666676 | 1698417330709 | 1700722210073 |
0O7WGPBX9YbvZbKOrBMd5fgH | 0O7WGPBX9YbvZbKOrBMd5fgH | 0O7WGPBX9YbvZbKOrBMd5fgH | 0O7WGPBX9YbvZbKOrBMd5fgH | 0O7WGPBX9YbvZbKOrBMd5fgH |
Rounding Within a Timechart
Query
timeChart(function=max(value))
| round(_max, how=floor)
Introduction
Round a field and display using a Time
chart
.
Step-by-Step
Starting with the source repository events.
- logscale
timeChart(function=max(value))
Creates a
Time Chart
usingmax()
as the aggregate function for the value field. - logscale
| round(_max, how=floor)
Rounds the implied field from the aggregate
max()
using thefloor
option to round down the value. Event Result set.
Summary and Results
Using the floor
parameter to a
function always rounds down a number. This is useful when displaying
information in a time chart as all numbers resolved to their base value
which can make the differences between values easier to distinguish when
used on a graph.