session_count plugin

Learn how to use the session_count plugin to calculate the session count based on the ID column over a timeline.

Calculates the session count based on the ID column over a timeline. The plugin is invoked with the evaluate operator.

Syntax

TabularExpression | evaluate session_count(IdColumn, TimelineColumn, Start, End, Bin, LookBackWindow [, dim1, dim2, …])

Parameters

NameTypeRequiredDescription
TabularExpressionstring✔️The tabular expression that serves as input.
IdColumnstring✔️The name of the column with ID values that represents user activity.
TimelineColumnstring✔️The name of the column that represents the timeline.
Startscalar✔️The start of the analysis period.
Endscalar✔️The end of the analysis period.
Binscalar✔️The session’s analysis step period.
LookBackWindowscalar✔️The session lookback period. If the ID from IdColumn appears in a time window within LookBackWindow, the session is considered to be an existing one. If the ID doesn’t appear, then the session is considered to be new.
dim1, dim2, …stringA list of the dimensions columns that slice the session count calculation.

Returns

Returns a table that has the session count values for each timeline period and for each existing dimensions combination.

Output table schema is:

TimelineColumndim1..dim_ncount_sessions
type: as of TimelineColumn......long

Examples

For this example, the data is deterministic, and we use a table with two columns:

  • Timeline: a running number from 1 to 10,000
  • Id: ID of the user from 1 to 50

Id appears at the specific Timeline slot if it’s a divider of Timeline (Timeline % Id == 0).

An event with Id==1 will appear at any Timeline slot, an event with Id==2 at every second Timeline slot, and so on.

Here are 20 lines of the data:

let _data = range Timeline from 1 to 10000 step 1
    | extend __key = 1
    | join kind=inner (range Id from 1 to 50 step 1 | extend __key=1) on __key
    | where Timeline % Id == 0
    | project Timeline, Id;
// Look on few lines of the data
_data
| order by Timeline asc, Id asc
| take 20

Output

TimelineId
11
21
22
31
33
41
42
44
51
55
61
62
63
66
71
77
81
82
84
88

Let’s define a session in next terms: session considered to be active as long as user (Id) appears at least once at a timeframe of 100 time slots, while session look-back window is 41 time slots.

The next query shows the count of active sessions according to the above definition.

let _data = range Timeline from 1 to 9999 step 1
    | extend __key = 1
    | join kind=inner (range Id from 1 to 50 step 1 | extend __key=1) on __key
    | where Timeline % Id == 0
    | project Timeline, Id;
// End of data definition
_data
| evaluate session_count(Id, Timeline, 1, 10000, 100, 41)
| render linechart

Example session count.