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Introduction

The make-series operator transforms event data into array-based time series. Instead of producing one row per time bucket, make-series encodes the values and corresponding timestamps into arrays stored in table fields. This makes it possible to apply series_* functions for advanced manipulations such as moving averages, smoothing, anomaly detection, or other time-series computations. You find this operator useful when you want to:
  • Turn event data into array-encoded time series for further analysis.
  • Apply series_* functions (for example, series_fir, series_stats) to aggregated data.
  • Postprocess and then expand arrays back into rows with mv-expand for visualization or downstream queries.
Unlike summarize, which produces row-based aggregations, make-series is designed specifically for creating and manipulating array-based time series.

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For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.
In Splunk SPL, the timechart command creates row-based time series, with one row per time bucket. In APL, the make-series operator instead encodes the series into arrays, which you can later manipulate or expand. This is a key difference from SPL’s row-based approach.
index=sample-http-logs
| timechart span=1m avg(req_duration_ms)
In ANSI SQL, you typically use GROUP BY with a generated series or calendar table to create row-based time buckets. In APL, make-series creates arrays of values and timestamps in a single row. This lets you perform array-based computations on the time series before optionally expanding back into rows.
SELECT
  time_bucket('1 minute', _time) AS minute,
  AVG(req_duration_ms) AS avg_duration
FROM sample_http_logs
WHERE _time > NOW() - interval '1 hour'
GROUP BY minute
ORDER BY minute

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Usage

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Syntax

make-series [Aggregation [, ...]]
    [default = DefaultValue]
    on TimeField
    [in Range]
    step StepSize
    [by GroupingField [, ...]]

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Parameters

ParameterDescription
AggregationOne or more aggregation functions (for example, avg(), count(), sum()) applied to each time bin, producing arrays of values.
defaultA value to use when no records exist in a time bin.
TimeFieldThe field containing timestamps used for binning.
RangeAn optional range expression specifying the start and end of the series (for example, from ago(1h) to now()).
StepSizeThe size of each time bin (for example, 1m, 5m, 1h).
GroupingFieldOptional fields to split the series by, producing parallel arrays for each group.

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Returns

The operator returns a table where each aggregation produces an array of values aligned with an array of time bins. Each row represents a group (if specified), with arrays that encode the entire time series.

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Use case examples

  • Log analysis
  • OpenTelemetry traces
  • Security logs
You want to create an array-based time series of request counts, then compute a rolling average using a series_* function, and finally expand back into rows for visualization.Query
['sample-http-logs']
| make-series count() on _time from now()-24h to now() step 5m
| extend moving_avg_count=series_fir(count_, dynamic([1, 1, 1, 1, 1]))
| mv-expand moving_avg_count to typeof(long), count_ to typeof(long), time to typeof(datetime)
| project-rename _time=time
| summarize avg(moving_avg_count), avg(count_) by bin(_time, 5m)
Run in PlaygroundOutput
_timecount_moving_avg_count
2025-09-29T10:00:00120118
2025-09-29T10:05:00130122
2025-09-29T10:10:00110121
The query turns request counts into arrays, applies a smoothing function, and then expands the arrays back into rows for analysis.
  • extend: Creates new calculated fields, often as preparation before make-series. Use extend when you want to preprocess data for time series analysis.
  • mv-expand: Expands arrays into multiple rows. Use mv-expand to work with the arrays returned by make-series.
  • summarize: Aggregates rows into groups but does not generate continuous time bins. Use summarize when you want flexible grouping without forcing evenly spaced intervals.
  • top: Returns the top rows by a specified expression, not time series. Use top when you want to focus on the most significant values instead of trends over time.
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