|
| 1 | +--- |
| 2 | +title: make-series |
| 3 | +description: 'This page explains how to use the make-series operator in APL.' |
| 4 | +--- |
| 5 | + |
| 6 | +## Introduction |
| 7 | + |
| 8 | +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. |
| 9 | + |
| 10 | +You find this operator useful when you want to: |
| 11 | + |
| 12 | +- Turn event data into array-encoded time series for further analysis. |
| 13 | +- Apply `series_*` functions (for example, `series_fir`, `series_stats`) to aggregated data. |
| 14 | +- Postprocess and then expand arrays back into rows with `mv-expand` for visualization or downstream queries. |
| 15 | + |
| 16 | +Unlike `summarize`, which produces row-based aggregations, `make-series` is designed specifically for creating and manipulating array-based time series. |
| 17 | + |
| 18 | +## For users of other query languages |
| 19 | + |
| 20 | +If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL. |
| 21 | + |
| 22 | +<AccordionGroup> |
| 23 | +<Accordion title="Splunk SPL users"> |
| 24 | + |
| 25 | +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. |
| 26 | + |
| 27 | +<CodeGroup> |
| 28 | +```sql Splunk example |
| 29 | +index=sample-http-logs |
| 30 | +| timechart span=1m avg(req_duration_ms) |
| 31 | +```` |
| 32 | + |
| 33 | +```kusto APL equivalent |
| 34 | +['sample-http-logs'] |
| 35 | +| make-series avg(req_duration_ms) default=0 on _time from ago(1h) to now() step 1m |
| 36 | +``` |
| 37 | + |
| 38 | +</CodeGroup> |
| 39 | + |
| 40 | +</Accordion> |
| 41 | +<Accordion title="ANSI SQL users"> |
| 42 | + |
| 43 | +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. |
| 44 | + |
| 45 | +<CodeGroup> |
| 46 | +```sql SQL example |
| 47 | +SELECT |
| 48 | + time_bucket('1 minute', _time) AS minute, |
| 49 | + AVG(req_duration_ms) AS avg_duration |
| 50 | +FROM sample_http_logs |
| 51 | +WHERE _time > NOW() - interval '1 hour' |
| 52 | +GROUP BY minute |
| 53 | +ORDER BY minute |
| 54 | +``` |
| 55 | + |
| 56 | +```kusto APL equivalent |
| 57 | +['sample-http-logs'] |
| 58 | +| make-series avg(req_duration_ms) default=0 on _time from ago(1h) to now() step 1m |
| 59 | +``` |
| 60 | + |
| 61 | +</CodeGroup> |
| 62 | + |
| 63 | +</Accordion> |
| 64 | +</AccordionGroup> |
| 65 | + |
| 66 | +## Usage |
| 67 | + |
| 68 | +### Syntax |
| 69 | + |
| 70 | +```kusto |
| 71 | +make-series [Aggregation [, ...]] |
| 72 | + [default = DefaultValue] |
| 73 | + on TimeField |
| 74 | + [in Range] |
| 75 | + step StepSize |
| 76 | + [by GroupingField [, ...]] |
| 77 | +``` |
| 78 | + |
| 79 | +### Parameters |
| 80 | + |
| 81 | +| Parameter | Description | |
| 82 | +| ---------------- | --------------------------------------------------------------------------------------------------------------- | |
| 83 | +| `Aggregation` | One or more aggregation functions (for example, `avg()`, `count()`, `sum()`) applied to each time bin, producing arrays of values. | |
| 84 | +| `default` | A value to use when no records exist in a time bin. | |
| 85 | +| `TimeField` | The field containing timestamps used for binning. | |
| 86 | +| `Range` | An optional range expression specifying the start and end of the series (for example, `from ago(1h) to now()`). | |
| 87 | +| `StepSize` | The size of each time bin (for example, `1m`, `5m`, `1h`). | |
| 88 | +| `GroupingField` | Optional fields to split the series by, producing parallel arrays for each group. | |
| 89 | + |
| 90 | +### Returns |
| 91 | + |
| 92 | +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. |
| 93 | + |
| 94 | +## Use case examples |
| 95 | + |
| 96 | +<Tabs> |
| 97 | +<Tab title="Log analysis"> |
| 98 | + |
| 99 | +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. |
| 100 | + |
| 101 | +**Query** |
| 102 | + |
| 103 | +```kusto |
| 104 | +['sample-http-logs'] |
| 105 | +| make-series count() on _time from now()-24h to now() step 5m |
| 106 | +| extend moving_avg_count=series_fir(count_, dynamic([1, 1, 1, 1, 1])) |
| 107 | +| mv-expand moving_avg_count to typeof(long), count_ to typeof(long), time to typeof(datetime) |
| 108 | +| project-rename _time=time |
| 109 | +| summarize avg(moving_avg_count), avg(count_) by bin(_time, 5m) |
| 110 | +``` |
| 111 | + |
| 112 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'sample-http-logs'%5D%20%7C%20make-series%20count()%20on%20_time%20from%20now()-24h%20to%20now()%20step%205m%20%7C%20extend%20moving_avg_count%3Dseries_fir(count_%2C%20dynamic(%5B1%2C%201%2C%201%2C%201%2C%201%5D))%20%7C%20mv-expand%20moving_avg_count%20to%20typeof(long)%2C%20count_%20to%20typeof(long)%2C%20time%20to%20typeof(datetime)%20%7C%20project-rename%20_time%3Dtime%20%7C%20summarize%20avg(moving_avg_count)%2C%20avg(count_)%20by%20bin(_time%2C%205m)%22%2C%22queryOptions%22%3A%7B%22quickRange%22%3A%221d%22%7D%7D) |
| 113 | + |
| 114 | +**Output** |
| 115 | + |
| 116 | +| _time | count_ | moving_avg_count | |
| 117 | +| ------------------- | ------ | ---------------- | |
| 118 | +| 2025-09-29T10:00:00 | 120 | 118 | |
| 119 | +| 2025-09-29T10:05:00 | 130 | 122 | |
| 120 | +| 2025-09-29T10:10:00 | 110 | 121 | |
| 121 | + |
| 122 | +The query turns request counts into arrays, applies a smoothing function, and then expands the arrays back into rows for analysis. |
| 123 | + |
| 124 | +</Tab> |
| 125 | +<Tab title="OpenTelemetry traces"> |
| 126 | + |
| 127 | +You want to analyze span durations per service, storing them as arrays for later manipulation. |
| 128 | + |
| 129 | +**Query** |
| 130 | + |
| 131 | +```kusto |
| 132 | +['otel-demo-traces'] |
| 133 | +| make-series avg(duration) on _time from ago(2h) to now() step 10m by ['service.name'] |
| 134 | +``` |
| 135 | + |
| 136 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'otel-demo-traces'%5D%20%7C%20make-series%20avg(duration)%20on%20_time%20from%20ago(2h)%20to%20now()%20step%2010m%20by%20%5B'service.name'%5D%22%7D) |
| 137 | + |
| 138 | +**Output** |
| 139 | + |
| 140 | +| service.name | avg_duration | time | |
| 141 | +| --------------- | ----------------------------- | ----------------------- | |
| 142 | +| frontend | [20ms, 18ms, 22ms, 19ms, ...] | [2025-09-29T08:00, ...] | |
| 143 | +| checkout | [35ms, 40ms, 33ms, 37ms, ...] | [2025-09-29T08:00, ...] | |
| 144 | + |
| 145 | +The query produces array-encoded time series per service, which you can further process with `series_*` functions. |
| 146 | + |
| 147 | +</Tab> |
| 148 | +<Tab title="Security logs"> |
| 149 | + |
| 150 | +You want to analyze the rate of HTTP 500 errors in your logs per minute. |
| 151 | + |
| 152 | +**Query** |
| 153 | + |
| 154 | +```kusto |
| 155 | +['sample-http-logs'] |
| 156 | +| where status == '500' |
| 157 | +| make-series count() default=0 on _time from ago(30m) to now() step 1m |
| 158 | +``` |
| 159 | + |
| 160 | +[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'sample-http-logs'%5D%20%7C%20where%20status%20%3D%3D%20'500'%20%7C%20make-series%20count()%20default%3D0%20on%20_time%20from%20ago(30m)%20to%20now()%20step%201m%22%7D) |
| 161 | + |
| 162 | +**Output** |
| 163 | + |
| 164 | +| count_ | _time | |
| 165 | +| ------------------------ | ---------------------- | |
| 166 | +| [1489, 1428, 1517, 1462, 1509, ...] | ["2025-09-30T09:08:14.921301725Z", "2025-09-30T09:09:14.921301725Z", ...] | |
| 167 | + |
| 168 | +The query generates a time series of HTTP 500 error counts as an array-based time series for further analysis with `series_*` functions. |
| 169 | + |
| 170 | +</Tab> |
| 171 | +</Tabs> |
| 172 | + |
| 173 | +## List of related operators |
| 174 | + |
| 175 | +- [extend](/apl/tabular-operators/extend-operator): Creates new calculated fields, often as preparation before `make-series`. Use `extend` when you want to preprocess data for time series analysis. |
| 176 | +- [mv-expand](/apl/tabular-operators/mv-expand): Expands arrays into multiple rows. Use `mv-expand` to work with the arrays returned by `make-series`. |
| 177 | +- [summarize](/apl/tabular-operators/summarize-operator): Aggregates rows into groups but does not generate continuous time bins. Use `summarize` when you want flexible grouping without forcing evenly spaced intervals. |
| 178 | +- [top](/apl/tabular-operators/top-operator): 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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