This page explains how to use the limit operator in APL.
The limit operator in Axiom Processing Language (APL) allows you to restrict the number of rows returned from a query. It is particularly useful when you want to see only a subset of results from large datasets, such as when debugging or previewing query outputs. The limit operator can help optimize performance and focus analysis by reducing the amount of data processed.
Use the limit operator when you want to return only the top rows from a dataset, especially in cases where the full result set is not necessary.
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.
Usage
Syntax
Parameters
N: The maximum number of rows to return. This must be a non-negative integer.
Returns
The limit operator returns the top N rows from the input dataset. If fewer than N rows are available, all rows are returned.
Use case examples
In log analysis, you often want to view only the most recent entries, and limit can help narrow the focus on those rows.
Query
Output
| _time | req_duration_ms | id | status | uri | method | geo.city | geo.country |
|---|---|---|---|---|---|---|---|
| 2024-10-17T12:00:00 | 200 | 123 | 200 | /index.html | GET | New York | USA |
| 2024-10-17T11:59:59 | 300 | 124 | 404 | /notfound.html | GET | London | UK |
This query limits the output to the first 5 rows from the ['sample-http-logs'] dataset, returning recent HTTP log entries.
In log analysis, you often want to view only the most recent entries, and limit can help narrow the focus on those rows.
Query
Output
| _time | req_duration_ms | id | status | uri | method | geo.city | geo.country |
|---|---|---|---|---|---|---|---|
| 2024-10-17T12:00:00 | 200 | 123 | 200 | /index.html | GET | New York | USA |
| 2024-10-17T11:59:59 | 300 | 124 | 404 | /notfound.html | GET | London | UK |
This query limits the output to the first 5 rows from the ['sample-http-logs'] dataset, returning recent HTTP log entries.
When analyzing OpenTelemetry traces, you may want to focus on the most recent traces.
Query
Output
| _time | duration | span_id | trace_id | service.name | kind | status_code |
|---|---|---|---|---|---|---|
| 2024-10-17T12:00:00 | 500ms | 1abc | 123xyz | frontend | server | OK |
| 2024-10-17T11:59:59 | 200ms | 2def | 124xyz | cartservice | client | OK |
This query retrieves the first 5 rows from the ['otel-demo-traces'] dataset, helping you analyze the latest traces.
For security log analysis, you might want to review the most recent login attempts to ensure no anomalies exist.
Query
Output
| _time | req_duration_ms | id | status | uri | method | geo.city | geo.country |
|---|---|---|---|---|---|---|---|
| 2024-10-17T12:00:00 | 300 | 567 | 401 | /login.html | POST | Berlin | Germany |
| 2024-10-17T11:59:59 | 250 | 568 | 401 | /login.html | POST | Sydney | Australia |
This query limits the output to 5 unauthorized access attempts (401 status code) from the ['sample-http-logs'] dataset.