Sliding windows are a technique for generating charts using the SLIDE BY clause in conjunction with the TIMESERIES clause. With sliding windows, data is gathered in time "windows" that overlap with each other.
Tip
Sliding windows are also available via the UI in the condition advanced signal settings.
For example, in the image below, a query gathers data with 5 minute windows. The windows "slide" by 1 minute. Each window overlaps with the previous window by 4 minutes.
5-minute windows with 1-minute "slide"
In contrast, with "tumbling" or "cascading" windows, the windows do not overlap. For example, in this TIMESERIES 3 minutes NRQL query, the windows are 3 minutes in length, with each beginning when the other ends. There is no overlap in the measurement interval.
3-minute windows with no overlap or "slide".
When to use sliding windows
Sliding windows are helpful when you need to smooth out "spiky" charts. One common use case is to use sliding windows to smooth line graphs that have a lot of variation over short periods of time in cases where the rolling aggregate (for example a rolling mean) is more important than aggregates from narrow windows of time.
In the example below, data varies greatly from one minute to another, so the 1-minute tumbling window chart shows many high peaks and low valleys.
TIMESERIES query without SLIDE BY clause
However, in this example, 5-minute wide TIMESERIES windows are smoothed with the help of 1-minute SLIDE BY intervals. The query returns similar data but creates a much smoother chart.
TIMESERIES query with SLIDE BY clause
Valid NRQL syntax for SLIDE BY
Valid NRQL syntax for the SLIDE BY clause will follow the format below.
SELECT ... TIMESERIES integer1 units SLIDE BY integer2 unitsinteger1 specifies the sliding window width and integer2 specifies the SLIDE BY interval. units is a time unit, such as second, minute, hour, or day. All standard NRQL time units are accepted.
Here’s a real-life example. It shows 5-minute TIMESERIES windows with a 1-minute SLIDE BY interval.
SELECT average(duration) from Transaction TIMESERIES 5 minutes SLIDE BY 1 minuteTranslation from PromQL-style queries
When applicable, a PromQL-style query is translated into a NRQL sliding window query.
For example, if your PromQL style query uses rate(request_count[5m]) for the past 60 minutes with a 1-minute window overlap, the NRQL translation would be the query below.
SELECT rate(sum(request_count), 1 SECONDS) FROM Metric SINCE 3600 SECONDS AGO UNTIL NOW FACET dimensions() LIMIT 100 TIMESERIES 300000 SLIDE BY 60000In the translation output, the default unit of millisecond is used for TIMESERIES and SLIDE BY clauses. For TIMESERIES, 300000 ms is 300 seconds, or 5 minutes, specifying a window size of 5 minutes. For SLIDE BY, 60000 ms is 60 seconds, specifying a slide interval of 1 minute.
Use SLIDE BY with MAX and AUTO
You can combine SLIDE BY with MAX and AUTO arguments to further tailor query results, as shown in the examples below.
SELECT average(duration) FROM Transaction TIMESERIES 5 minutes SLIDE BY MAXSELECT average(duration) FROM Transaction TIMESERIES 5 minutes SLIDE BY AUTOTip
When paired with SLIDE BY, TIMESERIES does not support AUTO or MAX. The TIMESERIES value must be an integer time unit value. In other words, SLIDE BY AUTO or SLIDE BY MAX will work, but TIMESERIES AUTO or TIMESERIES MAX followed by SLIDE BY and MAX, AUTO, or a specific integer time unit is not supported.
Tip
The SLIDE BY value as determined by AUTO or MAX can produce a step interval greater than the window size, which will show up as gaps and unexpected results. If you experience these issues with query results, consider checking for instances of SLIDE BY where the step interval exceeds the window size.