From a64a253794ac64cb40befee54db53bde17dd0d49 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 7 Nov 2018 13:19:29 +0100 Subject: New upstream version 1.11.0+dfsg Signed-off-by: Daniel Baumann --- web/api/queries/median/README.md | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 web/api/queries/median/README.md (limited to 'web/api/queries/median/README.md') diff --git a/web/api/queries/median/README.md b/web/api/queries/median/README.md new file mode 100644 index 000000000..eb2dbaa96 --- /dev/null +++ b/web/api/queries/median/README.md @@ -0,0 +1,37 @@ +# Median + +The median is the value separating the higher half from the lower half of a data sample +(a population or a probability distribution). For a data set, it may be thought of as the +"middle" value. + +`median` is not an accurate average. However, it eliminates all spikes, by sorting +all the values in a period, and selecting the value in the middle of the sorted array. + +## how to use + +Use it in alarms like this: + +``` + alarm: my_alarm + on: my_chart +lookup: median -1m unaligned of my_dimension + warn: $this > 1000 +``` + +`median` does not change the units. For example, if the chart units is `requests/sec`, the result +will be again expressed in the same units. + +It can also be used in APIs and badges as `&group=median` in the URL. + +## Examples + +Examining last 1 minute `successful` web server responses: + +- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=min&after=-60&label=min) +- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=average&after=-60&label=average) +- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=median&after=-60&label=median&value_color=orange) +- ![](https://registry.my-netdata.io/api/v1/badge.svg?chart=web_log_nginx.response_statuses&options=unaligned&dimensions=success&group=max&after=-60&label=max) + +## References + +- [https://en.wikipedia.org/wiki/Median](https://en.wikipedia.org/wiki/Median). -- cgit v1.2.3