From b22889534595582fce87e730c5c0e1a27fe6f526 Mon Sep 17 00:00:00 2001 From: Joshua MacDonald Date: Wed, 15 Apr 2020 20:48:59 -0700 Subject: [PATCH] Remove default keys from metrics spec (#565) --- specification/metrics/api.md | 33 --------------------------------- 1 file changed, 33 deletions(-) diff --git a/specification/metrics/api.md b/specification/metrics/api.md index e1e776d93fb..a8b248b8da1 100644 --- a/specification/metrics/api.md +++ b/specification/metrics/api.md @@ -8,7 +8,6 @@ * [Meter Interface](#meter-interface) * [Aggregations](#aggregations) * [Time](#time) - * [WithRecommendedKeys declaration on metric instruments](#withrecommendedkeys-declaration-on-metric-instruments) * [Metric Event Format](#metric-event-format) - [Three kinds of instrument](#three-kinds-of-instrument) * [Counter](#counter) @@ -198,38 +197,6 @@ use of this term for the SDK specification, to refer to parts of a data format that express explicitly timestamped values, in a sequence, resulting from an aggregation of raw measurements over time. -### WithRecommendedKeys declaration on metric instruments - -A standard feature of metric SDKs is to pre-aggregate metric events -according to a specified set of label keys (i.e., dimensions). To -perform this task, the SDK must aggregate metric events over the -collection interval: (1) across time, (2) across key dimensions in -_label space_. - -When aggregating across spatial dimensions, metric events for different sets of -labels are combined into an aggregated value for each distinct "group" of -values for the key dimensions. It means that measurements are combined for all -metric events having the same values for selected keys, explicitly disregarding -any additional labels with keys not in the set of aggregation keys. Some -exporters are known to require pre-specifying the label keys used for -aggregation (e.g., Prometheus). - -For example, if `[ak1, ak2]` are the aggregation keys and `[ik1, -ik2]` are the ignored keys, then a metric event having labels -`{ak1=A, ak2=B, ik1=C, ik1=D}` will be combined with a metric -event having labels `{ak1=A, ak2=B, ik1=Y, ik1=Z}` because they -have identical label values for all of the aggregation keys. - -The API provides a `WithRecommendedKeys` option for the user to declare the -recommended aggregation keys when declaring new metric instruments, -intended as the default way to configure an exporter for -pre-aggregation, if it is expected. Since this is only expected in -some exporters, it is regarded as an option relevant to the exporter, -whether keys configured through `WithRecommendedKeys` are applied for aggregation -purposes or not. This allows the user to influence the standard -implementation behavior, especially for exporters that require -pre-specified aggregation keys. - ### Metric Event Format Metric events have the same logical representation, regardless of