From da6cb3894e8defb87daa54edc997d903bbacba75 Mon Sep 17 00:00:00 2001 From: David Ashpole Date: Wed, 25 Feb 2026 20:43:58 +0000 Subject: [PATCH] reformat cumulative start time spec for clarity --- specification/metrics/sdk.md | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/specification/metrics/sdk.md b/specification/metrics/sdk.md index 6cf2db58a99..d92b14d4208 100644 --- a/specification/metrics/sdk.md +++ b/specification/metrics/sdk.md @@ -792,14 +792,15 @@ first collection interval for the instrument. This implies that all data points with delta temporality aggregation for an instrument MUST share the same start timestamp. -Cumulative aggregations for synchronous instruments SHOULD use the time of the -first measurement for each attribute set as the start time. Cumulative -aggregations for asynchronous instruments SHOULD use the most recent collection -interval's timestamp. If this is the first collection interval for the -aggregation, it SHOULD use the creation time of the instrument. To do this, the -SDK SHOULD track the start timestamp for each unique attribute set of cumulative -aggregations. All cumulative timeseries MUST use the initial start timestamp in -subsequent collection intervals. +Cumulative timeseries MUST use a consistent start timestamp for all collection +intervals. +For synchronous instruments, the start timestamp SHOULD be the time of the +first measurement for the series. +For asynchronous instrument, the start timestamp SHOULD be: +  - The creation time of the instrument, if the first series measurement + occurred in the first collection interval, +  - Otherwise, the timestamp of the collection interval prior to the first + series measurement. ### Cardinality limits