From 08c5549055aca8426ee3820b62345d74a4f24f77 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Peter=20=C5=A0tibran=C3=BD?= <pstibrany@gmail.com>
Date: Thu, 30 Jan 2020 15:00:32 +0100
Subject: [PATCH] Document that NewMergeSeriesSet expects individual sets to be
 sorted. (#6718)
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Signed-off-by: Peter Štibraný <peter.stibrany@grafana.com>
---
 storage/fanout.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/storage/fanout.go b/storage/fanout.go
index b4746a74c..d8f87cf5c 100644
--- a/storage/fanout.go
+++ b/storage/fanout.go
@@ -388,6 +388,8 @@ type mergeSeriesSet struct {
 
 // NewMergeSeriesSet returns a new series set that merges (deduplicates)
 // series returned by the input series sets when iterating.
+// Each input series set must return its series in labels order, otherwise
+// merged series set will be incorrect.
 func NewMergeSeriesSet(sets []SeriesSet, querier *mergeQuerier) SeriesSet {
 	if len(sets) == 1 {
 		return sets[0]