query and query_range endpoints don't return utf8 labels in metric field when grouping by utf8 label #15470
Description
What did you do?
When querying a metric with utf8 label name, I expect to get labels in the result. When I do the same without utf8 label it works. Check the metric field in both responses below:
Without utf8 labels
Query: sum by (instance)(rate(fakedata_highcard_http_requests_total{"label with space"="space"}[1m]))
{
"status": "success",
"data": {
"resultType": "matrix",
"result": [
{
"metric": {
"instance": "prometheus-high-card:9111"
},
"values": [
[
1732653240,
"449.4510109797804"
],
[
1732653255,
"453.818152726109"
],
[
1732653270,
"451.28902578051566"
]
]
}
]
}
}
With utf8 labels:
Query: sum by("label with space")(rate(fakedata_highcard_http_requests_total{"label with space"="space"}[1m]))
{
"status": "success",
"data": {
"resultType": "matrix",
"result": [
{
"metric": {},
"values": [
[
1732651560,
"437.98496120310375"
],
[
1732652430,
"415.46154615461546"
],
[
1732652445,
"423.90847816956347"
]
]
}
]
}
}
What did you expect to see?
I expect to see the labels in metric field.
What did you see instead? Under which circumstances?
I got no labels in metric field when I requested grouping by a utf8 label.
System information
Darwin 24.1.0 arm64
Prometheus version
version 3.0.0
revision c5d009d57fcccb7247e1191a0b10d74b06295388
branch HEAD
buildUser root@aa286d0eb00a
buildDate 20241114-16:43:34
goVersion go1.23.3
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