@@ -39,7 +39,7 @@ use super::otel_utils::{
 
 pub const SERIES_HASH_COLUMN: &str = "__series_hash_u64";
 
-pub const OTEL_METRICS_KNOWN_FIELD_LIST: [&str; 38] = [
+pub const OTEL_METRICS_KNOWN_FIELD_LIST: [&str; 39] = [
     "metric_name",
     "metric_description",
     "metric_unit",
@@ -59,8 +59,12 @@ pub const OTEL_METRICS_KNOWN_FIELD_LIST: [&str; 38] = [
     "data_point_sum",
     "data_point_bucket_counts",
     "data_point_explicit_bounds",
+    "data_point_quantile_values",
     "data_point_quantile_values_quantile",
     "data_point_quantile_values_value",
+    // Histogram per-sample min/max statistics.
+    "data_point_min",
+    "data_point_max",
     "data_point_scale",
     "data_point_zero_count",
     "data_point_flags",
@@ -69,8 +73,6 @@ pub const OTEL_METRICS_KNOWN_FIELD_LIST: [&str; 38] = [
     "positive_bucket_count",
     "negative_offset",
     "negative_bucket_count",
-    "quantile",
-    "value",
     "is_monotonic",
     "aggregation_temporality",
     "aggregation_temporality_description",
@@ -358,8 +360,8 @@ fn flatten_histogram(histogram: &Histogram, flatten_exemplars: bool) -> Vec<Map<
         );
 
         insert_data_point_flags(&mut data_point_json, data_point.flags);
-        insert_number_if_some(&mut data_point_json, "min", &data_point.min);
-        insert_number_if_some(&mut data_point_json, "max", &data_point.max);
+        insert_number_if_some(&mut data_point_json, "data_point_min", &data_point.min);
+        insert_number_if_some(&mut data_point_json, "data_point_max", &data_point.max);
         insert_aggregation_temporality(&mut data_point_json, histogram.aggregation_temporality);
         data_points_json.push(data_point_json);
     }
@@ -1021,9 +1023,112 @@ mod tests {
         assert_eq!(compute_series_hash(&a), compute_series_hash(&b));
     }
 
+    fn number(value: f64) -> Value {
+        serde_json::Number::from_f64(value)
+            .map(Value::Number)
+            .unwrap_or(Value::Null)
+    }
+
+    #[test]
+    fn series_hash_ignores_histogram_min_max() {
+        // `data_point_min`/`data_point_max` are per-sample histogram
+        // statistics, not series labels. Two samples of the same series with
+        // different min/max must hash identically, otherwise histogram
+        // series fragment on every scrape.
+        let mut a = make_dp();
+        a.insert("data_point_min".to_string(), number(1.0));
+        a.insert("data_point_max".to_string(), number(9.0));
+        let mut b = make_dp();
+        b.insert("data_point_min".to_string(), number(2.0));
+        b.insert("data_point_max".to_string(), number(8.0));
+        assert_eq!(compute_series_hash(&a), compute_series_hash(&b));
+    }
+
+    #[test]
+    fn series_hash_ignores_summary_quantile_values() {
+        // `data_point_quantile_values` is the nested per-sample quantile
+        // array. Differing quantile values must not change series identity.
+        let mut a = make_dp();
+        a.insert(
+            "data_point_quantile_values".to_string(),
+            Value::Array(vec![number(0.5), number(0.9)]),
+        );
+        let mut b = make_dp();
+        b.insert(
+            "data_point_quantile_values".to_string(),
+            Value::Array(vec![number(0.7), number(0.99)]),
+        );
+        assert_eq!(compute_series_hash(&a), compute_series_hash(&b));
+    }
+
     #[test]
     fn known_field_list_contains_exemplars() {
-        assert_eq!(OTEL_METRICS_KNOWN_FIELD_LIST.len(), 38);
         assert!(OTEL_METRICS_KNOWN_FIELDS.contains("exemplars"));
     }
+
+    #[test]
+    fn series_hash_distinguishes_attribute_named_value_or_quantile() {
+        // `value` and `quantile` are only ever emitted nested inside the
+        // quantile array, never as top-level fields. They must NOT be
+        // treated as known fields: a user attribute literally named
+        // `value` or `quantile` is a real label and must affect series
+        // identity (previously it was wrongly excluded, colliding series).
+        let mut a = make_dp();
+        a.insert("value".to_string(), Value::String("x".into()));
+        let mut b = make_dp();
+        b.insert("value".to_string(), Value::String("y".into()));
+        assert_ne!(compute_series_hash(&a), compute_series_hash(&b));
+
+        let mut c = make_dp();
+        c.insert("quantile".to_string(), Value::String("p50".into()));
+        let mut d = make_dp();
+        d.insert("quantile".to_string(), Value::String("p99".into()));
+        assert_ne!(compute_series_hash(&c), compute_series_hash(&d));
+    }
+
+    #[test]
+    fn series_hash_distinguishes_attribute_named_min_or_max() {
+        // Histogram min/max statistics are emitted under the prefixed
+        // `data_point_min`/`data_point_max` keys, not bare `min`/`max`. A
+        // user attribute literally named `min` or `max` is a real label and
+        // must affect series identity.
+        let mut a = make_dp();
+        a.insert("min".to_string(), Value::String("x".into()));
+        let mut b = make_dp();
+        b.insert("min".to_string(), Value::String("y".into()));
+        assert_ne!(compute_series_hash(&a), compute_series_hash(&b));
+
+        let mut c = make_dp();
+        c.insert("max".to_string(), Value::String("x".into()));
+        let mut d = make_dp();
+        d.insert("max".to_string(), Value::String("y".into()));
+        assert_ne!(compute_series_hash(&c), compute_series_hash(&d));
+    }
+
+    #[test]
+    fn known_field_list_matches_emitted_keys() {
+        // Guard the list against drifting from the keys the flatteners
+        // actually emit as top-level data-point fields.
+        assert_eq!(OTEL_METRICS_KNOWN_FIELD_LIST.len(), 39);
+        for field in [
+            "data_point_min",
+            "data_point_max",
+            "data_point_quantile_values",
+            "data_point_quantile_values_quantile",
+            "data_point_quantile_values_value",
+            "exemplars",
+        ] {
+            assert!(
+                OTEL_METRICS_KNOWN_FIELDS.contains(field),
+                "expected `{field}` to be a known field"
+            );
+        }
+        // Removed dead entries that were never emitted as top-level keys.
+        for field in ["quantile", "value", "min", "max"] {
+            assert!(
+                !OTEL_METRICS_KNOWN_FIELDS.contains(field),
+                "`{field}` must not be a known field"
+            );
+        }
+    }
 }