fixes

Signed-off-by: amanycodes <amanycodes@gmail.com>

Author: amanycodes

docs/querying/functions.md

@@ -415,9 +415,10 @@ annotation, you should find and remove the source of the invalid data.
 ## `histogram_stddev()` and `histogram_stdvar()`
 
 `histogram_stddev(v instant-vector)` returns the estimated standard deviation
-of observations for each histogram sample in `v`, based on the arithmetic mean
-of the buckets where the observations lie. Float samples are ignored and do not
-show up in the returned vector.
+of observations for each histogram sample in `v`, based on the geometric mean
+(or arithmetic mean for custom bucket histogram samples) of the buckets where
+the observations lie. Float samples are ignored and do not show up in the returned
+vector.
 
 Similarly, `histogram_stdvar(v instant-vector)` returns the estimated standard
 variance of observations for each histogram sample in `v`.

promql/functions.go

@@ -1368,7 +1368,7 @@ func funcHistogramStdDev(vals []parser.Value, _ parser.Expressions, enh *EvalNod
 			switch {
 			case bucket.Lower <= 0 && bucket.Upper >= 0:
 				val = 0
-			case sample.H.Schema == -53:
+			case sample.H.UsesCustomBuckets():
 				val = (bucket.Upper + bucket.Lower) / 2.0
 			default:
 				val = math.Sqrt(bucket.Upper * bucket.Lower)
@@ -1414,7 +1414,7 @@ func funcHistogramStdVar(vals []parser.Value, _ parser.Expressions, enh *EvalNod
 			switch {
 			case bucket.Lower <= 0 && bucket.Upper >= 0:
 				val = 0
-			case sample.H.Schema == -53:
+			case sample.H.UsesCustomBuckets():
 				val = (bucket.Upper + bucket.Lower) / 2.0
 			default:
 				val = math.Sqrt(bucket.Upper * bucket.Lower)

promql/promqltest/testdata/native_histograms.test

@@ -361,7 +361,7 @@ load 10m
    histogram_stddev_stdvar_5 {{schema:0 count:10 sum:-100 z_bucket:0 n_buckets:[0 0 0 0 10]}}x1
 
 eval instant at 10m histogram_stddev(histogram_stddev_stdvar_5)
-    {} 1.3137084989847612
+    {} 1.3137084989848
 
 eval instant at 10m histogram_stdvar(histogram_stddev_stdvar_5)
     {} 1.725830020304794

web/ui/mantine-ui/src/promql/functionDocs.tsx

@@ -1267,8 +1267,8 @@ const funcDocs: Record<string, React.ReactNode> = {
 
       <p>
         <code>histogram_stddev(v instant-vector)</code> returns the estimated standard deviation of observations in a native
-        histogram, based on the arithmetic mean of the buckets where the observations lie. Samples that are not native
-        histograms are ignored and do not show up in the returned vector.
+        histogram, based on the geometric mean (or arithmetic mean for custom bucket histogram samples) of the buckets where 
+        the observations lie. Samples that are not native histograms are ignored and do not show up in the returned vector.
       </p>
 
       <p>