From e88858edb19b3187283ecabae13b9c45951d5736 Mon Sep 17 00:00:00 2001
From: Leon Sorokin <leeoniya@gmail.com>
Date: Wed, 6 Mar 2024 11:27:46 -0600
Subject: [PATCH] Histogram: Fix heuristic for x axis distribution from bucket
 progression (#83975)

---
 .../src/transformations/transformers/histogram.ts        | 2 +-
 public/app/plugins/panel/histogram/Histogram.tsx         | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/packages/grafana-data/src/transformations/transformers/histogram.ts b/packages/grafana-data/src/transformations/transformers/histogram.ts
index 1f333048e8e..ea5ea3c9770 100644
--- a/packages/grafana-data/src/transformations/transformers/histogram.ts
+++ b/packages/grafana-data/src/transformations/transformers/histogram.ts
@@ -403,7 +403,7 @@ export function buildHistogram(frames: DataFrame[], options?: HistogramTransform
     }
   }
 
-  const getBucket = (v: number) => incrRoundDn(v - bucketOffset, bucketSize!) + bucketOffset;
+  const getBucket = (v: number) => roundDecimals(incrRoundDn(v - bucketOffset, bucketSize!) + bucketOffset, 9);
 
   // guess number of decimals
   let bucketDecimals = (('' + bucketSize).match(/\.\d+$/) ?? ['.'])[0].length - 1;
diff --git a/public/app/plugins/panel/histogram/Histogram.tsx b/public/app/plugins/panel/histogram/Histogram.tsx
index 04cdab00cf6..a2bb2ae2783 100644
--- a/public/app/plugins/panel/histogram/Histogram.tsx
+++ b/public/app/plugins/panel/histogram/Histogram.tsx
@@ -8,6 +8,7 @@ import {
   getFieldColorModeForField,
   getFieldSeriesColor,
   GrafanaTheme2,
+  roundDecimals,
 } from '@grafana/data';
 import {
   histogramBucketSizes,
@@ -49,12 +50,16 @@ export interface HistogramProps extends Themeable2 {
 
 export function getBucketSize(frame: DataFrame) {
   // assumes BucketMin is fields[0] and BucktMax is fields[1]
-  return frame.fields[0].type === FieldType.string ? 1 : frame.fields[1].values[0] - frame.fields[0].values[0];
+  return frame.fields[0].type === FieldType.string
+    ? 1
+    : roundDecimals(frame.fields[1].values[0] - frame.fields[0].values[0], 9);
 }
 
 export function getBucketSize1(frame: DataFrame) {
   // assumes BucketMin is fields[0] and BucktMax is fields[1]
-  return frame.fields[0].type === FieldType.string ? 1 : frame.fields[1].values[1] - frame.fields[0].values[1];
+  return frame.fields[0].type === FieldType.string
+    ? 1
+    : roundDecimals(frame.fields[1].values[1] - frame.fields[0].values[1], 9);
 }
 
 const prepConfig = (frame: DataFrame, theme: GrafanaTheme2) => {