From e6db01dcbe9e14bf8de87caf0ef951166c0622bd Mon Sep 17 00:00:00 2001
From: Andrej Ocenas <mr.ocenas@gmail.com>
Date: Mon, 15 May 2023 14:24:54 +0200
Subject: [PATCH] FlameGraph: Debounce search update preventing too frequent
 rerenders  (#68405)

---
 .../components/FlameGraphHeader.tsx           | 39 +++++++++++++++++--
 1 file changed, 36 insertions(+), 3 deletions(-)

diff --git a/public/app/plugins/panel/flamegraph/components/FlameGraphHeader.tsx b/public/app/plugins/panel/flamegraph/components/FlameGraphHeader.tsx
index 8b062c10bef..46d7803a794 100644
--- a/public/app/plugins/panel/flamegraph/components/FlameGraphHeader.tsx
+++ b/public/app/plugins/panel/flamegraph/components/FlameGraphHeader.tsx
@@ -1,5 +1,7 @@
 import { css } from '@emotion/css';
-import React from 'react';
+import React, { useEffect, useState } from 'react';
+import useDebounce from 'react-use/lib/useDebounce';
+import usePrevious from 'react-use/lib/usePrevious';
 
 import { GrafanaTheme2, CoreApp } from '@grafana/data';
 import { Button, Input, RadioButtonGroup, useStyles2 } from '@grafana/ui';
@@ -53,17 +55,21 @@ const FlameGraphHeader = ({
     setSelectedBarIndex(0);
     setRangeMin(0);
     setRangeMax(1);
+    // We could set only one and wait them to sync but there is no need to debounce this.
     setSearch('');
+    setLocalSearch('');
   };
 
+  const [localSearch, setLocalSearch] = useSearchInput(search, setSearch);
+
   return (
     <div className={styles.header}>
       <div className={styles.leftContainer}>
         <div className={styles.inputContainer}>
           <Input
-            value={search || ''}
+            value={localSearch || ''}
             onChange={(v) => {
-              setSearch(v.currentTarget.value);
+              setLocalSearch(v.currentTarget.value);
             }}
             placeholder={'Search..'}
             width={44}
@@ -87,6 +93,33 @@ const FlameGraphHeader = ({
   );
 };
 
+function useSearchInput(
+  search: string,
+  setSearch: (search: string) => void
+): [string | undefined, (search: string) => void] {
+  const [localSearchState, setLocalSearchState] = useState(search);
+  const prevSearch = usePrevious(search);
+
+  // Debouncing cause changing parent search triggers rerender on both the flamegraph and table
+  useDebounce(
+    () => {
+      setSearch(localSearchState);
+    },
+    250,
+    [localSearchState]
+  );
+
+  // Make sure we still handle updates from parent (from clicking on a table item for example). We check if the parent
+  // search value changed to something that isn't our local value.
+  useEffect(() => {
+    if (prevSearch !== search && search !== localSearchState) {
+      setLocalSearchState(search);
+    }
+  }, [search, prevSearch, localSearchState]);
+
+  return [localSearchState, setLocalSearchState];
+}
+
 const getStyles = (theme: GrafanaTheme2, app: CoreApp) => ({
   header: css`
     display: flow-root;