From a7f2803f8e0eab7908b219b8b15996fd088f5281 Mon Sep 17 00:00:00 2001
From: maskpp <maskpp266@gmail.com>
Date: Sun, 7 Sep 2025 15:32:27 +0800
Subject: [PATCH] a small improvement to reduce gc about the latest field

---
 trie/encoding.go  | 1 -
 trie/stacktrie.go | 9 +++------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/trie/encoding.go b/trie/encoding.go
index 4cd29f531a..7d50ee4f57 100644
--- a/trie/encoding.go
+++ b/trie/encoding.go
@@ -108,7 +108,6 @@ func keybytesToHex(str []byte) []byte {
 // OBS! This method omits the termination flag.
 // OBS! The dst slice must be at least 2x as large as the key
 func writeHexKey(dst []byte, key []byte) []byte {
-	_ = dst[2*len(key)-1]
 	for i, b := range key {
 		dst[i*2] = b / 16
 		dst[i*2+1] = b % 16
diff --git a/trie/stacktrie.go b/trie/stacktrie.go
index 2b7366c3c5..19194263ba 100644
--- a/trie/stacktrie.go
+++ b/trie/stacktrie.go
@@ -59,6 +59,7 @@ func NewStackTrie(onTrieNode OnTrieNode) *StackTrie {
 		root:       stPool.Get().(*stNode),
 		h:          newHasher(false),
 		onTrieNode: onTrieNode,
+		last:       make([]byte, 64),
 		kBuf:       make([]byte, 64),
 		pBuf:       make([]byte, 64),
 	}
@@ -83,11 +84,7 @@ func (t *StackTrie) Update(key, value []byte) error {
 	if bytes.Compare(t.last, k) >= 0 {
 		return errors.New("non-ascending key order")
 	}
-	if t.last == nil {
-		t.last = append([]byte{}, k...) // allocate key slice
-	} else {
-		t.last = append(t.last[:0], k...) // reuse key slice
-	}
+	t.last = append(t.last[:0], k...) // reuse key slice
 	t.insert(t.root, k, value, t.pBuf[:0])
 	return nil
 }
@@ -95,7 +92,7 @@ func (t *StackTrie) Update(key, value []byte) error {
 // Reset resets the stack trie object to empty state.
 func (t *StackTrie) Reset() {
 	t.root = stPool.Get().(*stNode)
-	t.last = nil
+	t.last = t.last[:0]
 }
 
 // TrieKey returns the internal key representation for the given user key.