From 6aa91b002030acfa7d137c7d3d3342edd9b77d48 Mon Sep 17 00:00:00 2001
From: David Klank <155117116+davidjsonn@users.noreply.github.com>
Date: Wed, 28 Jan 2026 14:39:08 +0200
Subject: [PATCH] perf(trie-db): preallocate vectors in changeset computation
 (#21465)

---
 crates/trie/db/src/changesets.rs | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/crates/trie/db/src/changesets.rs b/crates/trie/db/src/changesets.rs
index deccb1df45..8b29273a0b 100644
--- a/crates/trie/db/src/changesets.rs
+++ b/crates/trie/db/src/changesets.rs
@@ -219,11 +219,12 @@ where
     let cursor_factory = InMemoryTrieCursorFactory::new(db_cursor_factory, &reverts);
 
     // Step 5: Collect all account trie nodes that changed in the target block
-    let mut account_nodes = Vec::new();
+    let account_nodes_ref = changesets.account_nodes_ref();
+    let mut account_nodes = Vec::with_capacity(account_nodes_ref.len());
     let mut account_cursor = cursor_factory.account_trie_cursor()?;
 
     // Iterate over the account nodes from the changesets
-    for (nibbles, _old_node) in changesets.account_nodes_ref() {
+    for (nibbles, _old_node) in account_nodes_ref {
         // Look up the current value of this trie node using the overlay cursor
         let node_value = account_cursor.seek_exact(*nibbles)?.map(|(_, node)| node);
         account_nodes.push((*nibbles, node_value));
@@ -235,10 +236,11 @@ where
     // Iterate over the storage tries from the changesets
     for (hashed_address, storage_changeset) in changesets.storage_tries_ref() {
         let mut storage_cursor = cursor_factory.storage_trie_cursor(*hashed_address)?;
-        let mut storage_nodes = Vec::new();
+        let storage_nodes_ref = storage_changeset.storage_nodes_ref();
+        let mut storage_nodes = Vec::with_capacity(storage_nodes_ref.len());
 
         // Iterate over the storage nodes for this account
-        for (nibbles, _old_node) in storage_changeset.storage_nodes_ref() {
+        for (nibbles, _old_node) in storage_nodes_ref {
             // Look up the current value of this storage trie node
             let node_value = storage_cursor.seek_exact(*nibbles)?.map(|(_, node)| node);
             storage_nodes.push((*nibbles, node_value));