From 963c26550a65fdc886c94ca990331a774eefd5be Mon Sep 17 00:00:00 2001
From: Dan Cline <6798349+Rjected@users.noreply.github.com>
Date: Fri, 23 Jan 2026 20:13:01 +0000
Subject: [PATCH] fix(trie): only clone required keys in on_prefetch_proofs
 (#21378)

---
 .../tree/src/tree/payload_processor/multiproof.rs   | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/crates/engine/tree/src/tree/payload_processor/multiproof.rs b/crates/engine/tree/src/tree/payload_processor/multiproof.rs
index 472ea08a6c..dce4544764 100644
--- a/crates/engine/tree/src/tree/payload_processor/multiproof.rs
+++ b/crates/engine/tree/src/tree/payload_processor/multiproof.rs
@@ -777,10 +777,21 @@ impl MultiProofTask {
         // [`MultiAddedRemovedKeys`]. Even if there are not any known removed keys for the account,
         // we still want to optimistically fetch extension children for the leaf addition case.
         // V2 multiproofs don't need this.
+        //
+        // Only clone the AddedRemovedKeys for accounts in the targets, not the entire accumulated
+        // set, to avoid O(n) cloning with many buffered blocks.
         let multi_added_removed_keys =
             if let VersionedMultiProofTargets::Legacy(legacy_targets) = &targets {
                 self.multi_added_removed_keys.touch_accounts(legacy_targets.keys().copied());
-                Some(Arc::new(self.multi_added_removed_keys.clone()))
+                Some(Arc::new(MultiAddedRemovedKeys {
+                    account: self.multi_added_removed_keys.account.clone(),
+                    storages: legacy_targets
+                        .keys()
+                        .filter_map(|k| {
+                            self.multi_added_removed_keys.storages.get(k).map(|v| (*k, v.clone()))
+                        })
+                        .collect(),
+                }))
             } else {
                 None
             };