From 5383f4b08e31b8ff828ca3cfad419a4a9fe10cc3 Mon Sep 17 00:00:00 2001
From: Matthias Seitz <matthias.seitz@outlook.de>
Date: Tue, 11 Feb 2025 19:09:37 +0100
Subject: [PATCH] perf: only fetch parent if not latest (#14412)

---
 crates/rpc/rpc/src/validation.rs | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/crates/rpc/rpc/src/validation.rs b/crates/rpc/rpc/src/validation.rs
index cd512b488..e1597aaac 100644
--- a/crates/rpc/rpc/src/validation.rs
+++ b/crates/rpc/rpc/src/validation.rs
@@ -139,14 +139,23 @@ where
         let latest_header =
             self.provider.latest_header()?.ok_or_else(|| ValidationApiError::MissingLatestBlock)?;
 
-        let parent_header = self
-            .provider
-            .sealed_header_by_hash(block.parent_hash())?
-            .ok_or_else(|| ValidationApiError::MissingParentBlock)?;
+        let parent_header = if block.parent_hash() == latest_header.hash() {
+            latest_header
+        } else {
+            // parent is not the latest header so we need to fetch it and ensure it's not too old
+            let parent_header = self
+                .provider
+                .sealed_header_by_hash(block.parent_hash())?
+                .ok_or_else(|| ValidationApiError::MissingParentBlock)?;
+
+            if latest_header.number().saturating_sub(parent_header.number()) >
+                self.validation_window
+            {
+                return Err(ValidationApiError::BlockTooOld)
+            }
+            parent_header
+        };
 
-        if latest_header.number().saturating_sub(parent_header.number()) > self.validation_window {
-            return Err(ValidationApiError::BlockTooOld)
-        }
         self.consensus.validate_header_against_parent(block.sealed_header(), &parent_header)?;
         self.validate_gas_limit(registered_gas_limit, &parent_header, block.sealed_header())?;
         let parent_header_hash = parent_header.hash();