From e7d93e6cc7cf1b92dd5a9e1966ce47d4078121eb Mon Sep 17 00:00:00 2001
From: Paul Hauner <paul@paulhauner.com>
Date: Tue, 21 Feb 2023 12:11:14 +1100
Subject: [PATCH] Reduce big-O complexity of address change pruning

I'm not sure this is *actually* useful, but it might come in handy if we see a
ton of address changes at the fork boundary. I know the devops team have been
testing with ~100k changes, so maybe this will help in that case.
---
 .../src/bls_to_execution_changes.rs           | 20 ++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/beacon_node/operation_pool/src/bls_to_execution_changes.rs b/beacon_node/operation_pool/src/bls_to_execution_changes.rs
index c73666e145..9978bd5a98 100644
--- a/beacon_node/operation_pool/src/bls_to_execution_changes.rs
+++ b/beacon_node/operation_pool/src/bls_to_execution_changes.rs
@@ -106,6 +106,16 @@ impl<T: EthSpec> BlsToExecutionChanges<T> {
         spec: &ChainSpec,
     ) {
         let mut validator_indices_pruned = vec![];
+        let recently_changed_indices: HashSet<u64> = head_block
+            .message()
+            .body()
+            .bls_to_execution_changes()
+            .map_or(HashSet::default(), |recent_changes| {
+                recent_changes
+                    .iter()
+                    .map(|c| c.message.validator_index)
+                    .collect()
+            });
 
         self.queue.retain(|address_change| {
             let validator_index = address_change.as_inner().message.validator_index;
@@ -114,15 +124,7 @@ impl<T: EthSpec> BlsToExecutionChanges<T> {
                 .get(validator_index as usize)
                 .map_or(true, |validator| {
                     let prune = validator.has_eth1_withdrawal_credential(spec)
-                        && head_block
-                            .message()
-                            .body()
-                            .bls_to_execution_changes()
-                            .map_or(true, |recent_changes| {
-                                !recent_changes
-                                    .iter()
-                                    .any(|c| c.message.validator_index == validator_index)
-                            });
+                        && !recently_changed_indices.contains(&validator_index);
                     if prune {
                         validator_indices_pruned.push(validator_index);
                     }