From 344d01e2be231e328935c4c215e5c54c1c9e3761 Mon Sep 17 00:00:00 2001
From: Lessa <230214854+adblesss@users.noreply.github.com>
Date: Tue, 27 Jan 2026 20:51:15 -0500
Subject: [PATCH] core/rawdb: preallocate slice in iterateTransactions (#33690)

Preallocate hashes slice with known length instead of using append in a
loop. This avoids multiple reallocations during transaction indexing.
---
 core/rawdb/chain_iterator.go | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/core/rawdb/chain_iterator.go b/core/rawdb/chain_iterator.go
index 713c3d8ae2..f846d4d16c 100644
--- a/core/rawdb/chain_iterator.go
+++ b/core/rawdb/chain_iterator.go
@@ -153,9 +153,9 @@ func iterateTransactions(db ethdb.Database, from uint64, to uint64, reverse bool
 					err:    err,
 				}
 			} else {
-				var hashes []common.Hash
-				for _, tx := range body.Transactions {
-					hashes = append(hashes, tx.Hash())
+				hashes := make([]common.Hash, len(body.Transactions))
+				for i, tx := range body.Transactions {
+					hashes[i] = tx.Hash()
 				}
 				result = &blockTxHashes{
 					hashes: hashes,