From 6c0b957e95af0e1e9ca17e18d7afc386199dd9a8 Mon Sep 17 00:00:00 2001
From: Lee *!* Clagett <vtnerd@users.noreply.github.com>
Date: Fri, 19 Dec 2025 15:48:45 -0500
Subject: [PATCH] lookahead optimization for users that disabled subaddresses
 (#220)

---
 src/scanner.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/scanner.cpp b/src/scanner.cpp
index b416071..95b6586 100644
--- a/src/scanner.cpp
+++ b/src/scanner.cpp
@@ -315,6 +315,9 @@ namespace lws
 
     void update_lookahead(const account& user, subaddress_reader& reader, const db::address_index& match, const db::block_id height)
     {
+      if (match.is_zero())
+        return; // keep subaddress disabled servers quick
+
       if (!reader.disk)
         throw std::runtime_error{"Bad DB handle in scanner"};