From 1231c90a19048fac1b4bd92a89e38f8c970053a6 Mon Sep 17 00:00:00 2001
From: "Johan T. Halseth" <johanth@gmail.com>
Date: Wed, 20 Jan 2021 09:52:31 +0100
Subject: [PATCH] routing: avoid open DB transaction if no zombies to prune

We add a simple length check to the channels to be pruned to avoid
opening the DB if there is nothing to be done.
---
 routing/router.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/routing/router.go b/routing/router.go
index dc133b9b..f5ee52f1 100644
--- a/routing/router.go
+++ b/routing/router.go
@@ -897,6 +897,9 @@ func (r *ChannelRouter) pruneZombieChans() error {
 	}
 
 	log.Infof("Pruning %v zombie channels", len(chansToPrune))
+	if len(chansToPrune) == 0 {
+		return nil
+	}
 
 	// With the set of zombie-like channels obtained, we'll do another pass
 	// to delete them from the channel graph.