From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Wed, 8 Apr 2020 21:24:05 -0400
Subject: [PATCH] Increase Light Queue Size

Wiz mentioned that large WorldEdit operations cause light to run on
main thread. The queue was small, set to 5.. this bumps it to 20
but makes it configurable per-world.

The main risk of increasing this higher is during shutdown, some
queued light updates may be lost because mojang did not flush the
light engine on shutdown...

The queue size only puts a cap on max loss, doesn't solve that problem.

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 98adf2fd1c2e9fe75456266ea1d7604fe64109b1..d9c59ea6faa7155d415c89228c22da3311855c9d 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -523,5 +523,10 @@ public class PaperWorldConfig {
         hoppersIgnoreOccludingBlocks = getBoolean("hopper.ignore-occluding-blocks", hoppersIgnoreOccludingBlocks);
         log("Hopper Ignore Container Entities inside Occluding Blocks: " + (hoppersIgnoreOccludingBlocks ? "enabled" : "disabled"));
     }
+
+    public int lightQueueSize = 20;
+    private void lightQueueSize() {
+        lightQueueSize = getInt("light-queue-size", lightQueueSize);
+    }
 }
 
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 8e49a648671b4d4c0d07af35ba6558b63bbf28ee..e621d683df00a7d095cc72f74357224208b0dbca 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -811,7 +811,7 @@ public abstract class MinecraftServer extends ReentrantBlockableEventLoop<TickTa
         this.executeModerately();
         // CraftBukkit end
         if (worldserver.getWorld().getKeepSpawnInMemory()) worldloadlistener.stop(); // Paper
-        chunkproviderserver.getLightEngine().setTaskPerBatch(5);
+        chunkproviderserver.getLightEngine().setTaskPerBatch(worldserver.paperConfig.lightQueueSize); // Paper - increase light queue size
         // CraftBukkit start
         // this.updateMobSpawningFlags();
         worldserver.setSpawnSettings(this.isSpawningMonsters(), this.isSpawningAnimals());