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 94336c6a644bf913d366baa71c2372eb67b6e2cd..723adafaf82a664b8bfff9d7d11e43e3eafafa6e 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 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 f71a1401d229b32557f0444ce45cfa47ffa2fde4..b3d3e023d10fe6bb964fe7a3d1cbb96d6a406283 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -813,7 +813,7 @@ 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());