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 73d82e20d7353120a36815dc94be8c2253b2602d..6b88162d286bdabda0449d52b87457ac70f84d69 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -518,5 +518,10 @@ 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 bec5328f1ab05faab83584f75d54a5a6c830f9b7..287014feb99c67083a959f2c09213d49ad5f743d 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -809,7 +809,7 @@ 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());