papermc/CraftBukkit-Patches/0071-Improve-AutoSave-Mechanism.patch

From 3d1a1a063bb073fe32197cd248e2c99a91e22c48 Mon Sep 17 00:00:00 2001
From: md_5 <git@md-5.net>
Date: Sun, 12 Jan 2014 21:07:18 +1100
Subject: [PATCH] Improve AutoSave Mechanism

The problem here is that MinecraftServer.save(..), will attempt to sleep whilst all pending chunks are written to disk.
however due to various and complicated bugs, it will wait for an incorrect amount of chunks, which may cause it to sleep for an overly long amount of time.

Instead we will mimic the save-all command in its behaviour, which is both safe and performant.

Also, only save modified chunks, or chunks with entities after 4 auto save passes

diff --git a/src/main/java/net/minecraft/server/Chunk.java b/src/main/java/net/minecraft/server/Chunk.java
index e664e55..1412616 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -917,7 +917,7 @@ public class Chunk {
             if (this.r && this.world.getTime() != this.lastSaved || this.q) {
                 return true;
             }
-        } else if (this.r && this.world.getTime() >= this.lastSaved + 600L) {
+        } else if (this.r && this.world.getTime() >= this.lastSaved + MinecraftServer.getServer().autosavePeriod * 4) { // Spigot - Only save if we've passed 2 auto save intervals without modification
             return true;
         }
 
diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
index 7ce37c0..4a2f084 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -623,7 +623,17 @@ public abstract class MinecraftServer implements ICommandListener, Runnable, IAs
             SpigotTimings.worldSaveTimer.startTiming(); // Spigot
             this.methodProfiler.a("save");
             this.v.savePlayers();
-            this.saveChunks(true);
+            // Spigot Start
+            // We replace this with saving each individual world as this.saveChunks(...) is broken,
+            // and causes the main thread to sleep for random amounts of time depending on chunk activity
+            // Also pass flag to only save modified chunks
+            server.playerCommandState = true;
+            for (World world : worlds) {
+                world.getWorld().save(false);
+            }
+            server.playerCommandState = false;
+            // this.saveChunks(true);
+            // Spigot End
             this.methodProfiler.b();
             SpigotTimings.worldSaveTimer.stopTiming(); // Spigot
         }
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
index eeb1ecb..b8d30f5 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -693,12 +693,17 @@ public class CraftWorld implements World {
     }
 
     public void save() {
+    // Spigot start
+        save(true);
+    }
+    public void save(boolean forceSave) {
+    // Spigot end
         this.server.checkSaveState();
         try {
             boolean oldSave = world.savingDisabled;
 
             world.savingDisabled = false;
-            world.save(true, null);
+            world.save(forceSave, null); // Spigot
 
             world.savingDisabled = oldSave;
         } catch (ExceptionWorldConflict ex) {
-- 
2.1.0