From 906b1664a3c1d0afafbf48e0f399389943eac0be 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 5208dbc..f8bfc2d 100644
--- a/src/main/java/net/minecraft/server/Chunk.java
+++ b/src/main/java/net/minecraft/server/Chunk.java
@@ -942,7 +942,7 @@ 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 f331f41..d34c4e9 100644
--- a/src/main/java/net/minecraft/server/MinecraftServer.java
+++ b/src/main/java/net/minecraft/server/MinecraftServer.java
@@ -657,7 +657,17 @@ public abstract class MinecraftServer implements Runnable, ICommandListener, 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 5d12a5c..a4d396d 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftWorld.java
@@ -742,12 +742,17 @@ 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) {
-- 
2.1.4